A validated ultra-performance liquid chromatography with tandem mass spectrometry method for the quantification of Brazilian green propolis main compounds

Brazilian green propolis is used in folk medicine because of its various biological properties. The hydroalcoholic extract of Brazilian green propolis is characteristic for possessing several pharmacological properties. Phytochemical investigations have attributed some of these properties to the presence of compounds, which were chosen as analytical markers. This paper reports the development and analytical validation using UPLC-MS/MS in MRM mode. Veratraldehyde was used as an internal standard in qualitative and quantitative analyses of the extracts. Relative standard deviation values obtained for intra-day and inter-day precision were lower than 4%. Of the five parameters for robustness, wavelength detection and flow rate were the critical ones. Limits of detection and quantification ranged from 0.300 to 39.500 ng.mL-1 and from 1.400 to 85.00 ng.mL-1, respectively. The recoveries were between 94.00 and 119.00%, with relative standard deviation values around 5.0%. The developed method is precise, sensitive, and reliable for analysing Brazilian green propolis.

Development and validation of an analytical method based on QuEChERS followed by UHPLC-ToF-MS for the determination of tropane alkaloids in buckwheat (Fagopyrum esculentum L.) and buckwheat products

A method was developed for the determination of tropane alkaloids (TAs), including atropine, scopolamine, anisodamine and homatropine in buckwheat and related products. This work presents an optimised methodology based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction procedure followed by ultra-high performance liquid chromatography combined with time-of-flight mass spectrometry for the determination of TAs (atropine, scopolamine, anisodamine and homatropine) in buckwheat samples. The analytical methodology was successfully validated, demonstrating good linearity, low limit of quantification, repeatability (RSDr < 15%), inter-day precision (RSDR < 19%) and recovery (74-113%). Finally, 13 commercial samples of buckwheat were analysed and the results demonstrated that they were in compliance with the current European regulations regarding TAs.

The Analytical Validity of Stride Detection and Gait Parameters Reconstruction Using the Ankle-Mounted Inertial Measurement Unit Syde®

The increasing use of inertial measurement units (IMU) in biomedical sciences brings new possibilities for clinical research. The aim of this paper is to demonstrate the accuracy of the IMU-based wearable Syde® device, which allows day-long and remote continuous gait recording in comparison to a reference motion capture system. Twelve healthy subjects (age: 23.17 ± 2.04, height: 174.17 ± 6.46 cm) participated in a controlled environment data collection and performed a series of gait tasks with both systems attached to each ankle. A total of 2820 strides were analyzed. The results show a median absolute stride length error of 1.86 cm between the IMU-based wearable device reconstruction and the motion capture ground truth, with the 75th percentile at 3.24 cm. The median absolute stride horizontal velocity error was 1.56 cm/s, with the 75th percentile at 2.63 cm/s. With a measurement error to the reference system of less than 3 cm, we conclude that there is a valid physical recovery of stride length and horizontal velocity from data collected with the IMU-based wearable Syde® device.

Challenges in the Metabolomics-Based Biomarker Validation Pipeline

As end-products of the intersection between the genome and environmental influences, metabolites represent a promising approach to the discovery of novel biomarkers for diseases. However, many potential biomarker candidates identified by metabolomics studies fail to progress beyond analytical validation for routine implementation in clinics. Awareness of the challenges present can facilitate the development and advancement of innovative strategies that allow improved and more efficient applications of metabolite-based markers in clinical settings. This minireview provides a comprehensive summary of the pre-analytical factors, required analytical validation studies, and kit development challenges that must be resolved before the successful translation of novel metabolite biomarkers originating from research. We discuss the necessity for strict protocols for sample collection, storage, and the regulatory requirements to be fulfilled for a bioanalytical method to be considered as analytically validated. We focus especially on the blood as a biological matrix and liquid chromatography coupled with tandem mass spectrometry as the analytical platform for biomarker validation. Furthermore, we examine the challenges of developing a commercially viable metabolomics kit for distribution. To bridge the gap between the research lab and clinical implementation and utility of relevant metabolites, the understanding of the translational challenges for a biomarker panel is crucial for more efficient development of metabolomics-based precision medicine.

Analytical validation of NeXT Personal®, an ultra-sensitive personalized circulating tumor DNA assay

We describe the analytical validation of NeXT Personal®, an ultra-sensitive, tumor-informed circulating tumor DNA (ctDNA) assay for detecting residual disease, monitoring therapy response, and detecting recurrence in patients diagnosed with solid tumor cancers. NeXT Personal uses whole genome sequencing of tumor and matched normal samples combined with advanced analytics to accurately identify up to ~1,800 somatic variants specific to the patient's tumor. A personalized panel is created, targeting these variants and then used to sequence cell-free DNA extracted from patient plasma samples for ultra-sensitive detection of ctDNA. The NeXT Personal analytical validation is based on panels designed from tumor and matched normal samples from two cell lines, and from 123 patients across nine cancer types. Analytical measurements demonstrated a detection threshold of 1.67 parts per million (PPM) with a limit of detection at 95% (LOD95) of 3.45 PPM. NeXT Personal showed linearity over a range of 0.8 to 300,000 PPM (Pearson correlation coefficient = 0.9998). Precision varied from a coefficient of variation of 12.8% to 3.6% over a range of 25 to 25,000 PPM. The assay targets 99.9% specificity, with this validation study measuring 100% specificity and in silico methods giving us a confidence interval of 99.92 to 100%. In summary, this study demonstrates NeXT Personal as an ultra-sensitive, highly quantitative and robust ctDNA assay that can be used to detect residual disease, monitor treatment response, and detect recurrence in patients.

Analytical validation of HER2DX genomic test for early-stage HER2-positive breast cancer

BACKGROUND

HER2DX, a multianalyte genomic test, has been clinically validated to predict breast cancer recurrence risk (relapse risk score), the probability of achieving pathological complete response post-neoadjuvant therapy (pCR likelihood score), and individual ERBB2 messenger RNA (mRNA) expression levels in patients with early-stage human epidermal growth factor receptor 2 (HER2)-positive breast cancer. This study delves into the comprehensive analysis of HER2DX's analytical performance.

MATERIALS AND METHODS

Precision and reproducibility of HER2DX risk, pCR, and ERBB2 mRNA scores were assessed within and between laboratories using formalin-fixed paraffin-embedded (FFPE) tumor tissues and purified RNA. Robustness was appraised by analyzing the impact of tumor cell content and protocol variations including different instruments, reagent lots, and different RNA extraction kits. Variability was evaluated across intratumor biopsies and genomic platforms [RNA sequencing (RNAseq) versus nCounter], and according to protocol variations.

RESULTS

Precision analysis of 10 FFPE tumor samples yielded a maximal standard error of 0.94 across HER2DX scores (1-99 scale). High reproducibility of HER2DX scores across 29 FFPE tumors and 20 RNAs between laboratories was evident (correlation coefficients >0.98). The probability of identifying score differences >5 units was ≤5.2%. No significant variability emerged based on platform instruments, reagent lots, RNA extraction kits, or TagSet thaw/freeze cycles. Moreover, HER2DX displayed robustness at low tumor cell content (10%). Intratumor variability across 212 biopsies (106 tumors) was <4.0%. Concordance between HER2DX scores from 30 RNAs on RNAseq and nCounter platforms exceeded 90.0% (Cohen's κ coefficients >0.80).

CONCLUSIONS

The HER2DX assay is highly reproducible and robust for the quantification of recurrence risk, pCR likelihood, and ERBB2 mRNA expression in early-stage HER2-positive breast cancer.

Development and validation of method for the simultaneous determination of sulfamethazine, trimethoprim and doxycycline in veterinary formulation using high performance liquid chromatography

Sulfamethazine (SMZ), trimethoprim (TMP) and doxycycline (DOXY) are drugs of choice used in the treatment of intestinal and respiratory infections that affect poultry and swine. The aim of this study was develop and validate a simple, sensitive and fast method for the simultaneous determination of SMZ, TMP and DOXY in veterinary formulations by high-performance liquid chromatography. The separation was performed on a Macherey-Nagel C8 analytical column (4 × 125 mm, 5 μm), with a flow rate of 0.5 ml min-1 and detection at 268, 270 and 350 nm, for SMZ, TMP and DOXY, respectively. All measurements were performed in acetonitrile-water (45:55 v/v; pH 3.0). The analytical curves were linear (r > 0.9997) in the concentration range of 5.0-35.0 μg ml-1 for SMZ, 1.0-7.0 μg ml-1 for TMP and 7.0-13.0 μg ml-1 for DOXY. The method proved to be precise, robust, accurate and selective. In accelerated stability, the sample was analyzed for 6 months, with no major variations observed in organoleptic analysis and pH. Therefore, the developed method was proved to be suitable for routine quality control analyses for the simultaneous determination of SMZ, TMP and DOXY in pharmaceutical formulations.

Analytical Validation of Aptamer-Based Serum Vancomycin Monitoring Relative to Automated Immunoassays

The practice of monitoring therapeutic drug concentrations in patient biofluids can significantly improve clinical outcomes while simultaneously minimizing adverse side effects. A model example of this practice is vancomycin dosing in intensive care units. If dosed correctly, vancomycin can effectively treat methicillin-resistant streptococcus aureus (MRSA) infections. However, it can also induce nephrotoxicity or fail to kill the bacteria if dosed too high or too low, respectively. Although undeniably important to achieve effectiveness, therapeutic drug monitoring remains inconvenient in practice due primarily to the lengthy process of sample collection, transport to a centralized facility, and analysis using costly instrumentation. Adding to this workflow is the possibility of backlogs at centralized clinical laboratories, which is not uncommon and may result in additional delays between biofluid sampling and concentration measurement, which can negatively affect clinical outcomes. Here, we explore the possibility of using point-of-care electrochemical aptamer-based (E-AB) sensors to minimize the time delay between biofluid sampling and drug measurement. Specifically, we conducted a clinical agreement study comparing the measurement outcomes of E-AB sensors to the benchmark automated competitive immunoassays for vancomycin monitoring in serum. Our results demonstrate that E-ABs are selective for free vancomycin─the active form of the drug, over total vancomycin. In contrast, competitive immunoassays measure total vancomycin, including both protein-bound and free drug. Accounting for these differences in a pilot study consisting of 85 clinical samples, we demonstrate that the E-AB vancomycin measurement achieved a 95% positive correlation rate with the benchmark immunoassays. Therefore, we conclude that E-AB sensors could provide clinically useful stratification of patient samples at trough sampling to guide effective vancomycin dose recommendations.

Validation of the VirCapSeq-VERT system for differential diagnosis, detection, and surveillance of viral infections

IMPORTANCE

Broad range assay for accurate and sensitive diagnostics.

Development and Validation of PCR Diagnostic Assays for Detection of Avibacterium paragallinarum and Ornithobacterium rhinotracheale

PCR is the most effective method for detecting difficult-to-cultivate pathogens and pathogens that are part of mixed infections in animals, such as Ornithobacterium rhinotracheale, which causes bird ornithobacteriosis, or Avibacterium paragallinarum, which causes infectious coryza. In this work, we developed and validated two efficient and sensitive diagnostic assays for the rapid and accurate detection of A. paragallinarum and O. rhinotracheale DNA in bacterial isolates and clinical samples using real-time PCR with TaqMan-like probes. When designing the PCR assays, we performed in silico analysis, optimized DNA isolation methods and PCR conditions, and assessed the analytical and diagnostic performance of PCR. We designed primers and probes that have no mismatches with published whole-genome sequences of bacteria. The optimization of conditions showed that the PCR assays are sufficiently robust to changes in temperature and oligonucleotide concentration. The validation showed that the developed assays have high analytical and diagnostic sensitivity and specificity. These assays are expected to improve the differential diagnosis of respiratory diseases in chickens and turkeys.

RAD51 as a biomarker for homologous recombination deficiency in high-grade serous ovarian carcinoma: robustness and interobserver variability of the RAD51 test

The RAD51 test is emerging as a promising biomarker for the assessment of functional homologous recombination deficiency (HRD). Yet, the robustness and reproducibility of the immunofluorescence-based RAD51 test, in different academic laboratories, have not been systematically investigated. Therefore, we tested the performance of the RAD51 assay in formalin-fixed paraffin-embedded (FFPE) high-grade serous ovarian carcinoma (HGSOC) samples in four European laboratories. Here, we confirm that subtle differences in staining procedures result in low variability of RAD51 and γH2AX scores. However, substantial variability in RAD51 scoring was observed in some samples, likely due to complicating technical and biological features, such as high RAD51 signal-to-noise ratio and RAD51 heterogeneity. These results support the need to identify and perform additional quality control steps and/or automating image analysis. Altogether, resolving technical issues should be a priority, as identifying tumours with functional HRD is urgently needed to guide the individual treatment of HGSOC patients. Follow-up studies are needed to define the key tissue quality requirements to assess HRD by RAD51 in FFPE tumour samples, as this test could help in guiding the individual treatment of HGSOC patients.

Analytical Validation of an Immunohistochemical 7-Biomarker Prognostic Assay (immunoprint®) for Early-Stage Cutaneous Melanoma in Archival Tissue of Patients with AJCC v8 T2-T3 Disease

Selected patients with early-stage melanoma have a "hidden high risk" of poor oncologic outcomes. They might benefit from clinical trials, and ultimately, if warranted by trial results, judicious everyday use of adjuvant therapy. A promising tool to identify these individuals is the immunoprint® assay. This immunohistochemical 7-biomarker prognostic test was clinically validated in three independent cohorts (N = 762) to classify early-stage patients as high-risk or low-risk regarding melanoma recurrence and mortality. Using College of American Pathologists (CAP) recommendations, we analytically validated this assay in primary melanoma specimens (N = 20 patients). We assessed assay precision by determining consistency of risk classification under repeated identical conditions (repeatability) or across varying conditions (reproducibility), involving separate assay runs, operators (laboratory scientists), and/or observers (e.g., dermatopathologists). Reference classification was followed by five analytical validation phases: intra-run/intra-operator, intra-observer, inter-run, inter-operator, and inter-observer. Concordance of classifications in each phase was assessed via Fleiss' kappa (primary endpoint) and percent agreement (secondary endpoint). Seven-marker signature classification demonstrated high consistency across validation categories (Fleiss' kappa 0.864-1.000; overall percent agreement 95-100%), in 9/10 cases, exceeding, and in 1/10 cases, closely approaching, CAP's recommended 0.9 level. The 7-marker assay has now been verified to provide excellent repeatability, reproducibility, and precision, besides having been clinically validated.

Volumetric Absorptive Microsampling in the Analysis of Endogenous Metabolites

Volumetric absorptive microsampling (VAMS) has arisen as a relevant tool in biological analysis, offering simplified sampling procedures and enhanced stability. Most of the attention VAMS has received in the past decade has been from pharmaceutical research, with most of the published work employing VAMS targeting drugs or other exogenous compounds, such as toxins and pollutants. However, biomarker analysis by employing blood microsampling has high promise. Herein, a comprehensive review on the applicability of VAMS devices for the analysis of endogenous metabolites/biomarkers was performed. The study presents a full overview of the analysis process, incorporating all the steps in sample treatment and validation parameters. Overall, VAMS devices have proven to be reliable tools for the analysis of endogenous analytes with biological importance, often offering improved analyte stability in comparison with blood under ambient conditions as well as a convenient and straightforward sample acquisition model.

Analytical evaluation of a GAD65 antibodies chemiluminescence immunoassay for CSF in neurological syndromes

OBJECTIVES

Antibodies against glutamic acid decarboxylase isoform 65 (GAD-Ab) have been found in different severe neurological conditions associated with altered synthesis of γ-aminobutyric acid (GABA). Serum GAD-Ab can be found in up to 90 % of patients with type 1 diabetes mellitus (T1DM), mostly at relatively low concentrations, while high concentrations of GAD-ab are thought to be more frequently associate to a neurological condition, with levels 100-folds higher than those found in T1DM. Although CSF testing is recommended when suspecting a GAD-associated neurological syndrome, no commercial immunoassay is validated for this use and no cut-off is internationally recognized to support the diagnosis.

METHODS

In this study we validated CSF testing of GAD-Ab on an automated chemiluminescence (CLIA) immunoassay that had previously shown good agreement with ELISA on serum.

RESULTS

We tested 43 CSF from patients with typical GAD-associated neurological disorders and patients with other neurological conditions, identifying a clinical cut-off of 18 kIU/L that discriminated GAD-disease with an area under the curve (AUC) of 0.921. CLIA showed good analytical performances on repeatability and recovery tests in CSF and confirmed an excellent agreement with ELISA.

CONCLUSIONS

GAD-Ab associated neurological disorders are rare but CSF testing for GAD-Ab is a common request for neurologists when suspecting an insidious autoimmune central nervous system disease. CLIA platforms are expected to be increasingly adopted in clinical laboratories due to their flexibility and reliability, therefore studies on decisional levels should be implemented for improving the interpretation and utilization of laboratory data.

Analytical and Clinical Validation of Assays for Volumetric Absorptive Microsampling (VAMS) of Drugs in Different Blood Matrices: A Literature Review

Volumetric absorptive microsampling (VAMS) is the newest and most promising sample-collection technique for quantitatively analyzing drugs, especially for routine therapeutic drug monitoring (TDM) and pharmacokinetic studies. This technique uses an absorbent white tip to absorb a fixed volume of a sample (10-50 µL) within a few seconds (2-4 s), is more flexible, practical, and more straightforward to be applied in the field, and is probably more cost-effective than conventional venous sampling (CVS). After optimization and validation of an analytical method of a drug taken by VAMS, a clinical validation study is needed to show that the results by VAMS can substitute what is gained from CVS and to justify implementation in routine practice. This narrative review aimed to assess and present studies about optimization and analytical validation of assays for drugs taken by VAMS, considering their physicochemical drug properties, extraction conditions, validation results, and studies on clinical validation of VAMS compared to CVS. The review revealed that the bio-analysis of many drugs taken with the VAMS technique was optimized and validated. However, only a few clinical validation studies have been performed so far. All drugs that underwent a clinical validation study demonstrated good agreement between the two techniques (VAMS and CVS), but only by Bland-Altman analysis. Only for tacrolimus and mycophenolic acid were three measurements of agreement evaluated. Therefore, VAMS can be considered an alternative to CVS in routine practice, especially for tacrolimus and mycophenolic acid. Still, more extensive clinical validation studies need to be performed for other drugs.

Analytical Validation of a Novel MicroRNA Panel for Risk Stratification of Cognitive Impairment

We have been developing a novel approach to identify cognitive impairment-related biomarkers by profiling brain-enriched and inflammation-associated microRNA (miRNA) in plasma specimens of cognitively unimpaired and cognitively impaired patients. Here, we present an analytical validation of the novel miRNA panel, CogniMIR^®, using two competing quantitative PCR technologies for the expression analysis of 24 target miRNAs. Total RNA from the plasma specimens was isolated using the MagMAX mirVana Kit, and RT-qPCR was performed using stem-loop-based TaqMan and LNA-based qPCR assays. Evaluation of RNA dilution series for our target 24 miRNAs, performed by two operators on two different days, demonstrated that all CogniMIR^® panel miRNAs can be reliably and consistently detected by both qPCR technologies, with sample input as low as 20 copies in a qPCR reaction. Intra-run and inter-run repeatability and reproducibility analyses using RNA specimens demonstrated that both operators generated repeatable and consistent Cts, with R² values of 0.94 to 0.99 and 0.96 to 0.97, respectively. The study results clearly indicate the suitability of miRNA profiling of plasma specimens using either of the qPCR technologies. However, the LNA-based qPCR technology appears to be more operationally friendly and better suited for a CAP/CLIA-certified clinical laboratory.

Analytical validation of the 7-gene biosignature for prediction of recurrence risk and radiation therapy benefit for breast ductal carcinoma in situ

Purpose

Ductal carcinoma in situ (DCIS), is a noninvasive breast cancer, representing 20-25% of breast cancer diagnoses in the USA. Current treatment options for DCIS include mastectomy or breast-conserving surgery (BCS) with or without radiation therapy (RT), but optimal risk-adjusted treatment selection remains a challenge. Findings from past and recent clinical trials have failed to identify a 'low risk' group of patients who do not benefit significantly from RT after BCS. To address this unmet need, a DCIS biosignature, DCISionRT (PreludeDx, Laguna Hills, CA), was developed and validated in multiple cohorts. DCISionRT is a molecular assay with an algorithm reporting a recurrence risk score for patients diagnosed with DCIS intended to guide DCIS treatment. In this study, we present results from analytical validity, performance assessment, and clinical performance validation and clinical utility for the DCISionRT test comprised of multianalyte assays with algorithmic analysis.

Methods

The analytical validation of each molecular assay was performed based on the Clinical and Laboratory Standards Institute (CLSI) guidelines Quality Assurance for Design Control and Implementation of Immunohistochemistry Assays and the College of American Pathologists/American Society of Clinical Oncology (CAP/ASCO) recommendations for analytic validation of immunohistochemical assays.

Results

The analytic validation showed that the molecular assays that are part of DCISionRT test have high sensitivity, specificity, and accuracy/reproducibility (≥95%). The analytic precision of the molecular assays under controlled non-standard conditions had a total standard deviation of 6.6 (100-point scale), where the analytic variables (Lot, Machine, Run) each contributed <1% of the total variance. Additionally, the precision in the DCISionRT test result (DS) had a 95%CI ≤0.4 DS units under controlled non-standard conditions (Day, Lot, and Machine) for molecular assays over a wide range of clinicopathologic factor values. Clinical validation showed that the test identified 37% of patients in a low-risk group with a 10-year invasive IBR rate of ~3% and an absolute risk reduction (ARR) from RT of 1% (number needed to treat, NNT=100), while remaining patients with higher DS scores (elevated-risk) had an ARR for RT of 9% (NNT=11) and 96% clinical sensitivity for RT benefit.

Conclusion

The analytical performance of the PreludeDx DCISionRT molecular assays was high in representative formalin-fixed, paraffin-embedded breast tumor specimens. The DCISionRT test has been analytically validated and has been clinically validated in multiple peer-reviewed published studies.

Analytical validation of a multi-protein, serum-based assay for disease activity assessments in multiple sclerosis

PURPOSE

To characterize and analytically validate the MSDA Test, a multi-protein, serum-based biomarker assay developed using Olink^® PEA methodology.

EXPERIMENTAL DESIGN

Two lots of the MSDA Test panel were manufactured and subjected to a comprehensive analytical characterization and validation protocol to detect biomarkers present in the serum of patients with multiple sclerosis (MS). Biomarker concentrations were incorporated into a final algorithm used for calculating four Disease Pathway scores (Immunomodulation, Neuroinflammation, Myelin Biology, and Neuroaxonal Integrity) and an overall Disease Activity score.

RESULTS

Analytical characterization demonstrated that the multi-protein panel satisfied the criteria necessary for a fit-for-purpose validation considering the assay's intended clinical use. This panel met acceptability criteria for 18 biomarkers included in the final algorithm out of 21 biomarkers evaluated. VCAN was omitted based on factors outside of analytical validation; COL4A1 and GH were excluded based on imprecision and diurnal variability, respectively. Performance of the four Disease Pathway and overall Disease Activity scores met the established acceptability criteria.

CONCLUSIONS AND CLINICAL RELEVANCE

Analytical validation of this multi-protein, serum-based assay is the first step in establishing its potential utility as a quantitative, minimally invasive, and scalable biomarker panel to enhance the standard of care for patients with MS.

Technical feasibility of newborn screening for spinal muscular atrophy by next-generation DNA sequencing

Newborn screening (NBS) assays for spinal muscular atrophy (SMA) typically use a polymerase chain reaction (PCR) based assay to identify individuals with homozygous deletion in exon 7 of the SMN1 gene. Due to high DNA sequence homology between SMN1 and SMN2, it has previously been difficult to accurately bioinformatically map short reads from next-generation DNA sequencing (NGS) to SMN1, resulting in low analytical performance and preventing NGS being used for SMA screening. Advances in bioinformatics have allowed NGS to be used in diagnostic settings, but to date these assays have not reached the scale required for high volume population newborn screening and have not been performed on the dried blood spot samples that NBS programs currently use. Here we integrate an NGS assay using hybridisation-based capture with a customised bioinformatics algorithm and purpose designed high throughput reporting software into an existing NBS program to achieve a laboratory workflow for population SMA screening. We tested the NGS assay on over 2500 newborns born over 2 weeks in a NBS program in a technical feasibility study and show high sensitivity and specificity. Our results suggest NGS may be an alternate method for SMA screening by NBS programs, providing a multiplex testing platform on which potentially hundreds of inherited conditions could be simultaneously tested.

Analytical Method Development, Validation and Forced Degradation Study of Dapagliflozin by RP-HPLC

BACKGROUND

Worldwide, it is projected that 285 million individuals have diabetes, and by 2030, this number is expected to climb to 438 million. About 90% of cases of diabetes mellitus are type 2 (T2DM). Insulin sensitizers, such as metformin and thiazolidinediones; insulin secretagogues, such as sulfonylureas and glinides; dipeptidyl peptidase 4 (DPP-4) inhibitors; glucosidase inhibitors, or oral combination therapy are currently available treatments for type 2 diabetes. Some of these drugs exhibit serious limitations; thus, it is crucial to design an innovative therapy that is efficient and depends on a new channel.

AIM

In the current work, a stability-indicating reverse phase HPLC (RP-HPLC) technique was developed and subsequently validated for the detection of dapagliflozin in its API.

METHODS

The stability-indicating HPLC method for assay included the use of Kromasil 100-5-C8 (100 mm × 4.6 mm) column, UV detector 224 nm, mobile phase composition involving a mixture of acetonitrile:water (52:48), and a flow rate of 1.0 mL/min. ICH guidelines were followed for the method's validation. To assess the method's specificity and stability in showing characteristics, stress degradation studies were carried out. The working standard solution of dapagliflozin was exposed to 1 and 2 N HCl by refluxing 1 and 2 N NaOH with 30% hydrogen peroxide by volume and UV radiation in order to conduct a degradation study.

RESULTS

All system suitability parameters were determined to be within the intended ranges, and the drug's retention duration was discovered to be 1.67 minutes. It was also investigated as to how the drug degraded under various circumstances. The drug was discovered to be stable under situations of photolytic, thermal, neutral, alkaline, and oxidative deterioration. The developed stabilityindicating HPLC technique was validated in accordance with ICH Q2 recommendations, and the validation parameters, such as linearity, precision, and robustness, were achieved within the approved standards.

CONCLUSION

It may be concluded that this method is stability-indicating and specific, and it can be successfully applied to analyze tablet dosage forms containing dapagliflozin.

Highly sensitive liquid biopsy Duplex sequencing complements tissue biopsy to enhance detection of clinically relevant genetic variants

Background

Liquid biopsy (LB) is a promising complement to tissue biopsy for detection of clinically relevant genetic variants in cancer and mosaic diseases. A combined workflow to enable parallel tissue and LB analysis is required to maximize diagnostic yield for patients.

Methods

We developed and validated a cost-efficient combined next-generation sequencing (NGS) workflow for both tissue and LB samples, and applied Duplex sequencing technology for highly accurate detection of low frequency variants in plasma. Clinically relevant cutoffs for variant reporting and quantification were established.

Results

We investigated assay performance characteristics for very low amounts of clinically relevant variants. In plasma, the assay achieved 100% sensitivity and 92.3% positive predictive value (PPV) for single nucleotide variants (SNVs) and 91.7% sensitivity and 100% PPV for insertions and deletions (InDel) in clinically relevant hotspots with 0.5-5% variant allele frequencies (VAFs). We further established a cutoff for reporting variants (i.e. Limit of Blank, LOB) at 0.25% VAF and a cutoff for quantification (i.e. Limit of Quantification, LOQ) at 5% VAF in plasma for accurate clinical interpretation of analysis results. With our LB approach, we were able to identify the molecular cause of a clinically confirmed asymmetric overgrowth syndrome in a 10-year old child that would have remained undetected with tissue analysis as well as other molecular diagnostic approaches.

Conclusion

Our flexible and cost-efficient workflow allows analysis of both tissue and LB samples and provides clinically relevant cutoffs for variant reporting and precise quantification. Complementing tissue analysis by LB is likely to increase diagnostic yield for patients with molecular diseases.

Sensor Verification and Analytical Validation of Algorithms to Measure Gait and Balance and Pronation/Supination in Healthy Volunteers

Numerous studies have sought to demonstrate the utility of digital measures of motor function in Parkinson’s disease. Frameworks, such as V3, document digital measure development: technical verification, analytical and clinical validation. We present the results of a study to (1) technically verify accelerometers in an Apple iPhone 8 Plus and ActiGraph GT9X versus an oscillating table and (2) analytically validate software tasks for walking and pronation/supination on the iPhone plus passively detect walking measures with the ActiGraph in healthy volunteers versus human raters. In technical verification, 99.4% of iPhone and 91% of ActiGraph tests show good or excellent agreement versus the oscillating table as the gold standard. For the iPhone software task and algorithms, intraclass correlation coefficients (ICCs) > 0.75 are achieved versus the human raters for measures when walking distance is >10 s and pronation/supination when the arm is rotated more than two times. Passively detected walking start and end time was accurate to approx. 1 s and walking measures were accurate to one unit, e.g., one step. The results suggest that the Apple iPhone and ActiGraph GT9X accelerometers are fit for purpose and that task and passively collected measures are sufficiently analytically valid to assess usability and clinical validity in Parkinson’s patients.

Krebs von den Lungen-6 as Disease Severity Marker for COVID-19 Patients: Analytical Verification and Quality Assessment of the Tosoh AIA-360 Compared to Lumipulse G600II

Background: Krebs von den Lungen-6 (KL-6) has been proposed as a disease severity marker of COVID-19. All research articles reported the KL-6 assay detected through Fujirebio reagents by Lumipulse G600/G1200 instrument. In the present study, KL-6 assay was analysed through Tosoh AIA-360 and compared with analytical results by Lumipulse G600 in a population of COVID-19 patients. Materials and methods: Sixty-four patients (median age, IQR 67 (58–76) years), all hospitalized for COVID-19 interstitial pneumonia at Siena COVID Unit. KL-6 was measured by two methods, chemiluminescence enzyme immunoassay (CLEIA) and fluorescent enzyme immunoassay (FEIA) method by Lumipulse G600 II and AIA 360 systems, respectively. Results: KL-6 concentrations evaluated by Lumipulse G600II were significantly higher in severe than those in non-severe patients (p < 0.0001) as well as evaluating by AIA360 (p < 0.0001). Receiver operating curve (ROC) curve analysis showed that KL-6 concentrations, by Lumipuse G600II, distinguished severe from non-severe COVID-19 patients with an area under the curve (AUC) of 99.8% and the best cut-off value was 448 U/mL. AUROC between severe and non-severe COVID-19 patients using T0 KL-6 concentrations by AIA360 was 97.4% and the best cut-off value was 398 U/mL. According to T0 KL-6 concentrations in COVID-19 patients, Bland–Altman difference analysis revealed a mean bias of 78 ± 174.8; while using T1 KL-6 concentrations in COVID-19 patients, Bland–Altman difference analysis revealed a mean bias of 48 ± 126 (95% limits of agreement −199–295) between the Lumipulse G600 II and the AIA360 systems. Conclusions: In conclusion, our study demonstrated that CLEIA and FEIA methods for serum KL-6 detection are comparable and reliable. KL-6 was confirmed as an easily detectable and effective biomarker to identify severe COVID-19 patients.

Analytical evaluation of the Nittobo Medical tartrate resistant acid phosphatase isoform 5b (TRACP-5b) EIA and comparison with IDS iSYS in different clinically defined populations

OBJECTIVES

Tartrate-resistant acid phosphatase, isoform 5b (TRACP-5b) is a bone resorption marker not influenced by renal function or food intake. TRACP-5b can be measured with Nittobo Medical enzymatic-immunoassay and IDS-iSYS automated immunoassay. We evaluated the Nittobo assay and established reference ranges for a Western-European population. We compared Nittobo and IDS results in different well-defined clinical populations.

METHODS

We established the limits of detection and quantification (LOD-LOQ), linearity, imprecision and the reference ranges in 119 males, 50 women (<45 years) and 120 women (>60 years) for TRACP-5b with the Nittobo assay. We compared both assays in 30 hemodialyzed (HD), and 40 stage 3-5 patients suffering from chronic kidney disease (CKD), 40 patients suffering from rheumatoid arthritis and osteoporosis and 80 post-menopausal women. We measured TRACP-5b, β-crosslaps (β-CTX), bone alkaline phosphatase (B-ALP) and PTH in 20 hemodialyzed (HD) and 40 CKD patients.

RESULTS

LOD and LOQ were 0.02 and 0.35 U/L. CV ranged from 8.3 to 4.3% (2/5 samples presenting CV > desirable CV). Method was linear up to of 11.3 U/L. Upper and lower limits of normality were 0.8-7.6 U/L in men, 0.9-4.7 U/L in women <45 and 0.9-7.1 U/L in women >60. The regression equation between the 2 methods was Nittobo = 1.13 (95% CI: 1.09-1.16) × iSYS - 0.4 (95% CI: -0.5; -0.3). TRACP-5b and b-ALP were in their respective reference ranges for most of CKD and HD patients. That was not the case for β-CTX, which increased with decreasing eGFR.

CONCLUSIONS

Nittobo TRACP-5b presents interesting analytical features and a good concordance with IDS iSYS. These methods could thus potentially be harmonized.

Analytical and clinical validation of an RNA sequencing-based assay for quantitative, accurate evaluation of a molecular signature response classifier in rheumatoid arthritis

OBJECTIVES

This study reports analytical and clinical validation of a molecular signature response classifier (MSRC) that identifies rheumatoid arthritis (RA) patients who are non-responders to tumor necrosis factor-ɑ inhibitors (TNFi).

METHODS

The MSRC integrates patient-specific data from 19 gene expression features, anti-cyclic citrullinated protein serostatus, sex, body mass index, and patient global assessment into a single score.

RESULTS

The MSRC results stratified samples (N = 174) according to non-response prediction with a positive predictive value of 87.7% (95% CI: 78-94%), sensitivity of 60.2% (95% CI: 50-69%), and specificity of 77.3% (95% CI: 65-87%). The 25-point scale was subdivided into three thresholds: signal not detected (<10.6), high (≥10.6), and very high (≥18.5). The MSRC relies on sequencing of RNA extracted from blood; this assay displays high gene expression concordance between inter- and intra-assay sample (R² > 0.977) and minimal variation in cumulative gene assignment diversity, read mapping location, or gene-body coverage. The MSRC accuracy was 95.8% (46/48) for threshold concordance (no signal, high, very high). Intra- and inter-assay precision studies demonstrated high repeatability (92.6%, 25/27) and reproducibility (100%, 35/35).

CONCLUSION

The MSRC is a robust assay that accurately and reproducibly detects an RA patient's molecular signature of non-response to TNFi therapies.

Development and Validation of Two Diagnostic Real-Time PCR (TaqMan) Assays for the Detection of Bordetella avium from Clinical Samples and Comparison to the Currently Available Real-Time TaqMan PCR Assay

Bordetella avium (BA) is one of many pathogens that cause respiratory diseases in turkeys. However, other bacterial species can easily overgrow it during isolation attempts. This makes confirming the diagnosis of BA as the causative agent of turkey coryza more difficult. Currently, there are two PCR assays for the molecular detection of BA. One is conventional gel-based PCR and the other is TaqMan real-time PCR (qPCR) assay. However, multiple pitfalls were detected in both assays regarding their specificity, sensitivity, and efficiency, which limits their utility as diagnostic tools. In this study, we developed and validated two TaqMan qPCR assays and compared their performance to the currently available TaqMan qPCR. The two assays were able to correctly identify all BA isolates and showed negative results against a wide range of different microorganisms. The two assays were found to have high efficiency with a detection limit of approximately 1 × 10³ plasmid DNA Copies/mL with high repeatability and reproducibility. In comparison to the currently available TaqMan qPCR assay, the newly developed assays showed significantly higher PCR efficiencies due to superior primers and probes design. The new assays can serve as a reliable tool for the sensitive, specific, and efficient diagnosis of BA.

Analytical validation of a novel multi-target blood-based test to detect hepatocellular carcinoma

INTRODUCTION

Surveillance is essential to diagnose and more effectively treat hepatocellular carcinoma (HCC) in at-risk patients. However, the performance of currently recommended surveillance strategies is suboptimal, particularly for early-stage detection, and patient adherence remains low. Here, we establish the analytical performance of a novel liquid biopsy test to evaluate the presence of HCC.

METHODS

The multi-target HCC blood test (mt-HBT) integrates results from three DNA methylation markers (HOXA1, TSPYL5, and B3GALT6), the protein biomarker α-fetoprotein (AFP), and patient sex. The methylation markers are quantified from cell-free DNA extracted from plasma, and AFP is measured from serum. We conducted analytical validation studies on the mt-HBT, including analytical sensitivity, linearity, cross-contamination, interference, analytical accuracy, and precision.

RESULTS

The mt-HBT performance met all pre-specified analytical performance criteria. The test demonstrated high reproducibility, with ≥97% concordance relative to the expected results for six categories of surrogate samples across the test's dynamic range. Of 17 candidate interfering substances, none caused significant interference to biomarker quantitation, and no occurrences of sample-to-sample cross-contamination were observed.

CONCLUSION

These data demonstrate that the mt-HBT can produce consistent, reliable results for patients in the intended-use population, for whom surveillance is recommended.

Analytical Validation of Two Point-of-Care Assays for Serum Amyloid A Measurements in Cats

Serum Amyloid A (SAA) is one of the most sensitive tests to detect inflammation in cats. In this study, two point-of-care assays for SAA measurements in cats (FUJI DRI-CHEM IMMUNO AU CARTRIDGE vf-SAA (method A), and CUBE-VET analyser (Method B), were analytically evaluated. Regarding the imprecision precision only the method A showed intra-assay and inter-assay CV < 10% at all concentrations. Both assays showed linearity with r close to 1 and the recovery were in the range of 81-112% for assay A and 85-125% for assay B and the limit of detection were 3.75 and 0.5 mg/dL for method A and B, respectively. A previously validated method for SAA quantification SAATIA; LZ-SAA (method C) was used as gold-standard to evaluate the accuracy of the assays. Significant correlations (p < 0.0001) were found between assays A and C (r = 0.94) and B and C (r = 0.91). In addition, an overlap performance test was made using serum samples from cats with non-inflammatory and cats with inflammatory. Both assays showed higher median SAA concentrations in cats with inflammatory diseases than in cats without inflammatory diseases (p < 0.0001). In conclusion, this manuscript provides data about the possible application of two point-of-care assays for the measurement of SAA concentration in cats.

Liquid Biopsy Hotspot Variant Assays: Analytical Validation for Application in Residual Disease Detection and Treatment Monitoring

BACKGROUND

Analysis of circulating tumor DNA (ctDNA) in plasma is a powerful approach to guide decisions in personalized cancer treatment. Given the low concentration of ctDNA in plasma, highly sensitive methods are required to reliably identify clinically relevant variants.

METHODS

We evaluated the suitability of 5 droplet digital PCR (ddPCR) assays targeting KRAS, BRAF, and EGFR variants for ctDNA analysis in clinical use.

RESULTS

We investigated assay performance characteristics for very low amounts of variants, showing that the assays had very low limits of blank (0% to 0.11% variant allele frequency, VAF) and limits of quantification (0.41% to 0.7% VAF). Nevertheless, striking differences in detection and quantification of low mutant VAFs between the 5 tested assays were observed, highlighting the need for assay-specific analytical validation. Besides in-depth evaluation, a guide for clinical interpretation of obtained VAFs in plasma was developed, depending on the limits of blank and limits of quantification values.

CONCLUSION

It is possible to provide comprehensive clinical reports on actionable variants, allowing minimal residual disease detection and treatment monitoring in liquid biopsy.

Analytical validation of hepatitis B core-related antigen (HBcrAg) using dried blood spots (DBS)

Limited access to nucleic acid testing (NAT) to quantify HBV DNA levels, an essential tool to determine anti-HBV treatment eligibility, represents a significant barrier to scale up HBV diagnostic services in resource-limited countries. Hepatitis B core-related antigen (HBcrAg) has the potential to become an affordable alternative because of its low cost (US$ <15/assay) and strong correlation with HBV DNA levels in treatment-naïve patients. However, the current assay requires plasma or serum. To further facilitate its application to decentralized settings, we developed and evaluated a standardized procedure to quantify HBcrAg using dried blood spots as a tool to diagnose HBV-infected people with high viraemia. We evaluated the following elution method optimized to quantify HBcrAg: suspension of a punched blood-soaked disc (11 mm) of Whatman 903 Protein Saver Card in 450 µL of PBS 0.05% Tween 20, followed by an incubation for 4 h at room temperature and a centrifugation at 10,000 g for 10 minutes. 150 µL of DBS eluate was used to quantify HBcrAg using chemiluminescent enzyme immunoassay (LUMIPULSE^® G600II, Fujirebio). The limit of detection of dried blood spot HBcrAg in relation with HBV DNA levels was 19,115 IU/mL across the five major HBV genotypes (A/B/C/D/E). A strong linear correlation was confirmed between dried blood spot HBcrAg and HBV DNA levels (r = 0.94, p < 0.0001) in samples with high viral loads (range: 3.7-7.0 log IU/mL). The coefficient of variation ranged between 4.0-11.2% for repeatability and 3.9-12.2% for reproducibility. Analytical specificity was 100% (95% CI: 83.9-100%) in HBV-negative samples. Using our elution method, it may be possible to identify HBV-infected patients with high viraemia who need antiviral therapy using dried blood spot and HBcrAg. A large-scale clinical validation is warranted in resource-limited countries.

Analytical validation of an automated assay for the measurement of adenosine deaminase (ADA) and its isoenzymes in saliva and a pilot evaluation of their changes in patients with SARS-CoV-2 infection

OBJECTIVES

The aim of the present study was to validate a commercially available automated assay for the measurement of total adenosine deaminase (tADA) and its isoenzymes (ADA1 and ADA2) in saliva in a fast and accurate way, and evaluate the possible changes of these analytes in individuals with SARS-CoV-2 infection.

METHODS

The validation, in addition to the evaluation of precision and accuracy, included the analysis of the effects of the main procedures that are currently being used for SARS-CoV-2 inactivation in saliva and a pilot study to evaluate the possible changes in salivary tADA and isoenzymes in individuals infected with SARS-CoV-2.

RESULTS

The automated assay proved to be accurate and precise, with intra- and inter-assay coefficients of variation below 8.2%, linearity under dilution linear regression with R² close to 1, and recovery percentage between 80 and 120% in all cases. This assay was affected when the sample is treated with heat or SDS for virus inactivation but tolerated Triton X-100 and NP-40. Individuals with SARS-CoV-2 infection (n=71) and who recovered from infection (n=11) had higher mean values of activity of tADA and its isoenzymes than healthy individuals (n=35).

CONCLUSIONS

tADA and its isoenzymes ADA1 and ADA2 can be measured accurately and precisely in saliva samples in a rapid, economical, and reproducible way and can be analyzed after chemical inactivation with Triton X-100 and NP-40. Besides, the changes observed in tADA and isoenzymes in individuals with COVID-19 open the possibility of their potential use as non-invasive biomarkers in this disease.

Analytical Validation of HEARTBiT: A Blood-Based Multiplex Gene Expression Profiling Assay for Exclusionary Diagnosis of Acute Cellular Rejection in Heart Transplant Patients

BACKGROUND

HEARTBiT is a whole blood-based gene profiling assay using the nucleic acid counting NanoString technology for the exclusionary diagnosis of acute cellular rejection in heart transplant patients. The HEARTBiT score measures the risk of acute cellular rejection in the first year following heart transplant, distinguishing patients with stable grafts from those at risk for acute cellular rejection. Here, we provide the analytical performance characteristics of the HEARTBiT assay and the results on pilot clinical validation.

METHODS

We used purified RNA collected from PAXgene blood samples to evaluate the characteristics of a 12-gene panel HEARTBiT assay, for its linearity range, quantitative bias, precision, and reproducibility. These parameters were estimated either from serial dilutions of individual samples or from repeated runs on pooled samples.

RESULTS

We found that all 12 genes showed linear behavior within the recommended assay input range of 125 ng to 500 ng of purified RNA, with most genes showing 3% or lower quantitative bias and around 5% coefficient of variation. Total variation resulting from unique operators, reagent lots, and runs was less than 0.02 units standard deviation (SD). The performance of the analytically validated assay (AUC = 0.75) was equivalent to what we observed in the signature development dataset.

CONCLUSION

The analytical performance of the assay within the specification input range demonstrated reliable quantification of the HEARTBiT score within 0.02 SD units, measured on a 0 to 1 unit scale. This assay may therefore be of high utility in clinical validation of HEARTBiT in future biomarker observational trials.

Validation of a commercial enzyme immunoassay to assess urinary oxytocin in humans

Within the last decade, oxytocin (OT) has attracted a lot of attention in the context of various human social behaviors. Besides its importance in regulating physiological processes in females related to giving birth and lactation, OT is involved in the establishment and maintenance of social relationships, trust and emotion recognition. However, results are not always consistent across studies, which may partly be due to the incomplete validation of methods used to assess OT levels. Carefully validating a method before its use is of crucial importance to ensure that it can be used to accurately, reliably and repeatedly assess OT levels. With this study we evaluated a commercially available Enzyme Immunoassay to assess OT in human urine samples by conducting a careful analytical validation. Results indicate that, with regard to parallelism and immunoreactivity, human urinary OT can be assessed reliably. However, extraction methods need further improvement to optimize measures of accuracy and extraction efficiency, especially in the lower range of the assay system. Tests on OT stability indicate that OT is affected by degradation when stored at 4°C or room temperature. Storing urine samples over longer periods revealed that OT levels are most stable when stored as ethanol extracts at -20°C compared to being stored as samples at -20°C or -80°C. Although some of the validated parameters did not reach the intended quality criteria, this study highlights the importance of such in depth validation procedures and reporting results to make them available to researchers embarking on projects utilizing such methods.

Nanoparticulate Mycophenolic Acid Eye Drops - Analytical Validation of a High Performance Liquid Chromatography Assay and Stability Studies

BACKGROUND

Mycophenolic acid (MPA), an immunosuppressive agent, is used orally to reduce corneal graft rejection. However, its oral use is associated with gastrointestinal side effects.

OBJECTIVES

This study aims to prepare: MPA nanoparticle eye drops and a validated analytical method.

METHODS

Aqueous MPA eye drops were prepared by nanoencapsulation of MPA using nanomerics MET (N-palamitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan) at a MET and MPA ratio of 7.5: 1 g g-1 in the presence of glycerol (2.75% w/w). A validated MPA formulation drug substance assay was then conducted.

RESULTS

MET-MPA formulations were prepared as well as a validated assay. Assay validation parameters for the analysis of MPA in the formulation were satisfactory [Plate count = 16458, capacity Factor = 2.4, Tailing Factor = 1.02, linearity = 0.999 (0.016-0.5 mg mL-1), limit of detection = 0.056 mg mL-1, limit of quantification = 0.17 mg mL-1, accuracy = 98%, intraday and interday relative standard deviation = 0.45% and 4% respectively]. The candidate formulation (z-average mean = 66 ± 0.4 nm, polydispersity index = 0.12 ± 0.012, drug content = 1.14 ± 0.003 mg mL-1, zeta potential = +8.5 ± 1.4 mV, pH = 7.4 ± 0.02, osmolarity = 309 ± 1.5 mOSm L-1, viscosity = 1.04 ± 0.001 mPa.s) was then found to be stable for 14 days with respect to drug content at refrigeration, room and accelerated (40ºC) temperature. All other formulation parameters were within the ocular comfort range.

CONCLUSION

A validated assay (ICH and US FDA guidelines) for new MPA nanoparticle eye drops has been developed.

High-throughput fetal fraction amplification increases analytical performance of noninvasive prenatal screening

Purpose

The percentage of a maternal cell-free DNA (cfDNA) sample that is fetal-derived (the fetal fraction; FF) is a key driver of the sensitivity and specificity of noninvasive prenatal screening (NIPS). On certain NIPS platforms, >20% of women with high body mass index (and >5% overall) receive a test failure due to low FF (<4%).

Methods

A scalable fetal fraction amplification (FFA) technology was analytically validated on 1264 samples undergoing whole-genome sequencing (WGS)–based NIPS. All samples were tested with and without FFA.

Results

Zero samples had FF < 4% when screened with FFA, whereas 1 in 25 of these same patients had FF < 4% without FFA. The average increase in FF was 3.9-fold for samples with low FF (2.3-fold overall) and 99.8% had higher FF with FFA. For all abnormalities screened on NIPS, z-scores increased 2.2-fold on average in positive samples and remained unchanged in negative samples, powering an increase in NIPS sensitivity and specificity.

Conclusion

FFA transforms low-FF samples into high-FF samples. By combining FFA with WGS–based NIPS, a single round of NIPS can provide nearly all women with confident results about the broad range of potential fetal chromosomal abnormalities across the genome.

Validation and Implementation of a Highly Sensitive and Efficient Newborn Screening Assay for Mucopolysaccharidosis Type II

Mucopolysaccharidosis Type II (MPS II), also known as Hunter syndrome, is a lysosomal storage disorder (LSD) caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). MPS II satisfies all criteria defined by the Advisory Committee on Heritable Disorders in Newborns and Children (ACHDNC) for inclusion in the Recommended Uniform Screening Panel (RUSP) for newborn screening, apart from the fact that only minimal prospective population screening data are available. This report details the analytical validation, clinical validation, and implementation of a fluorometric assay for measurement of IDS activity in newborn dried blood spot (DBS) specimens at the Missouri State Public Health Laboratory (MSPHL). The assay is performed in a microwell plate format requiring approximately 15 min of hands-on time per plate and an incubation time of two hours. The analytical validation of this assay included linearity, analytical sensitivity, precision, and carry-over testing. Clinical validation was completed using more than 5000 deidentified presumptive normal newborn DBS specimens as well as seven specimens from patients known to be affected with MPS II. Following validation, MSPHL began prospective screening using the IDS assay on 1 November 2018. In the first 18 months of screening (to 30 June 2020), 146,954 specimens were prospectively screened using the method. Two newborns were identified with severe Hunter syndrome and the assay had a presumptive positive rate of 0.022%.

Generic Protocols for the Analytical Validation of Next-Generation Sequencing-Based ctDNA Assays: A Joint Consensus Recommendation of the BloodPAC's Analytical Variables Working Group

Liquid biopsy, particularly the analysis of circulating tumor DNA (ctDNA), has demonstrated considerable promise for numerous clinical intended uses. Successful validation and commercialization of novel ctDNA tests have the potential to improve the outcomes of patients with cancer. The goal of the Blood Profiling Atlas Consortium (BloodPAC) is to accelerate the development and validation of liquid biopsy assays that will be introduced into the clinic. To accomplish this goal, the BloodPAC conducts research in the following areas: Data Collection and Analysis within the BloodPAC Data Commons; Preanalytical Variables; Analytical Variables; Patient Context Variables; and Reimbursement. In this document, the BloodPAC's Analytical Variables Working Group (AV WG) attempts to define a set of generic analytical validation protocols tailored for ctDNA-based Next-Generation Sequencing (NGS) assays. Analytical validation of ctDNA assays poses several unique challenges that primarily arise from the fact that very few tumor-derived DNA molecules may be present in circulation relative to the amount of nontumor-derived cell-free DNA (cfDNA). These challenges include the exquisite level of sensitivity and specificity needed to detect ctDNA, the potential for false negatives in detecting these rare molecules, and the increased reliance on contrived samples to attain sufficient ctDNA for analytical validation. By addressing these unique challenges, the BloodPAC hopes to expedite sponsors' presubmission discussions with the Food and Drug Administration (FDA) with the protocols presented herein. By sharing best practices with the broader community, this work may also save the time and capacity of FDA reviewers through increased efficiency.

[Analytical validation of 13 biochemistry parameters (CEA, CA 19-9, amylase, lipase, sodium, potassium, chloride, creatinine, glucose, protein, albumin, LDH, triglycerides) in body fluids]

The measurement performance of 13 biochemistry parameters (CEA, CA 19-9, amylase, lipase, sodium, potassium, chloride, creatinine, glucose, protein, albumin, LDH, triglycerides) was tested in a panel of biological fluids other than blood and urine (peritoneal, pleural, pancreatic fluids ...). Our protocol, based on a risk analysis, allowed us to justify our choices and compare the performance obtained with those of the serum or plasma matrix already validated. Thus, the coefficients of variation obtained in body fluids are comparable. The assessment of accuracy (spiking and dilution tests) shows the absence of bias, which is consistent with the absence of matrix effect. The linearity studied by dilution tests shows that the upper limits of the measurement interval communicated by the supplier are applicable to body fluids. The absence of contamination and stability have been also confirmed. All analytes are stable for 3 days at room temperature, 7 days between 2 and 8̊C, and 6 months at -20̊C; except LDH and lipase. For most analytes, at least one interference (hemolysis, icterus, lipemia) was found. Finally, a bibliographical study, confronted with the experience of prescribers, led us to define optimal thresholds to help interpret patients' results. In conclusion, this work has allowed us to validate analytical methods for body fluids testing after relying on their comparability to the blood matrix. We have also been able to adapt our practices and finally be accredited according to the standard NF IN ISO 15189.

Analytical validation of the CellMax platform for early detection of cancer by enumeration of rare circulating tumor cells

The CellMax (CMx®) platform was developed to enrich for epithelial circulating tumor cells (CTCs) in the whole blood. This report provides assay performance data, including accuracy, linearity, limit of blank, limit of detection (LOD), specificity, and precision of enumeration of cancer cell line cells (CLCs) spiked in cell culture medium or healthy donor blood samples. Additionally, assay specificity was demonstrated in 32 young healthy donors and clinical feasibility was demonstrated in a cohort of 47 subjects consisting of healthy donors and patients who were colonoscopy verified to have colorectal cancer, adenomas, or a negative result. The CMx platform demonstrated high accuracy, linearity, and sensitivity for the enumeration of all CLC concentrations tested, including the extremely low range of 1 to 10 cells in 2 mL of blood, which is most relevant for early cancer detection. Theoretically, the assay LOD is 0.71 CTCs in 2 mL of blood. The analytical specificity was 100% demonstrated using 32 young healthy donor samples. We also demonstrated precision across multiple days and multiple operators, with good reproducibility of recovery efficiency. In a clinical feasibility study, the CMx platform identified 8 of 10 diseased subjects as positive (80% clinical sensitivity) and 4 of 5 controls as negative (80% clinical specificity). We also compared processing time and transportation effects for similar blood samples from two different sites and assessed an artificial intelligence-based counting method. Finally, unlike other platforms for which captured CTCs are retained on ferromagnetic beads or tethered to the slide surface, the CMx platform's unique airfoam-enabled release of CTCs allows captured cells to be transferred from a microfluidic chip to an Eppendorf tube, enabling a seamless transition to downstream applications such as genetic analyses and live cell manipulations.

Optimisation of a gas chromatography-mass spectrometry method for the simultaneous determination of tetrahydrocannabinol and its metabolites in rat urine

In order to evaluate the effect of irinotecan (IRI) on urinary elimination of delta-9-tetrahydrocannabinol (THC) in a rat experimental model, we developed an analytical method for the determination of the mass concentration of THC and its metabolites [11-hydroxy-delta-9-tetrahydrocannabinol (THC-OH) and 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH)] in the urine of rats treated only with THC and treated simultaneously with THC and irinotecan. For this purpose, hydrolysis and solid phase extraction conditions of the investigated analytes were optimised and a gas chromatography-mass spectrometry (GC-MS) method was developed to determine all three analytes in rat urine. The most effective hydrolysis method for THC, THC-OH, and THC-COOH conjugates was so-called tandem hydrolysis by the β-glucuronidase enzyme from Escherichia coli at 50 °C for 2 hours and followed by alkaline hydrolysis. The proposed method was then applied for determining concentrations of analytes in 24-hour rat urine. THC was not detected in either sample, THC-OH was detected in 50 % of samples, and THC-COOH in all of the samples. Enhanced urinary THC-COOH excretion was noted in rats administered combined treatment compared to single THC treatment. The method described herein was suitable for determining the mass concentration of THC metabolites in the rat urine due to its sensitivity (detection limits: 0.8-1.0 μg/L), accuracy (>96 %), and precision (RSD <6 %).

Validation and Clinical Applications of a Comprehensive Next Generation Sequencing System for Molecular Characterization of Solid Cancer Tissues

Identification of somatic molecular alterations in primary and metastatic solid tumor specimens can provide critical information regarding tumor biology and its heterogeneity, and enables the detection of molecular markers for clinical personalized treatment assignment. However, the optimal methods and target genes for clinical use are still being in development. Toward this end, we validated a targeted amplification-based NGS panel (Oncomine comprehensive assay v1) on a personal genome machine sequencer for molecular profiling of solid tumors. This panel covers 143 genes, and requires low amounts of DNA (20 ng) and RNA (10 ng). We used 27 FFPE tissue specimens, 10 cell lines, and 24 commercial reference materials to evaluate the performance characteristics of this assay. We also evaluated the performance of the assay on 26 OCT-embedded fresh frozen specimens (OEFF). The assay was found to be highly specific (>99%) and sensitive (>99%), with low false-positive and false-negative rates for single-nucleotide variants, indels, copy number alterations, and gene fusions. Our results indicate that this is a reliable method to determine molecular alterations in both fixed and fresh frozen solid tumor samples, including core needle biopsies.

Highly sensitive analytical method for herbicide clopyralid residue in cattle manure compost with ultraperformance liquid chromatography tandem mass spectrometry

A micro liquid-liquid extraction has been applied to sample preparation in the current authorized method for clopyralid in compost. The method rendered matrix effects practically negligible during determination with ultraperformance liquid chromatography-electrospray ionization tandem mass spectrometry with an improved limit of quantification of 0.7 µg/kg dry weight. Moreover, it had good accuracy and reproducibility. Therefore, the method is proposed as a highly effective routine analytical technique for investigating the actual status of clopyralid residue in compost.

The validation of a commercial enzyme-linked immunosorbent assay and the effect of freeze-thaw cycles of serum on the stability of cortisol and testosterone concentrations in Aceh cattle

Background: To obtain accurate measurements of cortisol (C) and testosterone (T) in Aceh cattle, commercial enzyme-linked immunosorbent assay (ELISA) kits need to be carefully validated. Moreover, repeated freeze-thaw cycles during the storage of the samples may affect the stability of the hormones in the serum. Here, the reliability of C and T concentration measurements in the serum of Aceh cattle, was tested using commercial C and T ELISA kits designed to measure human C and T concentrations. Further, the effect of repeated freeze-thaw cycles on the stability of C and T concentrations in the serum was evaluated. Methods: Commercial C (Cat. no. EIA-1887) and T (Cat. no. EIA-1559) ELISA kits from DRG Instruments GmbH were validated through an analytical validation test (i.e., parallelism, accuracy, and precision) and a biological validation test (for C: effect of transportation on the C secretion; for T: the concentrations of T between bulls and cows). To test the effects of freeze-thaw cycles, cattle serum was subjected to the following treatments: (i) remained frozen at -20 OC (control group); (ii) exposed to freeze-thaw cycles for two, four, six, and eight times (test groups).   Results: Parallelism, accuracy, and precision tests showed that both  C and T ELISA kits adequately measured C and T in the serum of Aceh cattle. Concentrations of C post-transportation were significantly higher than pre-transportation (p<0.01). Concentrations of T in bulls were significantly higher than in cows (p<0.01). After four to eight freeze-thaw cycles, C concentrations were significantly lower compared to the control group (all p < 0.05). In contrast, T concentrations remained stable (all p>0.05). Conclusions: Commercial C (EIA-1887) and T (EIA-1559) ELISA kits are reliable assays for measuring serum C and T, respectively, in Aceh cattle. Repeated freeze-thaw cycles significantly affected the stability of serum C, but did not for T.

The validation of a commercial enzyme-linked immunosorbent assay and the effect of freeze-thaw cycles of serum on the stability of cortisol and testosterone concentrations in Aceh cattle

Background: To obtain accurate measurements of cortisol (C) and testosterone (T) in Aceh cattle, commercial enzyme-linked immunosorbent assay (ELISA) kits need to be carefully validated. Moreover, repeated freeze-thaw cycles during the storage of the samples may affect the stability of the hormones in the serum. Here, the reliability of C and T concentration measurements in the serum of Aceh cattle, was tested using commercial C and T ELISA kits designed to measure human C and T concentrations. Further, the effect of repeated freeze-thaw cycles on the stability of C and T concentrations in the serum was evaluated. Methods: Commercial C (Cat. no. EIA-1887) and T (Cat. no. EIA-1559) ELISA kits from DRG Instruments GmbH were validated through an analytical validation test (i.e., parallelism, accuracy, and precision) and a biological validation test (for C: effect of transportation on the C secretion; for T: the concentrations of T between bulls and cows). To test the effects of freeze-thaw cycles, cattle serum was subjected to the following treatments: (i) remained frozen at -20 OC (control group); (ii) exposed to freeze-thaw cycles for two, four, six, and eight times (test groups).   Results: Parallelism, accuracy, and precision tests showed that both  C and T ELISA kits adequately measured C and T in the serum of Aceh cattle. Concentrations of C post-transportation were significantly higher than pre-transportation (p<0.01). Concentrations of T in bulls were significantly higher than in cows (p<0.01). After four to eight freeze-thaw cycles, C concentrations were significantly lower compared to the control group (all p < 0.05). In contrast, T concentrations remained stable (all p>0.05). Conclusions: Commercial C (EIA-1887) and T (EIA-1559) ELISA kits are reliable assays for measuring serum C and T, respectively, in Aceh cattle. Repeated freeze-thaw cycles significantly affected the stability of serum C, but did not for T.

The validation of a commercial enzyme-linked immunosorbent assay and the effect of freeze-thaw cycles of serum on the stability of cortisol and testosterone concentrations in Aceh cattle

Background: To obtain accurate measurements of cortisol (C) and testosterone (T) in Aceh cattle, commercial enzyme-linked immunosorbent assay (ELISA) kits need to be carefully validated. Moreover, repeated freeze-thaw cycles during the storage of the samples may affect the stability of the hormones in the serum. Here, the reliability of C and T concentration measurements in the serum of Aceh cattle, was tested using commercial C and T ELISA kits designed to measure human C and T concentrations. Further, the effect of repeated freeze-thaw cycles on the stability of C and T concentrations in the serum was evaluated. Methods: Commercial C (Cat. no. EIA-1887) and T (Cat. no. EIA-1559) ELISA kits from DRG Instruments GmbH were validated through an analytical validation test (i.e., parallelism, accuracy, and precision) and a biological validation test (for C: effect of transportation on the C secretion; for T: the concentrations of T between bulls and cows). To test the effects of freeze-thaw cycles, cattle serum was subjected to the following treatments: (i) remained frozen at -20 ^OC (control group); (ii) exposed to freeze-thaw cycles for two, four, six, and eight times (test groups).   Results: Parallelism, accuracy, and precision tests showed that both  C and T ELISA kits adequately measured C and T in the serum of Aceh cattle. Concentrations of C post-transportation were significantly higher than pre-transportation (p<0.01). Concentrations of T in bulls were significantly higher than in cows (p<0.01). After four to eight freeze-thaw cycles, C concentrations were significantly lower compared to the control group (all p < 0.05). In contrast, T concentrations remained stable (all p>0.05). Conclusions: Commercial C (EIA-1887) and T (EIA-1559) ELISA kits are reliable assays for measuring serum C and T, respectively, in Aceh cattle. Repeated freeze-thaw cycles significantly affected the stability of serum C, but did not for T.

Assessment of Commercially Available Immunoassays to Measure Glucocorticoid Metabolites in African Grey Parrot (Psittacus Erithacus) Droppings: A Ready Tool for Non-Invasive Monitoring of Stress

Simple Summary

The African Grey Parrot is a very popular bird commonly found in zoological collections. However, captivity can prevent it from meeting its natural needs and so become an ongoing stressor, leading sometimes to clinical and/or behavioral disorders. Non-invasive forms of stress assessment are of definite interest for monitoring welfare in captive bird populations. One notable stress outcome is the excretion of glucocorticoid metabolites (from the stress hormone corticosterone) in droppings. The aim of this study was to carefully assess methods of glucocorticoid metabolites extraction and measurement in droppings from African Grey Parrots. Several extraction and enzyme immunoassays procedures were tested, based on the evaluation of analytical quality parameters and biological relevance. The best procedure was found to be a combination of a 60% methanol extraction with the use of a commercial corticosterone enzyme immunoassay. To determine whether this method was suitable for assessing different stress levels, a significant correlation with another reliable stress marker in birds, the Heterophil: Lymphocyte Ratio, was evidenced. This method can thus be used to evaluate stress in African Gray Parrots in a non-invasive way and help to monitor their welfare in zoo populations for instance.

Abstract

Despite being undomesticated, African Grey Parrots (Psittacus erithacus) are commonly found in captivity, in zoos or as pets. Captivity can be an ongoing stressor. Non-invasive glucocorticoid metabolites (GCM) measurements from bird droppings are of interest for assessing stress but require careful evaluation in each newly studied species. This study describes the assessment of such methods for Psittacus erithacus to provide tools for evaluating stress and monitoring welfare. We evaluated 12 method combinations of GCM extraction and enzyme immunoassay (EIA) from a pool of African Grey Parrot droppings, through the validation of several analytical parameters. Then, Heterophil: Lymphocyte Ratios (HLR), another reliable stress marker, were determined and correlated to individual dropping GCM concentrations for 29 birds to determine whether the method is biologically relevant. We found that the best procedure to measure GCM in African Grey Parrot droppings is a combination of 60% methanol extraction measured using a Corticosterone EIA kit (Cayman Chemical Company) from fresh or dry droppings. The establishment of a significant correlation (Pearson coefficient correlation = 0.48; p = 0.0082) between HLR and GCM in the studied population confirmed the method biological relevance. This method can thus be applied to assess stress in Psittacus erithacus and support welfare monitoring in zoo populations.

Biomarkers in early-phase trials: fundamental issues

Biomarkers are frequently being included in early-phase clinical trials. This article is meant to introduce clinical investigators to the fundamentals of choosing a biomarker test for use in an early phase trial. Steps to consider are briefly outlined including defining the role of the biomarker in the early phase trial; selecting a fit-for-purpose biomarker test and laboratory; describing the test procedures; carrying out analytical validation testing appropriate for the research objectives and the risk involved in the trial; implementing the test in the trial; and planning for the future. Examples illustrate analytical validation approaches in the context of typical biomarker roles. The importance of collaboration between clinical investigators and laboratory researchers is emphasized.

Validation of a Commercially Available Enzyme ImmunoAssay for the Determination of Oxytocin in Plasma Samples from Seven Domestic Animal Species

The neurohormone oxytocin (OT) has a broad range of behavioral effects in mammals. It modulates a multitude of social behaviors, e.g., affiliative and sexual interactions. Consequently, the OT role in various animal species is increasingly explored. However, several issues have been raised regarding the peripheral OT measurement. Indeed, various methods have been described, leading to assay discrepancies and inconsistent results. This highlights the need for a recognized and reliable method to measure peripheral OT. Our aim was to validate a method combining a pre-extraction step, previously demonstrated as essential by several authors, and a commercially available enzyme immunoassay (EIA) for OT measurement, using plasma from seven domestic species (cat, dog, horse, cow, pig, sheep, and goat). The Oxytocin EIA kit (EnzoLifeSciences) was used to assay the solid-phase extracted samples following the manufacturer's instructions with slight modifications. For all species except dogs and cats, concentration factors were applied to work above the kit's sensitivity (15 pg/ml). To validate the method, the following performance characteristics were evaluated using Validation Samples (VS) at various concentrations in each species: extraction efficiency via spiking tests and intra- and inter-assay precision, allowing for the calculation of total errors. Parallelism studies to assess matrix effects could not be performed because of too low basal concentrations. Quantification ranges and associated precision profiles were established to account for the various OT plasma concentrations in each species. According to guidelines for bioanalytical validation of immunoassays, the measurements were sufficiently precise and accurate in each species to achieve a total error ≤30% in each VS sample. In each species, the inter-assay precision after 3 runs was acceptable, except in low concentration samples. The linearity under dilution of dogs and cats' samples was verified. Although matrix effects assessments are lacking, our results indicate that OT plasma levels can reliably be measured in several domestic animal species by the method described here. Studies involving samples with low OT plasma concentrations should pay attention to reproducibility issues. This work opens new perspectives to reliably study peripheral OT in a substantial number of domestic animal species in various behavioral contexts.

Analytical validation of a 12-gene molecular test for the prediction of distant recurrence in breast cancer

Aim:

To validate the analytical performance of a 12-gene molecular assay that predicts distant recurrence for early-stage ER+/HER2- invasive breast cancer as run within a central reference laboratory.

Materials & methods:

Formalin-fixed paraffin-embedded breast resections were evaluated by quantitative reverse transcription polymerase chain reaction for the expression of eight target genes, three housekeeper genes and one control gene to assess for DNA contamination.

Results:

The assay results were highly correlated with a validated reference laboratory. The assay had a broad linear range for input RNA, with similar amplicon efficiencies for target and housekeeper genes. The assay test was highly reproducible, with comparable inter- and intrabatch precision to the reference laboratory.

Conclusion:

These studies demonstrate that the 12-gene molecular assay is highly robust and accurate.

Several tests have been developed to aid in breast cancer treatment decisions by assessing the likelihood that an individual’s breast cancer will recur. One such test is a 12-gene molecular assay. This test provides a clinical score that combines molecular information from genes within the tumor with clinical information to determine whether a breast cancer is at high or low risk of recurrence. The data presented here show that this test is very reproducible and robust, making it appropriate and reliable for clinical use.

Clinical application of a cancer genomic profiling assay to guide precision medicine decisions

Aim:

Develop and apply a comprehensive and accurate next-generation sequencing based assay to help clinicians to match oncology patients to therapies.

Materials & methods:

The performance of the CANCERPLEX^® assay was assessed using DNA from well-characterized routine clinical formalin-fixed paraffin-embedded (FFPE) specimens and cell lines.

Results:

The maximum sensitivity of the assay is 99.5% and its accuracy is virtually 100% for detecting somatic alterations with an allele fraction of as low as 10%. Clinically actionable variants were identified in 93% of patients (930 of 1000) who underwent testing.

Conclusion:

The test's capacity to determine all of the critical genetic changes, tumor mutation burden, microsatellite instability status and viral associations has important ramifications on clinical decision support strategies, including identification of patients who are likely to benefit from immune checkpoint blockage therapies.