Interferences from blood collection tube components on clinical chemistry assays

Lithium heparin interference in the Abbott enzymatic creatinine assay: the significance of under-filled tubes

BACKGROUND

Spuriously high results using the Abbott Architect enzymatic creatinine assay were noted to be particularly associated with very small sample volumes. This led us to query the effect of under-filling lithium heparin tubes on the measured enzymatic creatinine result.

METHODS

Blood was provided by 5 laboratory personnel and then decanted into 5 x1.2 mL Sarstedt S-Monovette tubes, giving final blood volumes of 200, 400, 600, 800 and 1200 μL. Plasma was analysed using Abbott Architect Jaffe, enzymatic creatinine, Beckman Coulter (AU500) enzymatic creatinine and Roche (Cobas c702) enzymatic creatinine assays. Saline was also added to Sarstedt 1.2 mL and Teklab 2 mL tubes and analysed using the Abbott Jaffe and enzymatic creatinine methods.

RESULTS

Increasing degrees of under-fill were associated with greater over-estimation of creatinine using the Abbott enzymatic assay, but no difference was noted using Jaffe methodology on the same platform or enzymatic assays provided by Roche or Beckman. On average, creatinine was 40.6% (+27.7 μmol/L) higher when only 200 μL of blood was present in the tube. Small volumes of saline added to lithium heparin tubes measured significant creatinine concentrations using the Abbott enzymatic method.

CONCLUSIONS

Lithium heparin directly interferes in the Abbott Architect enzymatic creatinine assay. Under-filling lithium heparin tubes can lead to clinically significant over-estimation of creatinine results by this assay. Users of this assay should be aware of the potential for spurious results in small sample volumes collected into lithium heparin tubes and implement robust procedures for identifying and reporting results on these samples.

Second generation liquid platelet concentrates: A literature review

Liquid or injectable platelet rich fibrin (PRF) is a second-generation platelet concentrate which is completely autologous and free of external additives like bovine thrombin and calcium chloride. Additionally, it is the only one to be obtained in a liquid form among the second generation platelet concentrates. This allows for wide applications such as to maximize injections or mixing with biomaterials such as bone grafts or antibiotics. Since it was first introduced in 2015, several modifications of the original protocol have been proposed which aim at maximizing its biological and mechanical properties. This includes changes in centrifugation speed, time, and so on. The aim of this review is to summarize the various modifications of the injectable/liquid formation of PRF as well as to discuss the potential applications and future research direction.

The impacts of different anticoagulants and long-term frozen storage on multiple metal concentrations in peripheral blood: a comparative study

It is important but remains unclear whether ethylenediaminetetraacetic acid (EDTA) and sodium heparin anticoagulants have different impacts on the levels of various metals in peripheral blood after long-term frozen storage. The concentrations of 22 metals (Al, As, Ba, Ca, Cd, Cr, Co, Cu, Mn, Mg, Mo, Ni, Fe, Pb, Rb, Se, Sn, Sb, Sr, Ti, V, Zn) in whole blood, blood cells and plasma from 22 healthy participants were determined twice, 18 months apart, using inductively coupled plasma mass spectrometry (ICP-MS). The mean percentage error (MPE) and intraclass correlation coefficient (ICC) were calculated to evaluate the impact of the anticoagulants and long-term frozen storage on metal concentrations, respectively. The concentrations of Sb and Ba in whole blood, blood cells and plasma were significantly altered by EDTA and sodium heparin at two measurement timepoints (P < 0.05 and MPE > 80%). In EDTA tubes, the Ti and Ni concentrations in blood cells were changed significantly; and in heparin tubes, the concentrations of Ni and Mo in blood cells and Sb in plasma were also altered (P < 0.05 and MPE > 80%). The ICCs of 11 metals in whole blood, 15 metals in blood cells and 16 metals in plasma remained unchanged in EDTA tubes, and 16 metals in whole blood, 15 metals in blood cells and 17 metals in plasma remained unchanged in heparin tubes (ICC > 0.40). Our study suggested the use of EDTA tubes to determine Sb concentrations in peripheral blood and heparin tubes to determine Ba concentrations. Additionally, heparin tubes may be more suited for determining multiple metal concentrations in whole blood, whereas for blood cells and plasma either EDTA or heparin tubes could be used.

Pre-analytical sample handling effects on blood cytokine levels: quality control of a COVID-19 biobank

Aim: We investigated the effect of pre-analytical sample handling variations on coronavirus disease 2019-relevant circulating cytokine levels IFN-γ, IL-10, IL-12p70, IL-17A, IL-6 and TNF-α. Materials & methods: We collected blood in different collection tubes (ethylenediaminetetraacetic acid, sodium citrate, lithium heparin, serum), and subjected ethylenediaminetetraacetic acid plasma to among others increasing delays in centrifugation or -80°C storage. Six subjects were included in each experimental condition. Cytokine levels were measured in these samples using the Simoa Cytokine 6-plex kit. Results: Different tube types resulted in different blood cytokine levels. IL-17A and IL-6 levels declined with 3 h centrifugation delay. IFN-γ levels declined with 24 h postcentrifugation storage delay. IL-17A levels declined with 2-week storage delay. Conclusion: It is recommended to centrifuge tubes quickly following collection, for accurate cytokine measurement.

Isobutylene contamination of blood collected in 10-ml evacuated blood collection tubes with gray conventional rubber stoppers

Dual-column headspace gas chromatographic analysis with two flame-ionization detectors is a commonly used analytical technique for forensic blood ethanol quantitation. This technique is also applicable to the identification and quantitation of other volatile organic compounds such as methanol in biological samples. Compound identification by retention time is limited to those compounds with known retention times programmed into the instrument method. Historically, an early-eluting peak from an unidentified compound has been observed in both chromatograms from antemortem blood samples analyzed for ethanol concentration with this technique. The unidentified compound's retention time matches that of methanol on one column but not on the second column. This previously unidentified compound has been identified as isobutylene. The proposed source of the isobutylene contamination historically observed in antemortem blood samples collected in 10-ml gray-top blood collection tubes is the conventional rubber stopper. Isobutylene was detected in deionized water stored in each of the seven lots of 10-ml blood tubes tested; the expiration dates of the tubes tested spanned the years 2002-2022. Misidentification of isobutylene as methanol is possible when using a single-column gas chromatographic system. The presence of isobutylene in blood collected in a gray-top collection tube does not represent laboratory contamination, is not an interferent with blood ethanol quantitation, and does not affect the ethanol concentration in the blood. A 0.150 g/dl aqueous ethanol standard was stored in a gray-top tube to evaluate the potential impact of isobutylene on ethanol quantitation. The solution's average ethanol concentration measured after storage was 0.150 g/dl.

From bedside to bench-practical considerations to avoid pre-analytical pitfalls and assess sample quality for high-resolution metabolomics and lipidomics analyses of body fluids

The stability of lipids and other metabolites in human body fluids ranges from very stable over several days to very unstable within minutes after sample collection. Since the high-resolution analytics of metabolomics and lipidomics approaches comprise all these compounds, the handling of body fluid samples, and thus the pre-analytical phase, is of utmost importance to obtain valid profiling data. This phase consists of two parts, sample collection in the hospital (“bedside”) and sample processing in the laboratory (“bench”). For sample quality, the apparently simple steps in the hospital are much more critical than the “bench” side handling, where (bio)analytical chemists focus on highly standardized processing for high-resolution analysis under well-controlled conditions. This review discusses the most critical pre-analytical steps for sample quality from patient preparation; collection of body fluids (blood, urine, cerebrospinal fluid) to sample handling, transport, and storage in freezers; and subsequent thawing using current literature, as well as own investigations and practical experiences in the hospital. Furthermore, it provides guidance for (bio)analytical chemists to detect and prevent potential pre-analytical pitfalls at the “bedside,” and how to assess the quality of already collected body fluid samples. A knowledge base is provided allowing one to decide whether or not the sample quality is acceptable for its intended use in distinct profiling approaches and to select the most suitable samples for high-resolution metabolomics and lipidomics investigations.

Clinical Evaluation of the Torq Zero Delay Centrifuge System for Decentralized Blood Collection and Stabilization

Blood sample collection and rapid separation—critical preanalytical steps in clinical chemistry—can be challenging in decentralized collection settings. To address this gap, the Torq™ zero delay centrifuge system includes a lightweight, hand-portable centrifuge (ZDrive™) and a disc-shaped blood collection device (ZDisc™) enabling immediate sample centrifugation at the point of collection. Here, we report results from clinical validation studies comparing performance of the Torq System with a conventional plasma separation tube (PST). Blood specimens from 134 subjects were collected and processed across three independent sites to compare ZDisc and PST performance in the assessment of 14 analytes (K, Na, Cl, Ca, BUN, creatinine, AST, ALT, ALP, total bilirubin, albumin, total protein, cholesterol, and triglycerides). A 31-subject precision study was performed to evaluate reproducibility of plasma test results from ZDiscs, and plasma quality was assessed by measuring hemolysis and blood cells from 10 subject specimens. The ZDisc successfully collected and processed samples from 134 subjects. ZDisc results agreed with reference PSTs for all 14 analytes with mean % biases well below clinically significant levels. Results were reproducible across different operators and ZDisc production lots, and plasma blood cell counts and hemolysis levels fell well below clinical acceptance thresholds. ZDiscs produce plasma samples equivalent to reference PSTs. Results support the suitability of the Torq System for remotely collecting and processing blood samples in decentralized settings.

Comparative metabolomics studies of blood collected in streck and heparin tubes from lung cancer patients

Metabolomics analysis of blood from patients (n = 42) undergoing surgery for suspected lung cancer was performed in this study. Venous and arterial blood was collected in both Streck and Heparin tubes. A total of 96 metabolites were detected, affected by sex (n = 56), collection tube (n = 33), and blood location (n = 8). These metabolites belonged to a wide array of compound classes including lipids, acids, pharmaceutical agents, signalling molecules, vitamins, among others. Phospholipids and carboxylic acids accounted for 28% of all detected compounds. Out of the 33 compounds significantly affected by collection tube, 18 compounds were higher in the Streck tubes, including allantoin and ketoleucine, and 15 were higher in the Heparin tubes, including LysoPC(P-16:0), PS 40:6, and chenodeoxycholic acid glycine conjugate. Based on our results, it is recommended that replicate blood samples from each patient should be collected in different types of blood collection tubes for a broader range of the metabolome. Several metabolites were found at higher concentrations in cancer patients such as lactic acid in Squamous Cell Carcinoma, and lysoPCs in Adenocarcinoma and Acinar Cell Carcinoma, which may be used to detect early onset and/or to monitor the progress of the cancer patients.

Serum or plasma? An old question looking for new answers

Serum or plasma? An old question looking for new answers. There is a continual debate on what type of sample a clinical laboratory should use. While serum is still considered the gold standard and remains the required sample for some assays, laboratories must consider turn-around time, which is an important metric for laboratory performance and, more importantly, plays a critical role in patient care. In addition, a body of evidence emphasise the choice of plasma in order to prevent modifications of some analytes due to the coagulation process and related interferences. Advantages and disadvantages of serum and plasma are discussed on the basis of current literature and evidence. In addition, data are provided on the current utilisation of the samples (serum or plasma) in Italy and in other countries. Finally, a rationale for a possible switch from serum to plasma is provided.

Platelet-rich fibrin: Basics of biological actions and protocol modifications

Platelet-rich fibrin (PRF) represents second generation of platelet concentrates, which has gained increasing awareness in recent years for regenerative procedures. This biologic additive is completely autologous, easy to prepare, has minimal expense, and possesses prolonged growth factor release, together with several other advantages over traditionally prepared platelet concentrates. Since its introduction, various protocols for PRF preparation have been proposed with different amounts of growth factors and other biomolecules necessary for wound healing. However, reference data about potential effect of some PRF components on hard and soft tissue healing are still conflicting. The current article intends to clarify the relevant advances about physiological role of certain PRF components and to provide insight into the new developmental approach. Also, this review summarizes the evolution of platelet concentrates and biologic properties of different modifications of PRF procedure.

Improved Sample Quality and Decreased Turnaround Time When Using Plasma Blood Collection Tubes with a Mechanical Separator in a Large University Hospital

BACKGROUND

Serum is commonly used for clinical chemistry testing but many conditions can affect the clotting process, leading to poor sample quality and impaired workflow. With serum gel tubes, we found a high proportion of sample probe aspiration errors on our Beckman AU5800 analyzers. We decided to implement the BD Barricor™ plasma tubes, and we validated an off-specification centrifugation scheme and verified that results obtained for 65 chemistry and immunochemistry tests were comparable to those obtained in serum gel tubes. Finally, we evaluated the impact of this new tube on sample error rate and laboratory turnaround time.

METHODS

To validate centrifugation settings, 50 paired samples were collected in Barricor tubes and centrifuged at 1912 × g for 10 min or 5 min (off-specification). To compare serum gel tubes with Barricor plasma tubes, 119 paired samples were collected from volunteers and results were analyzed using weighed Deming regression. Finally, the proportion of aspiration errors and laboratory TAT for potassium were measured before and after implementing Barricor tubes.

RESULTS

Barricor tubes showed clinically acceptable equivalence to serum gel tubes for the studied analytes, and the off-specification centrifugation scheme did not affect the results. Implementing Barricor tubes improved the laboratory workflow by decreasing the aspiration error rates (2.01% to 0.77%, P < 0.001) and lowering hemolysis (P < 0.001). The laboratory TAT for potassium were also significantly lowered (P < 0.001).

CONCLUSION

Use of Barricor tubes instead of serum gel tubes leads to better sample quality, shorter more reproducible laboratory TAT, and decreases costs associated with error management.

Contradictory Phenomenon Between Serum Separator Tube and Plasma Tube: A Case Report

Separator gels in blood collection tubes are used to separate serum from clotted whole blood or plasma from cells. Here we present a case of a patient with a contradictory phenomenon between the serum separator tube and the plasma tube. The serum separator tube showed mixed serum and separator gel and distinctly less serum. However, the plasma tube showed fewer cells. Laboratory study revealed an IgG level of 78.9 g/L. Serum immunofixation electrophoresis analysis identified the abnormal pattern as a dense IgG band with a corresponding dense light chain band of λ. Bone marrow smear showed 53% proplasmacytes. The patient was diagnosed with multiple myeloma. The marked hyperproteinemia, especially hyperimmunoglobulinemia, may have resulted in the density alteration of serum that was mixed or located above the separator gel. This phenomenon is also seen in patients injected with iodinated radiologic contrast media such as iohexol and in patients on hemodialysis with a concentrated sodium citrate solution.

Pseudothrombocytopenia-A Review on Causes, Occurrence and Clinical Implications

Pseudothrombocytopenia (PTCP), a relative common finding in clinical laboratories, can lead to diagnostic errors, overtreatment, and further (even invasive) unnecessary testing. Clinical consequences with potential life-threatening events (e.g., unnecessary platelet transfusion, inappropriate treatment including splenectomy or corticosteroids) are still observed when PTCP is not readily detected. The phenomenon is even more complex when occurring with different anticoagulants. In this review we present a case of multi-anticoagulant PTCP, where we studied different parameters including temperature, amikacin supplementation, measurement methods, and type of anticoagulant. Prevalence, clinical risk factors, pre-analytical and analytical factors, along with clinical implications, will be discussed. The detection of an anticoagulant-dependent PTCP does not necessarily imply the presence of specific disorders. Conversely, the incidence of PTCP seems higher in patients receiving low molecular weight heparin, during hospitalization, or in men aged 50 years or older. New analytical technologies, such as fluorescence or optical platelet counting, will be soon overturning traditional algorithms and represent valuable diagnostic aids. A practical laboratory approach, based on current knowledge of PTCP, is finally proposed for overcoming spuriously low platelet counts.

Affinity Proteomics Assays for Cardiovascular and Atherosclerotic Disease Biomarkers

Systematic exploration of the dynamic human plasma proteome enables the discovery of novel protein biomarkers. Using state-of-the-art technologies holds the promise to facilitate a better diagnosis and risk prediction of diseases. Cardiovascular disease (CVD) pathophysiology is characterized for unbalancing of processes such as vascular inflammation, endothelial dysfunction, or lipid profiles among others. Such processes have a direct impact on the dynamic and complex composition of blood and hence the plasma proteome. Therefore, the study of the plasma proteome comprises an excellent exploratory source of biomarker research particularly for CVD. We describe the protocol for performing the discovery of protein biomarker candidates using the suspension bead array technology. The process does not require depletion steps to remove abundant proteins and consumes only a few microliters of sample from the body fluid of interest. The approach is scalable to measure many analytes as well as large numbers of samples. Moreover, we describe a bead-assisted antibody-labeling process that helps to develop quantitative assays for validation purposes and facilitate the translation of the identified candidates into clinical studies.

Physiological implications of life at the forest interface of oil palm agriculture: blood profiles of wild Malay civets (Viverra tangalunga)

Agricultural development is a major threat to global biodiversity, and effective conservation actions are crucial. Physiological repercussions of life alongside human-modified landscapes can undermine adaptable species' health and population viability; however, baseline data are lacking for many wildlife species. We assessed the physiological status of a generalist carnivore, the Malay civet (Viverra tangalunga), persisting within an extensively human-modified system in Sabah, Malaysian Borneo. We characterized hematology and serum biochemistry panels from civets sampled across a mosaic landscape comprising tropical forest fragments and oil palm plantations. Intra-population variation in certain blood parameters were explained by expected biological drivers such as sex, age category and sampling season. Furthermore, we determined several erythrocyte measures, immune cell counts and dietary biochemistry markers significantly varied with proximity to oil palm plantation boundaries. These findings were supported by a case study, whereby blood profiles of GPS collared male civets were contrasted based on their exclusive use of forests or use of oil palm plantations. These data provide robust and valuable first insights into this species' physiological status and suggest agricultural landscapes are impacting the persisting population.

Diagnostic accuracy of a bovine specific electronic beta-hydroxybutyrate handheld meter in fresh blood and stored serum samples

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The nova vet handheld beta-hydroxybutyrate meter showed high accuracy and precision.

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Anticoagulants caused minimal interference in measurements.

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The best calibration factor on cattle was obtained with the default slope setting.

This study aims to evaluate the diagnostic accuracy of the bovine specific beta-hydroxybutyrate (BHB) meter Nova Vet (NVET). We evaluated the accuracy and agreement of the NVET in fresh blood and thawed serum with the reference laboratory assay; and the repeatability, the interference by anticoagulants, and the optimum slope calibration factor. Individual blood samples were collected from 200 Holstein and crossbred cows between 3 and 14 days post-calving from 13 dairy herds in Minnesota. Using a laboratory assay with a cut point of 1.2 BHB mmol/L hyperketonemia prevalence was 10.6% (95% CI: 6.7, 15.8). The sensitivity of NVET in blood and serum was 100.0% while the specificity was 98.3 and 97.7% respectively. The agreement between NVET and the laboratory assay was the highest using blood samples (concordance correlation coefficient –CCC = 96.2, 95% CI: 95.0, 97.1. The coefficient of variation including within day (intra-meter), between- days, and -batches was 13.4% when testing blood samples. Minimal interference was observed with the use of anticoagulants (K-EDTA and Li-Heparin, CCC 0.90 and 0.93 respectively) in reference to whole blood without anticoagulant. The best calibration slope factor in serum was 1.0 (Youden's index: 0.98). Results suggest that the NVET device maintained a high accuracy and precision to quantified BHB concentration when applied in fresh blood and thawed serum under field conditions using the default calibration slope (1.0), and with minimal anticoagulant interference when used in whole blood samples.

The influence of sodium citrate on the characteristics and biological activity of plasma rich in growth factors

Aim: This study investigated the effect of sodium citrate on the properties and biological activity of plasma rich in growth factors (PRGF). Methods: PRGF was obtained from trisodium citrate and plain extraction tubes. Hematological parameters, growth factors' release kinetics from both PRGF clots and their releasates' biological effect on human bone cells were evaluated. Results: The platelet enrichment factor, the growth factors' content and the release kinetic of PRGF were similar for both groups. The proliferation, collagen type I synthesis and tissue-nonspecific alkaline phosphatase activity of human osteoblasts showed no statistically significant differences. Conclusion: The use of sodium citrate does not influence the composition, the growth factors' release kinetics or the biological effect of PRGF, but it increases its clinical versatility.

Clot activators and anticoagulant additives for blood collection. A critical review on behalf of COLABIOCLI WG-PRE-LATAM

In the clinical laboratory, knowledge of and the correct use of clot activators and anticoagulant additives are critical to preserve and maintain samples in optimal conditions prior to analysis. In 2017, the Latin America Confederation of Clinical Biochemistry (COLABIOCLI) commissioned the Latin American Working Group for Preanalytical Phase (WG-PRE-LATAM) to study preanalytical variability and establish guidelines for preanalytical procedures to be applied by clinical laboratories and health care professionals. The aim of this critical review, on behalf of COLABIOCLI WG-PRE-LATAM, is to provide information to understand the mechanisms of the interactions and reactions that occur between blood and clot activators and anticoagulant additives inside evacuated tubes used for laboratory testing. Clot activators - glass, silica, kaolin, bentonite, and diatomaceous earth - work by surface dependent mechanism whereas extrinsic biomolecules - thrombin, snake venoms, ellagic acid, and thromboplastin - start in vitro coagulation when added to blood. Few manufacturers of evacuated tubes state the type and concentration of clot activators used in their products. With respect to anticoagulant additives, sodium citrate and oxalate complex free calcium and ethylenediaminetetraacetic acid chelates calcium. Heparin potentiates antithrombin and hirudin binds to active thrombin, inactivating the thrombin irreversibly. Blood collection tubes have improved continually over the years, from the glass tubes containing clot activators or anticoagulant additives that were prepared by laboratory personnel to the current standardized evacuated systems that permit more precise blood/additive ratios. Each clot activator and anticoagulant additive demonstrates specific functionality, and both manufacturers of tubes and laboratory professional strive to provide suitable interference-free sample matrices for laboratory testing. Both manufacturers of in vitro diagnostic devices and laboratory professionals need to understand all aspects of venous blood sampling so that they do not underestimate the impact of tube additives on laboratory testing.

A comparative analysis of different biofluids towards ovarian cancer diagnosis using Raman microspectroscopy

Biofluids, such as blood plasma or serum, are currently being evaluated for cancer detection using vibrational spectroscopy. These fluids contain information of key biomolecules, such as proteins, lipids, carbohydrates and nucleic acids, that comprise spectrochemical patterns to differentiate samples. Raman is a water-free and practically non-destructive vibrational spectroscopy technique, capable of recording spectrochemical fingerprints of biofluids with minimum or no sample preparation. Herein, we compare the performance of these two common biofluids (blood plasma and serum) together with ascitic fluid, towards ovarian cancer detection using Raman microspectroscopy. Samples from thirty-eight patients were analysed (n = 18 ovarian cancer patients, n = 20 benign controls) through different spectral pre-processing and discriminant analysis techniques. Ascitic fluid provided the best class separation in both unsupervised and supervised discrimination approaches, where classification accuracies, sensitivities and specificities above 80% were obtained, in comparison to 60–73% with plasma or serum. Ascitic fluid appears to be rich in collagen information responsible for distinguishing ovarian cancer samples, where collagen-signalling bands at 1004 cm⁻¹ (phenylalanine), 1334 cm⁻¹ (CH₃CH₂ wagging vibration), 1448 cm⁻¹ (CH₂ deformation) and 1657 cm⁻¹ (Amide I) exhibited high statistical significance for class differentiation (P < 0.001). The efficacy of vibrational spectroscopy, in particular Raman spectroscopy, combined with ascitic fluid analysis, suggests a potential diagnostic method for ovarian cancer.

Feasibility and safety study of 22-gauge endoscopic ultrasound (EUS) needles for portal vein sampling in a swine model

Background and study aims  Endoscopic ultrasound (EUS) has been used for portal vein sampling in patients with pancreaticobiliary cancers for enumerating circulating tumor cells but is not yet a standard procedure. Further evaluation is needed to refine the methodology. Therefore, we evaluated the feasibility and safety of 19-gauge (19G) versus a 22-gauge (22 G) EUS fine-needle aspiration needles for portal vein sampling in a swine model. Methods  Celiotomy was performed on two farm pigs. Portal vein sampling occurred transhepatically. We compared 19 G and 22 G needles coated interiorly with saline, heparin or ethylenediaminetetraacetic acid (EDTA). Small- (10 mL) and large- (25 mL) volume blood collections were evaluated. Two different collection methods were tested: direct-to-vial and suction syringe. A bleeding risk trial for saline-coated 19 G and 22 G needles was performed by puncturing the portal vein 20 times. Persistent bleeding after 3 minutes was considered significant. Results  All small-volume collection trials were successful except for 22 G saline-coated needles with direct-to-vial method. All large-volume collection trials were successful when using suction syringe; direct-to-vial method for both 19 G and 22 G needles were unsuccessful. Collection times were shorter for 19 G vs. 22 G needles for both small and large-volume collections ( P  < 0.05). Collection times for saline-coated 22 G needles were longer compared to heparin/EDTA-coated ( P  < 0.05). Bleeding occurred in 10 % punctures with 19 G needles compared to 0 % with 22 G needles. Conclusion  The results of this animal study demonstrate the feasibility and the safety of using 22 G needles for portal vein sampling and can form the basis for a pilot study in patients.

Evaluation of the Abbot FreeStyle Optium Neo H blood glucose meter in the hyperbaric oxygen environment

INTRODUCTION

This study investigated the effects of hyperbaric oxygen treatment (HBOT) on the accuracy and reliability of point-of-care fingertip capillary blood glucose values in euglycaemic non-diabetic participants compared against venous serum blood glucose samples processed in an accredited pathology laboratory.

METHOD

Ten non-diabetic hyperbaric staff members (age 35-55 years) underwent a standard 243 kPa HBOT exposure for 95 minutes. Blood glucose levels were measured via (i) finger-prick capillary test using the FreeStyle Optium™ Neo H glucometer and (ii) venous serum test using the Cobas 6000 laboratory analyser. Samples were taken at (T1) 0 minutes (pre-HBOT), (T2) 25 minutes, and (T3) 55 minutes into HBOT.

RESULTS

All participants were euglycaemic at T1 (BGL 3.8-5.4 mmol·L⁻¹). The highest venous serum value was 5.90 mmol·L⁻¹ at T3 and the highest capillary value was 6.30 mmol·L⁻¹ at T1. Post hoc tests showed a statistically significant difference between the mean capillary result pre-dive (T1) and readings at T2 (P = 0.001) and T3 (P < 0.001) while differences between T2 and T3 capillary results were not statistically significant, illustrating the effect of HBOT on capillary beds. Differences in venous values across the time points were not significant.

CONCLUSION

Venous serum glucose samples processed in an accredited laboratory may be more consistently accurate, but capillary point-of-care testing avoids delays in sample processing and provides glucose data that are of clinical relevance. The FreeStyle Optium™ Neo H glucometer is safe to use and provides a reliable measurement of blood glucose in the HBOT environment.

Methodological variations affect the release of VEGF in vitro and fibrinolysis' time from platelet concentrates

Blood Concentrates (BCs) are autologous non-transfusional therapeutical preparations with biological properties applied in tissue regeneration. These BCs differ in the preparation method, in fibrin network architecture, growth factors release as well as in platelet/cell content. Methodological changes result in distinct matrices that can compromise their clinical effectiveness. The present study evaluated the influence of different g-forces and types of tubes in the release of vascular endothelial growth factor (VEGF) from platelet-rich fibrin (PRF) as a function of time. The PRF-like samples were obtained with three g-forces (200, 400, and 800 x g) for 10 minutes in pure glass tubes or in polystyrene-clot activator tubes. Scanning and Transmission electron microscopy was used to morphometric analyzes of PRF’s specimens and flow cytometry was used to quantify VEGF slow release until 7 days. Our results showed that platelets were intact and adhered to the fibrin network, emitting pseudopods and in degranulation. The fibrin network was rough and twisted with exosomic granulations impregnated on its surface. An increase in the concentration of VEGF in the PRF supernatant was observed until 7 days for all g forces (200, 400 or 800 xg), with the highest concentrations observed with 200 x g, in both tubes, glass or plastic. Morphological analyzes showed a reduction in the diameter of the PRF fibers after 7 days. Our results showed that g-force interferes with the shape of the fibrin network in the PRF, as well as affect the release of VEGF stored into platelets. This finding may be useful in applying PRF to skin lesions, in which the rapid release of growth factors can favor the tissue repair process. Our observations point to a greater clarification on the methodological variations related to obtaining PRF matrices, as they can generate products with different characteristics and degrees of effectiveness in specific applications.

Stability of complete blood count parameters depends on the storage temperature, storage time, transport position and selected stability criterion

Purpose: To evaluate stability of CBC parameters in samples containing K₃-EDTA in Hema&Tube brand evacuated tubes stored at 4 °C and room temperature in upright, horizontal and upside-down transport positions for up to 240 min by comparing with different stability criteria. Methods: A total of 450 outpatient samples, 75 for each condition, were stored for 240 min. Blood samples were analyzed at baseline, 60th, 120th and 240th min of storage time using Sysmex® XT-4000i hematology analyzer. CBC results were compared according to the paired samples t-test, one CV% change, CVI, BV DES 2014, RCPA, IQMH, EFLM Biological Variation 2019, ESfEQAand CLIA stability criteria. Results: In all transport conditions, almost all CBC parameters were unstable according to the paired samples t-test. Based on one CV % change RBC, hemoglobin, hematocrit, RDW-CV, neutrophils, platelets, MPV, PDW and plateletcrit were unstable in some transport conditions. However, most parameters were stable at all conditions, except especially for MCH, MPV, PDW and plateletcrit, while just MPV and PDW were unstable at RT in all transport conditions according to the lower and higher CVI, respectively. Conclusions: Paired samples t-test and one CV% change stability criteria are not suitable for decision. Clinical laboratories should establish the impact of storage time, storage temperature and transport positions for each CBC parameter while paying attention to the brand of evacuated tube according to the lower CVI of biological variation data stability criteria since it is more related to the impact of analysis deviation on clinical decisions to prevent misdiagnosis.

Vitamin D Metabolism and Profiling in Veterinary Species

The demand for vitamin D analysis in veterinary species is increasing with the growing knowledge of the extra-skeletal role vitamin D plays in health and disease. The circulating 25-hydroxyvitamin-D (25(OH)D) metabolite is used to assess vitamin D status, and the benefits of analysing other metabolites in the complex vitamin D pathway are being discovered in humans. Profiling of the vitamin D pathway by liquid chromatography tandem mass spectrometry (LC-MS/MS) facilitates simultaneous analysis of multiple metabolites in a single sample and over wide dynamic ranges, and this method is now considered the gold-standard for quantifying vitamin D metabolites. However, very few studies report using LC-MS/MS for the analysis of vitamin D metabolites in veterinary species. Given the complexity of the vitamin D pathway and the similarities in the roles of vitamin D in health and disease between humans and companion animals, there is a clear need to establish a comprehensive, reliable method for veterinary analysis that is comparable to that used in human clinical practice. In this review, we highlight the differences in vitamin D metabolism between veterinary species and the benefits of measuring vitamin D metabolites beyond 25(OH)D. Finally, we discuss the analytical challenges in profiling vitamin D in veterinary species with a focus on LC-MS/MS methods.

The impact of pre-analytical variations on biochemical analytes stability: A systematic review

Objective

A common problem in clinical laboratories is maintaining the stability of analytes during pre‐analytical processes. The aim of this study was to systematically summarize the results of a set of studies about the biochemical analytes stability.

Methods

A literature search was performed on the Advanced search field of PubMed using the keywords: “(stability) AND (analytes OR laboratory analytes OR laboratory tests OR biochemical analytes OR biochemical tests OR biochemical laboratory tests).” A total of 56 entries were obtained. After applying the selection criteria, 20 articles were included in the study.

Results

In the 20 included references, up to 123 different analytes were assessed. The 34 analytes in order of the most frequently studied analytes were evaluated: Alanine aminotransferase, aspartate aminotransferase, potassium, triglyceride, alkaline phosphatase, creatinine, total cholesterol, albumin, lactate dehydrogenase, sodium, calcium, γ‐glutamyltransferase, total bilirubin, urea, creatine kinase, inorganic phosphate, total protein, uric acid, amylase, chloride, high‐density lipoprotein, magnesium, glucose, C‐reactive protein, bicarbonate, ferritin, iron, lipase, transferrin, cobalamin, cortisol, folate, free thyroxine, and thyroid‐stimulating hormone. Stable test results could be varied between 2 hours and 1 week according to the type of samples and/or type of blood collection tubes on a basic classification set as refrigerated or room temperature.

Conclusions

Biochemical analytes stability could be improved if the best pre‐analytical approaches are used.

EDTA-Anticoagulated Whole Blood for SARS-CoV-2 Antibody Testing by Electrochemiluminescence Immunoassay (ECLIA) and Enzyme-Linked Immunosorbent Assay (ELISA)

While lateral flow test formats can be utilized with whole blood and low sample volumes, their diagnostic characteristics are inferior to immunoassays based on chemiluminescence immunoassay (CLIA) or enzyme-linked immunosorbent assay (ELISA) technology. CLIAs and ELISAs can be automated to a high degree but commonly require larger serum or plasma volumes for sample processing. We addressed the suitability of EDTA-anticoagulated whole blood as an alternative sample material for antibody testing against SARS-CoV-2 by electro-CLIA (ECLIA; Roche, Rotkreuz, Switzerland) and ELISA (IgG and IgA; Euroimmun, Germany). Simultaneously drawn venous serum and EDTA-anticoagulated whole blood samples from 223 individuals were included. Correction of the whole blood results for hematocrit led to a good agreement with the serum results for weakly to moderately positive antibody signals. In receiver-operating characteristic curve analysis, all three assays displayed comparable diagnostic accuracy (area under the curve (AUC)) using corrected whole blood and serum (AUCs: 0.97 for ECLIA and IgG ELISA; 0.84 for IgA ELISA). In conclusion, our results suggest that the investigated assays can reliably detect antibodies against SARS-CoV-2 in hemolyzed whole blood anticoagulated with EDTA. Correction of these results for hematocrit is suggested. This study demonstrates that the automated processing of whole blood for identification of SARS-CoV-2 antibodies with common ECLIA and ELISA methods is accurate and feasible.

Comparison of 2 portable human glucometers for the measurement of blood glucose concentration in White New Zealand rabbits

We compared measurements of blood glucose concentrations in 30 healthy adult White New Zealand rabbits using 2 commercial portable glucometers (PGM1 and PGM2) and a laboratory chemical analyzer. Results were analyzed with Pearson correlation, Passing-Bablok regression analysis, Bland-Altman analysis, and a modified error grid. Measurements with PGM1 were significantly correlated (r = 0.37) with those obtained from the laboratory reference method (RM); Bland-Altman and Passing-Bablok analyses indicated no significant systematic or proportional differences (mean difference of -0.26, 95% CI of mean difference of -0.54 to 0.01, and LOA of -1.70 to 1.17); and error grid resulted in 100% of measurements in zone A. No significant correlation (r = -0.05) was detected between PGM2 and RM; Bland-Altman and Passing-Bablok analyses results indicated a mean difference of 2.14, 95% CI of mean difference of 1.67-2.60, and limit of agreement of -0.32 to 4.59, which overestimated blood glucose concentration, with 53% of glucose measurements in error grid zone A and 47% in zone B. PGM1 was considered accurate in normoglycemic rabbits, whereas the use of PGM2 could result in overestimations of glycemia.

Antimicrobial Susceptibility Testing of Antimicrobial Peptides to Better Predict Efficacy

During the development of antimicrobial peptides (AMP) as potential therapeutics, antimicrobial susceptibility testing (AST) stands as an essential part of the process in identification and optimisation of candidate AMP. Standard methods for AST, developed almost 60 years ago for testing conventional antibiotics, are not necessarily fit for purpose when it comes to determining the susceptibility of microorganisms to AMP. Without careful consideration of the parameters comprising AST there is a risk of failing to identify novel antimicrobials at a time when antimicrobial resistance (AMR) is leading the planet toward a post-antibiotic era. More physiologically/clinically relevant AST will allow better determination of the preclinical activity of drug candidates and allow the identification of lead compounds. An important consideration is the efficacy of AMP in biological matrices replicating sites of infection, e.g., blood/plasma/serum, lung bronchiolar lavage fluid/sputum, urine, biofilms, etc., as this will likely be more predictive of clinical efficacy. Additionally, specific AST for different target microorganisms may help to better predict efficacy of AMP in specific infections. In this manuscript, we describe what we believe are the key considerations for AST of AMP and hope that this information can better guide the preclinical development of AMP toward becoming a new generation of urgently needed antimicrobials.

A Multicenter Evaluation of a Nongel Mechanical Separator Plasma Blood Collection Tube for Testing of Selected Therapeutic Drugs

BACKGROUND

Some therapeutic drugs are unstable during sample storage in gel tubes. BD Vacutainer® Barricor™ Plasma Blood Collection Tube with nongel separator was compared with plasma gel tubes, BD Vacutainer PST™, PST II, and BD Vacutainer Serum Tube for acetaminophen, salicylate, digoxin, carbamazepine, phenytoin, valproic acid, and vancomycin during sample storage for up to 7 days.

METHODS

Seven hospital sites enrolled 705 participants who were taking at least one selected drug. The study tubes were collected and tested at initial time (0 h), after 48 h of storage at room temperature and on day 7 (after additional 5 days of refrigerated storage). The performance of BD Barricor tube was evaluated for each drug by comparing BD Barricor samples with samples from the other tubes at 0 h from the same participant; stability was evaluated by comparing test results from the same tube at 0 h, 48 h, and 7 days.

RESULTS

At 0 h, BD Barricor showed clinically equivalent results for selected therapeutic drugs compared with the other tubes, except phenytoin in BD PST. Phenytoin samples ≥20 µg/mL in BD PST had 10-12% lower values than samples in BD Barricor. During sample storage, all selected drugs remained stable for 7 days in BD Barricor and in serum aliquots. In BD PST, all drugs remained stable except phenytoin and carbamazepine and in BD PST II except for phenytoin.

CONCLUSION

The BD Barricor Tube is effective for the collection and storage of plasma blood samples for therapeutic drug monitoring without sample aliquoting.

A Review of Efforts to Improve Lipid Stability during Sample Preparation and Standardization Efforts to Ensure Accuracy in the Reporting of Lipid Measurements

Lipidomics is a rapidly growing field, fueled by developments in analytical instrumentation and bioinformatics. To date, most researchers and industries have employed their own lipidomics workflows without a consensus on best practices. Without a community-wide consensus on best practices for the prevention of lipid degradation and transformations through sample collection and analysis, it is difficult to assess the quality of lipidomics data and hence trust results. Clinical studies often rely on samples being stored for weeks or months until they are analyzed, but inappropriate sampling techniques, storage temperatures, and analytical protocols can result in the degradation of complex lipids and the generation of oxidized or hydrolyzed metabolite artifacts. While best practices for lipid stability are sample dependent, it is generally recommended that strategies during sample preparation capable of quenching enzymatic activity and preventing oxidation should be considered. In addition, after sample preparation, lipid extracts should be stored in organic solvents with antioxidants at -20 °C or lower in an airtight container without exposure to light or oxygen. This will reduce or eliminate sublimation, and chemically and physically induced molecular transformations such as oxidation, enzymatic transformation, and photon/heat-induced degradation. This review explores the available literature on lipid stability, with a particular focus on human health and/or clinical lipidomic applications. Specifically, this includes a description of known mechanisms of lipid degradation, strategies, and considerations for lipid storage, as well as current efforts for standardization and quality insurance of protocols.

Recommendations and Best Practices for Standardizing the Pre-Analytical Processing of Blood and Urine Samples in Metabolomics

Metabolomics can be significantly influenced by a range of pre-analytical factors, such as sample collection, pre-processing, aliquoting, transport, storage and thawing. This therefore shows the crucial need for standardizing the pre-analytical phase with the aim of minimizing the inter-sample variability driven by these technical issues, as well as for maintaining the metabolic integrity of biological samples to ensure that metabolomic profiles are a direct expression of the in vivo biochemical status. This review article provides an updated literature revision of the most important factors related to sample handling and pre-processing that may affect metabolomics results, particularly focusing on the most commonly investigated biofluids in metabolomics, namely blood plasma/serum and urine. Finally, we also provide some general recommendations and best practices aimed to standardize and accurately report all these pre-analytical aspects in metabolomics research.

Serum outperforms plasma in small extracellular vesicle microRNA biomarker studies of adenocarcinoma of the esophagus

BACKGROUND

Circulating microRNAs (miRNAs) are potential biomarkers for many diseases. However, they can originate from non-disease specific sources, such as blood cells, and compromise the investigations for miRNA biomarkers. While small extracellular vesicles (sEVs) have been suggested to provide a purer source of circulating miRNAs for biomarkers discovery, the most suitable blood sample for sEV miRNA biomarker studies has not been defined.

AIM

To compare the miRNA profiles between matched serum and plasma sEV preparations to determine their suitability for biomarker studies.

METHODS

Matched serum and plasma samples were obtained from 10 healthy controls and 10 patients with esophageal adenocarcinoma. sEV isolates were prepared from serum and plasma using ExoQuick^TM and quantified using NanoSight. RNA was extracted from sEV preparations with the miRNeasy Serum/Plasma kit and profiled using the Taqman Openarray qPCR. The overall miRNA content and the expression of specific miRNAs of reported vesicular and non-vesicular origins were compared between serum and plasma sEV preparations. The diagnostic performance of a previously identified multi-miRNA biomarker panel for esophageal adenocarcinoma was also compared.

RESULTS

The overall miRNA content was higher in plasma sEV preparations (480 miRNAs) and contained 97.5% of the miRNAs found in the serum sEV preparations (412 miRNAs).The expression of commonly expressed miRNAs was highly correlated (Spearman’s R = 0.87, P < 0.0001) between the plasma and serum sEV preparations, but was consistently higher in the plasma sEV preparations. Specific blood-cell miRNAs (hsa-miR-223-3p, hsa-miR-451a, miR-19b-3p, hsa-miR-17-5p, hsa-miR-30b-5p, hsa-miR-106a-5p, hsa-miR-150-5p and hsa-miR-92a-3p) were expressed at 2.7 to 9.6 fold higher levels in the plasma sEV preparations compared to serum sEV preparations (P < 0.05). In plasma sEV preparations, the percentage of protein-associated miRNAs expressed at relatively higher levels (Ct 20-25) was greater than serum sEV preparations (50% vs 31%). While the percentage of vesicle-associated miRNAs expressed at relatively higher levels was greater in the serum sEV preparations than plasma sEV preparations (70% vs 44%). A 5-miRNA biomarker panel produced a higher cross validated accuracy for discriminating patients with esophageal adenocarcinoma from healthy controls using serum sEV preparations compared with plasma sEV preparations (AUROC 0.80 vs 0.54, P < 0.05).

CONCLUSION

Although plasma sEV preparations contained more miRNAs than serum sEV preparations, they also contained more miRNAs from non-vesicle origins. Serum appears to be more suitable than plasma for sEV miRNAs biomarkers studies.

Hybrid Blood Collection Tubes: Combining the Best Attributes of Glass and Plastic for Safety and Shelf life

SiO₂ Medical Products, Inc. developed hybrid blood collection tubes (BCTs) that combine the breakage resistance of plastic and a shelf life approaching that of glass. These blended attributes provide improved BCT safety and reliability for patients and clinical workers. A shelf life of at least 2 y with less than 10% draw volume variation was demonstrated on evacuated hybrid BCTs, which is approximately 7 times longer than standard polyethylene terephthalate (PET) BCTs. This translates into more consistent and reliable blood draw volumes over a longer shelf life. The moisture vapor barrier of hybrid BCTs is 5 times lower than that of PET BCTs, which significantly reduces preservative evaporation over their shelf life. As a result, the risk of preservative gelation and alteration to the blood-to-preservative ratio mix is practically eliminated. Cyclic olefin polymer (COP) exhibits superior impact resistance to breakage because of its high ductility and impact strength and is not influenced by defects and flaws as is glass. Although COP has a mechanical toughness comparable with that of PET, it maintains this over a wider range of temperatures (–70 to 121 °C). As a result, COP can tolerate steam sterilization and cold storage temperatures without mechanical fatigue, deformation, or breakage. Lastly, extreme centrifugation of water-filled BCTs did not impose breakage of any kind.

Analytical performance of thrombospondin-1 and cathepsin D immunoassays part of a novel CE-IVD marked test as an aid in the diagnosis of prostate cancer

The Prostate Specific Antigen (PSA) test suffers from low specificity for the diagnosis of Prostate Cancer (PCa). We originally discovered two cancer-related proteins thrombospondin-1 (THBS1) and cathepsin D (CTSD) using a mass-spectrometry-based proteomics approach. The two serum proteins were shown to improve the diagnosis of high-grade PCa. Thus, we developed quantitative ELISAs for the determination of their concentration in human serum. Here we report their analytical performance in terms of limit of detection, specificity, precision, linearity and interferences, which were determined based on CLSI guidelines. Further, we investigated the influence of pre-analytical factors on concentration measurements. For this, blood from 4-6 donors was collected in different tubes and stored at room temperature for different times prior to centrifugation at different centrifugal forces and temperatures. Stability of THBS1 and CTSD under different storage temperatures was also evaluated. Our results show that the assays are specific, linear and sensitive enough to allow measurement of clinical samples. Precision in terms of repeatability and total within-laboratory coefficient of variation (CV) are 5.5% and 8.1% for THBS1 and 4.3% and 7.2% for CTSD, respectively. Relative laboratory-to-laboratory differences were -6.3% for THBS1 and -3% for CTSD. Both THBS1 and CTSD were stable in serum samples, with 80-120% recoveries of concentrations across donors, sample preparation and storage. In conclusion, the ELISAs as part of the novel commercial in vitro diagnostic test Proclarix are suitable for the use in clinical practice. THBS1 and CTSD can be accurately measured for their intended use independent of the lot and laboratory when conditions consistent with routine practice for PSA sampling and storage are used.

New Tests in Feline Veterinary Medicine: When to Use Them and When to Stick with Tried-and-True Tests

The focus of this article is on how interpretations of laboratory data can utilize both population and individual reference intervals, while making the most of routine testing procedures coupled with some of the newer laboratory tests, which can complement the existing tests in diagnosing disease.

Neuro biomarker levels measured with high-sensitivity digital ELISA differ between serum and plasma

Aim: Digital ELISA-based assays for blood biomarkers of neurological disease are on the verge of clinical use. Here, we aimed to determine whether different preanalytical blood processing techniques influence results. Materials & methods: Concentrations of neurofilament light chain (NfL), Tau and amyloid beta (Aβ) were measured in human plasma and serum specimens using digital ELISA and compared between blood products. Measured levels of NfL were highly equivalant between serum and plasma in all analyses, however, measured levels of Tau and Aβ were consistently lower in serum relative to plasma. Conclusion: Tau and Aβ are likely lost during clotting in serum preparations, and should be assayed in plasma to get an accurate measure of circulating levels.

Quality Control of Immunophenotyping

Applications of immunophenotyping using flow cytometry offer precise and accurate means for providing information used to both diagnose and monitor disease; they serve as a standard platform for many research endeavors that study discrete populations of biological entities. The proper use of this highly sophisticated technology requires daily and ongoing monitoring of both the instrument and the methodology. Best practices for this begin with quality control (QC) procedures designed to set up and monitor the instrument performance, the reagents, and the results to ensure that they are working properly both on the day of use and over time. If the results of those QC procedures are outside of acceptable then recording the corrective action taken must also be included in the quality control records. Quality assurance (QA) is a way to know that the three phases of testing, namely, preanalytic, analytic, and postanalytic procedures, are being followed. This chapter describes the procedures used to assess quality control as it pertains to flow cytometry and immunophenotyping in all three phases of testing.

Peripheral biomarkers of mitochondrial dysfunction in adolescents with bipolar disorder

BACKGROUND

Mitochondrial dysfunction has been implicated in the pathophysiology of bipolar disorder (BD). Impediment of mitochondrial oxidative phosphorylation results in a shift toward anaerobic respiration and lactate production. Elevated CNS lactate levels in adults with BD inform the need to evaluate lactate in peripheral samples and early in the course of BD. Furthermore, there exists a recent surge of investigations looking at circulating cell-free mitochondrial DNA (ccf-mtDNA) as a potential biomarker as they are released from cells under physiological stress, apoptosis, or bioenergetic compromise.

OBJECTIVES

To compare lactate and ccf-mtDNA, two different ways in assessing the mitochondrial health and function, in adolescents with BD versus healthy control adolescents (HC).

METHODS

One-hundred and five adolescents (n = 64 BD, n = 41 HC) were included. Serum lactate level was measured using a commercially available colorimetric kit. Serum ccf-mtDNA concentration was measured using quantitative polymerase chain reaction from ccfDNA purified by commercially available spin columns. Diagnosis and mood symptoms were evaluated using semi-structured interviews.

RESULTS

There is an increase in serum lactate level of adolescents with BD (1.319 ± 0.444 nmol/uL) versus HC (1.168 ± 0.353 nmol/uL; p = 0.043), but not ccf-mtDNA. Among BD adolescents, depression symptoms were negatively correlated with ccf-mtDNA levels (ρ = -0.289; p = 0.038) but loses significance when corrected for multiple comparison. Lactate was positively correlated with ccf-mtDNA in the overall sample (ρ = 0.201; p = 0.043). When examined by diagnosis, this association remained in BD (ρ = 0.273; p = 0.032), but not HC.

CONCLUSION

These preliminary results indicate that elevated lactate is observed even among adolescents early in their course of BD, that the association between lactate and ccf-mtDNA appears to be specific to BD, and that ccf-mtDNA is potentially associated with depression symptoms in adolescent BD. In addition, the effect of psychotropic medications used in the treatment of BD on peripheral lactate and ccf-mtDNA requires further investigation.

Development of a Cell-Based Assay for the Detection of Neutralizing Antibodies to PF-06730512 Using Homogenous Time-Resolved Fluorescence

The administration of biotherapeutics has the potential to induce potent immune responses. Among these responses, the production of anti-drug antibodies (ADA), including a subset of ADA referred to as neutralizing antibodies (NAb), is of heightened concern. Aside from their capacity to alter the pharmacological profile of a given biotherapeutic, NAb can also pose significant safety risks, especially in instances where an endogenous counterpart to the drug exists. As such, the inclusion of an assay to detect NAb in clinical samples is critical to the effectiveness of a tiered approach to immunogenicity assessment. PF-06730512 is a biotherapeutic protein being developed for the treatment of primary Focal Segmental Glomerulosclerosis (FSGS). To support the immunogenicity assessment of PF-06730512, a cell-based assay was developed for the detection of NAb in FSGS serum samples. Herein, we describe the development of the assay with a focus on the challenges faced, including drug and blood collection tube interferences in NAb detection. The outcome of our efforts was a robust assay capable of detecting 1 μg/mL of a NAb positive control in the presence of clinically relevant drug concentrations up to 30 μg/mL.

Causes of Preanalytical Interferences on Laboratory Immunoassays - A Critical Review

The immunoassays methods need avoiding interferences that can influence result interpretation. Main sources of interference arise from either patient status, preparation and physiology or laboratory process and procedures. The aim of this non-systematic critical review is to highlight the preanalytical interferences on laboratory immunoassays. Blood hormone profile changes according with age and depending on sex: these are important variables, mainly in newborn, during both sexual maturation and childbearing. Gonadotropins FSH and LH show a sharp increase with age in females, whereas in males LH appears rather stable. With age both males and females show progressive decay of the hormone profile. Stress causes variations, as it influences GH, prolactin, Cortisol and the total/free ratio of thyroid hormone. Diurnal variations, day of cycle, influence by estrogens on thyroid hormone are relevant for result variability. Paraproteins and autoantibodies can interfere in some assays particularly drug, vitamin D and thyroid hormone. As regards the variables due to sample matrix, and to evacuated tubes components, some additives and anticoagulants have been reported to influence specific assays, e.g. thyroid hormone. Hemolysis, lipemia and bilirubin cause interferences on specific techniques/tests, e.g. ferritin, TSH, Vitamin B12, progesterone and folic acid. Nicotine and cocaine addictions interfere with some hormones. Thus, laboratory professionals should be aware of preanalytical problems particularly important when dealing with the immunoassays, by taking appropriate actions to avoid any relevant interferences.

Bladder cancer: total antioxidant capacity and pharmacotherapy with vitamin-E

PURPOSE

Free radicals play an important role in the different complex course of carcinogenesis. Higher concentrations of reactive oxygen species are highly associated with the presence of tumors. The urinary bladder organ is also a target for many carcinogens. The major objective of this investigation was to measure the role of redox state or total antioxidant capacity (T-AOC) and antioxidant functions of vitamin E in patients with low-grade papillary cancer of the bladder (BC).

METHODS

The blood sample was used for measurement of the T-AOC by the Trolox-TAC assay kit. Thirty-five patients with BC and thirty-five healthy subjects that matched for age were entered in this study. The obtained data were analyzed using the Statistical Package (SPSS Inc, Chicago, IL, USA). The significance level was set at p ≤ 0.05.

RESULTS

In healthy controls, the mean ± SD for T-AOC was 91.8 ± 16.6 (U/ml), that was significantly higher when compared to the mean value of 24.5 ± 28.9 (U/ml) in patients with BC (p = 0.00). The difference in concentration of T-AOC before and after prescription of vitamin E was encountered with a p value of 0.16.

CONCLUSIONS

By reference to the significant difference between T-AOC in patients and healthy controls, our results strongly suggest a low level of T-AOC in patients with BC. The obtained changes in T-AOC before and after management with vitamin E recommended additional consideration associates with different stages and grade of tumor in patients with BC.

Considerations for Soluble Protein Biomarker Blood Sample Matrix Selection

Blood-based soluble protein biomarkers provide invaluable clinical information about patients and are used as diagnostic, prognostic, and pharmacodynamic markers. The most commonly used blood sample matrices are serum and different types of plasma. In drug development research, the impact of sample matrix selection on successful protein biomarker quantification is sometimes overlooked. The sample matrix for a specific analyte is often chosen based on prior experience or literature searches, without good understanding of the possible effects on analyte quantification. Using a data set of 32 different soluble protein markers measured in matched serum and plasma samples, we examined the differences between serum and plasma and discussed how platelet or immune cell activation can change the quantified concentration of the analyte. We have also reviewed the effect of anticoagulant on analyte quantification. Finally, we provide specific recommendations for biomarker sample matrix selection and propose a systematic and data-driven approach for sample matrix selection. This review is intended to raise awareness of the impact and considerations of sample matrix selection on biomarker quantification.

"Lipidomics": Mass spectrometric and chemometric analyses of lipids

Lipids are ubiquitous in the human organism and play essential roles as components of cell membranes and hormones, for energy storage or as mediators of cell signaling pathways. As crucial mediators of the human metabolism, lipids are also involved in metabolic diseases, cardiovascular and renal diseases, cancer and/or hepatological and neurological disorders. With rapidly growing evidence supporting the impact of lipids on both the genesis and progression of these diseases as well as patient wellbeing, the characterization of the human lipidome has gained high interest and importance in life sciences and clinical diagnostics within the last 15 years. This is mostly due to technically advanced molecular identification and quantification methods, mainly based on mass spectrometry. Mass spectrometry has become one of the most powerful tools for the identification of lipids. New lipidic mediators or biomarkers of diseases can be analysed by state-of-the art mass spectrometry techniques supported by sophisticated bioinformatics and biostatistics. The lipidomic approach has developed dramatically in the realm of life sciences and clinical diagnostics due to the available mass spectrometric methods and in particular due to the adaptation of biostatistical methods in recent years. Therefore, the current knowledge of lipid extraction methods, mass-spectrometric approaches, biostatistical data analysis, including workflows for the interpretation of lipidomic high-throughput data, are reviewed in this manuscript.

EUS-Guided Portal Venous Sampling of Circulating Tumor Cells

PURPOSE OF REVIEW

Although liquid biopsies hold significant promise in the management of patients with cancer, peripheral blood analyses remain dependent on the degree of tumor burden with prohibitively low yields until the cancer is widely metastatic. Multiple lines of evidence support a dynamic, spatiotemporal localization of circulating tumor cells (CTCs) supporting specific targeting of vascular compartments, such as the portal vein. This review discusses the literature evaluating the possibility of portal venous blood as a new, potentially higher yield liquid biopsy and the current devices and techniques for endoscopic ultrasound (EUS)-guided portal venous sampling for CTC detection.

RECENT FINDINGS

Two recent studies in pancreatic cancer have demonstrated that portal venous blood can be safely sampled via EUS and consistently yields significantly higher CTC counts compared with matched peripheral blood. EUS-acquired samples can be used for molecular testing, clinical prognostication, and drug sensitivity analyses. Portal venous CTCs are identified in higher quantity relative to peripheral blood and can be safely obtained via EUS. Further studies are required to demonstrate the clinical utility of EUS-guided portal venous tumor material enrichment and analysis; however, obtaining EUS-guided "liquid biopsies" appears to merit significant consideration for procedural adoption.

Metabolic Profiling of Human Plasma and Urine, Targeting Tryptophan, Tyrosine and Branched Chain Amino Acid Pathways

Tryptophan and tyrosine metabolism has a major effect on human health, and disorders have been associated with the development of several pathologies. Recently, gut microbial metabolism was found to be important for maintaining correct physiology. Here, we describe the development and validation of a UHPLC-ESI-MS/MS method for targeted quantification of 39 metabolites related to tryptophan and tyrosine metabolism, branched chain amino acids and gut-derived metabolites in human plasma and urine. Extraction from plasma was optimised using 96-well plates, shown to be effective in removing phospholipids. Urine was filtered and diluted ten-fold. Metabolites were separated with reverse phase chromatography and detected using triple quadrupole MS. Linear ranges (from ppb to ppm) and correlation coefficients (r² > 0.990) were established for both matrices independently and the method was shown to be linear for all tested metabolites. At medium spiked concentration, recovery was over 80% in both matrices, while analytical precision was excellent (CV < 15%). Matrix effects were minimal and retention time stability was excellent. The applicability of the methods was tested on biological samples, and metabolite concentrations were found to be in agreement with available data. The method allows the analysis of up to 96 samples per day and was demonstrated to be stable for up to three weeks from acquisition.

Stabilization of Plasma Glucose: The Use of Newer Technology and Pragmatic Laboratory Practice

BACKGROUND

The target values for plasma glucose concentrations for the investigation and diagnosis of diabetes and impaired fasting glucose, and the realization that small incremental changes in glucose concentration increase the risk of adverse events, has led to greater focus on laboratory glucose results. Although analytical methods show acceptable precision, the control of preanalytical error due to the stability of glucose remains problematic. The aim of this study was to compare glucose concentrations in 3 different and commercially available blood tubes, with analysis and storage under current practices and conditions.

METHODS

Blood samples for glucose were obtained from consenting patients attending the Diabetic Clinic at the Royal Victoria Hospital, Belfast. Blood was collected into BD Vacutainer^® Barricor™ Lithium Heparin tubes, BD Vacutainer Fluoride EDTA tubes, and Greiner Vacuette^® FC-Mix (sodium fluoride/citrate/Na₂EDTA) tubes in that order. The Barricor tubes were immediately centrifuged at 4000g for 3 min. All samples were then sent to the Biochemistry Laboratory for analysis on the same day, and again the following day after storage at 4 °C.

RESULTS

There was no significant difference in mean glucose concentrations between immediately centrifuged Barricor and FC-Mix tubes when analyzed on day 0. Both tube types demonstrated higher mean glucose concentrations than traditional fluoride EDTA (F/EDTA) samples.

CONCLUSIONS

Both immediately separated Barricor and citrated FC-Mix plasma preserve glucose concentrations to the same extent, and better than F/EDTA preservative. These newer technologies involved offer pragmatic solutions to improved glucose analysis, allowing laboratories to choose the best option given the source of their samples.