Dried blood spot specimen quality and validation of a new pre-analytical processing method for qualitative HIV-1 PCR, KwaZulu-Natal, South Africa

A Mathematical Algorithm for Dried Blood Spot Quality Assessment and Results concerning Quality from a Newborn Screening Program

BACKGROUND

In addition to newborn screening, dried blood spots (DBSs) are used for a wide variety of analytes for clinical, epidemiological, and research purposes. Guidelines on DBS collection, storage, and transport are available, but it is suggested that each laboratory should establish its own acceptance criteria.

METHODS

An optical scanning device was developed to assess the quality of DBSs received in the newborn screening laboratory from 11 maternity wards between 2013 and 2018. The algorithm was adjusted to agree with the visual examination consensus of experienced laboratory personnel. Once validated, the algorithm was used to categorize DBS specimens as either proper or improper. Improper DBS specimens were further divided based on 4 types of specimen defects.

RESULTS

In total, 27 301 DBSs were analyzed. Compared with an annual DBS rejection rate of about 1%, automated scanning rejected 26.96% of the specimens as having at least one defect. The most common specimen defect was multi-spotting (ragged DBS, 19.13%). Among maternity wards, improper specimen rates varied greatly between 5.70% and 49.92%.

CONCLUSIONS

Improper specimen rates, as well as the dominant type of defect(s), are mainly institution-dependent, with various maternity wards consistently showing specific patterns of both parameters over time. Although validated in agreement with experienced laboratory personnel consensus, automated analysis rejects significantly more specimens. While continuous staff training, specimen quality monitoring, and problem-reporting to maternities is recommended, a thorough quality assessment strategy should also be implemented by every newborn screening laboratory. An important role in this regard may be played by automation in the form of optical scanning devices.

Self-Powered Microfluidics for Point-of-Care Solutions: From Sampling to Detection of Proteins and Nucleic Acids

Self-powered microfluidics presents a revolutionary approach to address the challenges of healthcare in decentralized and point-of-care settings where limited access to resources and infrastructure prevails or rapid clinical decision-making is critical. These microfluidic systems exploit physical and chemical phenomena, such as capillary forces and surface tension, to manipulate tiny volumes of fluids without the need for external power sources, making them cost-effective and highly portable. Recent technological advancements have demonstrated the ability to preprogram complex multistep liquid operations within the microfluidic circuit of these standalone systems, which enabled the integration of sensitive detection and readout principles. This chapter first addresses how the accessibility to in vitro diagnostics can be improved by shifting toward decentralized approaches like remote microsampling and point-of-care testing. Next, the crucial role of self-powered microfluidic technologies to enable this patient-centric healthcare transition is emphasized using various state-of-the-art examples, with a primary focus on applications related to biofluid collection and the detection of either proteins or nucleic acids. This chapter concludes with a summary of the main findings and our vision of the future perspectives in the field of self-powered microfluidic technologies and their use for in vitro diagnostics applications.

A dried blood spot test for diagnosis of autoimmune pulmonary alveolar proteinosis

Granulocyte/macrophage colony-stimulating factor autoantibodies (GMAbs) mediate the pathogenesis of autoimmune pulmonary alveolar proteinosis (autoimmune PAP) and their quantification in serum by enzyme-linked immunosorbent assay (ELISA) - the serum GMAb test - is the 'gold standard' for diagnosis of autoimmune PAP. Because GMAbs are high in autoimmune PAP and low or undetectable in healthy people, we hypothesized that the ELISA could be adapted for evaluation of blood obtained from the fingertip using a dried blood spot card (DBSC) for specimen collection. Here, we report development of such a method - the DBSC GMAb test - and evaluate its ability to measure GMAb concentration in blood and to diagnose autoimmune PAP. Fresh, heparinized whole blood was obtained from 60 autoimmune PAP patients and 19 healthy people and used to measure the GMAb concentration in blood (by the DBSC GMAb test). After optimization, the DBSC GMAb test was evaluated for accuracy, precision, reliability, sensitivity, specificity, and ruggedness. The coefficient of variation among repeated measurements was low with regard to well-to-well, plate-to-plate, day-to-day, and inter-operator variation, and results were unaffected by exposure of prepared DBSC specimens to a wide range of temperatures (from -80 °C to 65 °C), repeated freeze-thaw cycles, or storage for up to 2.5 months before testing. The limit of blank (LoB), limit of detection (LoD), and lower limit of quantification (LLoQ), were 0.01, 0.21, and 3.5 μg/ml of GMAb in the blood, respectively. Receiver operating curve characteristic analysis identified 2.7 μg/ml as the optimal GMAb concentration cutoff value to distinguish autoimmune PAP from healthy people. This cutoff value was less than the LLoQ and the ranges of GMAb results for autoimmune PAP patients and healthy people were widely separated (median (interquartile range): 22.6 (13.3-43.8) and 0.23 (0.20-0.30) μg/ml, respectively). Consequently, the LLoQ is recommended as the lower limit of the range indicating a positive test result (i.e., that autoimmune PAP is present); lower values indicate a negative test result (i.e., autoimmune PAP is not present). Among the 30 autoimmune PAP patients and 19 healthy people evaluated, the sensitivity and specificity of the DBSC GMAb test were both 100% for a diagnosis of autoimmune PAP. Results demonstrate the DBSC GMAb test reliably measures GMAbs in blood and performs well in the diagnosis of autoimmune PAP.

Reducing sample rejection in Durban, South Africa

Objectives

Rejections of clinical chemistry specimens delays the availability of results, which may impact patient management. The study aims to measure sample rejection rate, identify reasons for sample rejection, evaluate the effect of a campaign to reduce rejection rates and discover which clinical units produced the most insufficient specimen.

Methods

The study measured specimen rejection rates and the contributions of different rejection reasons in calendar 2016 and April 2018-March 2019. The study undertook a 7-intervention campaign to reduce specimen rejection during the 2018-2019 intervention period. It compared rejections rates, number of months with rejection rates ≤1.2%, and distribution of rejection reasons between the two year-long intervals. The study also determined the origin for specimens rejected for the most common rejection reason during one month in the second period.

Results

The overall rejection rate fell significantly from 1.4% in pre-intervention period to 1.2% in the intervention period. The number of months with rejection rates within the target range increased significantly from 2 in the post-intervention period to 6 in the intervention period. Insufficient, hemolysed, and 'too-old' specimen decreased significantly, however, insufficient specimen remained the most frequent rejection reason. In February 2019, one-third of all insufficient specimen came from neonatal units and 24% from the pediatric units.

Conclusions

Interventions decreased significantly both overall and monthly rejection rates above target levels. Insufficient, hemolysed, 'too-old' specimen, became significantly less frequent, however, insufficient specimen remained the most frequent rejection reason. Over a month, most insufficient specimen came from neonatal and pediatric sites.

Remote videolink observation of model home sampling and home testing devices to simplify usability studies for point-of-care diagnostics

Both home sample collection and home testing using rapid point-of-care diagnostic devices can offer benefits over attending a clinic/hospital to be tested by a healthcare professional. Usability is critical to ensure that in-home sampling or testing by untrained users does not compromise analytical performance. Usability studies can be laborious and rely on participants attending a research location or a researcher visiting homes; neither has been appropriate during COVID-19 outbreak control restrictions. We therefore developed a remote research usability methodology using videolink observation of home users. This avoids infection risks from home visits and ensures the participant follows the test protocol in their home environment. In this feasibility study, volunteers were provided with models of home blood testing and home blood sampling kits including a model lancet, sampling devices for dried blood spot collection, and model lateral flow device. After refining the study protocol through an initial pilot (n = 7), we compared instructions provided either as written instructions (n = 5), vs addition of video instructions (n = 5), vs written and video instructions plus videolink supervision by the researcher (n = 5). All users were observed via video call to define which test elements could be assessed remotely. All 22 participants in the study accessed the video call and configured their videolink allowing the researcher to clearly observe all testing tasks. The video call allowed the researcher to assess distinct errors during use including quantitative (volume of blood) and qualitative (inaccurate interpretation of results) errors many of which could compromise test accuracy. All participants completed the tasks and returned images of their completed tests (22/22) and most returned completed questionnaires (20/22). We suggest this remote observation via videolink methodology is a simple, rapid and powerful methodology to assess and optimise usability of point-of-care testing methods in the home setting.

Blood volume and pain perception during finger prick capillary blood sampling: are all safety lancets equal?

OBJECTIVES

This study aimed to assess various types of safety lancets in terms of blood volume and pain perception during capillary blood sampling, a routine finger-puncture procedure for obtaining a small amount of human blood for running various screening and diagnostic tests.

METHODS

Data were collected from 100 adult healthy volunteers following finger-puncture procedure. Four different types of safety lancets were tested (Acti-Lance, Prolance, Medlance Plus, and MediSafe Solo). Each type has its own versions, giving 16 different safety lancets in total.

RESULTS

A significant difference in the mean capillary blood volume was found between blade and needle equipped safety lancets. MediSafe Solo type lancet had no blade version, and hence its use was associated with the lowest mean collected capillary blood volume (42.4 μL). Acti-Lance and Medlance Plus type lancets had one blade version and the mean collected capillary blood volume was 82.2 and 99.0 μL, respectively. Prolance type lancet had two blade versions, and its use was associated with the highest mean capillary blood volume (118.3 μL). The level of pain intensity was evaluated as low by the majority of patients for all lancets. Medlance Plus was the least painful and Acti-Lance was the most painful type of safety lancet. On a 0-to-10 scale of pain, 75% of punctures were assessed by the participants at a level not exceeding 3 points.

CONCLUSIONS

This study suggests that although all investigated safety lancets achieve adequate performance regarding the necessary capillary blood volume to run a diagnostic of test, lancets equipped with blades differ significantly from those equipped with needles in terms of the mean obtained capillary blood volume. Further, although all devices produced relatively low levels of pain, the amount of pain caused by blade versions of safety lancets has been found to be higher than that of needle versions.

CLINICALTRIALS.GOV ID

NCT04001348. (https://clinicaltrials.gov/ct2/show/NCT04001348?term=NCT04001348&draw=2&rank=1).

Correlates and determinants of Early Infant Diagnosis outcomes in North-Central Nigeria

BACKGROUND

A negative status following confirmatory Early Infant Diagnosis (EID) is the desired pediatric outcome of prevention of Mother to Child Transmission (PMTCT) programs. EID impacts epidemic control by confirming non-infected HIV-exposed infants (HEIs) and prompting timely initiation of ART in HIV-infected babies which improves treatment outcomes.

OBJECTIVES

We explored factors associated with EID outcomes among HEI in North-Central Nigeria.

METHOD

This is a cross-sectional study using EID data of PMTCT-enrollees matched with results of HEI's dried blood samples (DBS), processed for DNA-PCR from January 2015 through July 2017. Statistical analyses were done using SPSS version 20.0 to generate frequencies and examine associations, including binomial logistic regression with p < 0.05 being statistically significant.

RESULTS

Of 14,448 HEI in this analysis, 51.8% were female and 95% (n = 12,801) were breastfed. The median age of the infants at sample collection was 8 weeks (IQR 6-20), compared to HEI tested after 20 weeks of age, those tested earlier had significantly greater odds of a negative HIV result (≤ 6 weeks: OR = 3.8; 6-8 weeks: OR = 2.1; 8-20 weeks: OR = 1.5) with evidence of a significant linear trend (p < 0.001). Similarly, HEI whose mothers received combination antiretroviral therapy (cART) before (OR = 11.8) or during the index pregnancy (OR = 8.4) had significantly higher odds as compared to those whose mothers did not receive cART. In addition, HEI not breastfed had greater odds of negative HIV result as compared to those breastfed (OR = 1.9).

CONCLUSIONS

cART prior to and during pregnancy, earlier age of HEI at EID testing and alternative feeding other than breastfeeding were associated with an increased likelihood of being HIV-negative on EID. Therefore, strategies to scale-up PMTCT services are needed to mitigate the burden of HIV among children.

A review of microsampling techniques and their social impact

Conventional skin and blood sampling techniques for disease diagnosis, though effective, are often highly invasive and some even suffer from variations in analysis. With the improvements in molecular detection, the amount of starting sample quantity needed has significantly reduced in some diagnostic procedures, and this has led to an increased interest in microsampling techniques for disease biomarker detection. The miniaturization of sampling platforms driven by microsampling has the potential to shift disease diagnosis and monitoring closer to the point of care. The faster turnaround time for actionable results has improved patient care. The variations in sample quantification and analysis remain a challenge in the microsampling field. The future of microsampling looks promising. Emerging techniques are being clinically tested and monitored by regulatory bodies. This process is leading to safer and more reliable diagnostic platforms. This review discusses the advantages and disadvantages of current skin and blood microsampling techniques.

Common causes of EID sample rejection in Zimbabwe and how to mitigate them

Early infant diagnosis (EID) of HIV provides an opportunity for early HIV detection and access to appropriate Antiretroviral treatment (ART). Dried Blood Spot (DBS) samples are used for EID of exposed infants, born to HIV-positive mothers. However, DBS rejection rates in Zimbabwe have been exceeding the target of less than 2% per month set by the National Microbiology Reference Laboratory (NMRL), in Harare. The aim of this study was to determine the DBS sample rejection rate, the reasons for rejection and the possible associations between rejection and level of health facility where the samples were collected. This is an analytical cross-sectional study using routine DBS sample data from the NMRL in Harare, Zimbabwe, between January and December 2017.A total of 34 950 DBS samples were received at the NMRL. Of these, 1291(4%) were rejected. Reasons for rejection were insufficient specimen volume (72%), missing request form (11%), missing sample (6%), cross-contamination (6%), mismatch of information (4%) and clotted sample (1%). Samples collected from clinics/rural health facilities were five times more likely to be rejected compared to those from a central hospital. Rejection rates were above the set target of <2%. The reasons for rejection were ‘pre-analytical’ errors including labelling errors, missing or inconsistent data, and insufficient blood collected. Samples collected at primary healthcare facilities had higher rejection rates.

Clinical Mass Spectrometry in the Bioinformatics Era: A Hitchhiker's Guide

Mass spectrometry (MS) is a sensitive, specific and versatile analytical technique in the clinical laboratory that has recently undergone rapid development. From initial use in metabolic profiling, it has matured into applications including clinical toxicology assays, target hormone and metabolite quantitation, and more recently, rapid microbial identification and antimicrobial resistance detection by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In this mini-review, we first succinctly outline the basics of clinical mass spectrometry. Examples of hard ionization (electron ionization) and soft ionization (electrospray ionization, MALDI) are presented to demonstrate their clinical applications. Next, a conceptual discourse on mass selection and determination is presented: quadrupole mass filter, time-of-flight mass spectrometer and the Orbitrap; and MS/MS (tandem-in-space, tandem-in-time and data acquisition), illustrated with clinical examples. Current applications in (1) bacterial and fungal identification, antimicrobial susceptibility testing and phylogenetic classification, (2) general unknown urine toxicology screening and expanded new-born metabolic screening and (3) clinical metabolic profiling by gas chromatography are outlined. Finally, major limitations of MS-based techniques, including the technical challenges of matrix effect and isobaric interference; and novel challenges in the post-genomic era, such as protein molecular variants, are critically discussed from the perspective of service laboratories. Computer technology and structural biology have played important roles in the maturation of this field. MS-based techniques have the potential to replace current analytical techniques, and existing expertise and instrument will undergo rapid evolution. Significant automation and adaptation to regulatory requirements are underway. Mass spectrometry is unleashing its potentials in clinical laboratories.

Dried Blood Spots for Global Health Diagnostics and Surveillance: Opportunities and Challenges

There is increasing interest in using dried blood spot (DBS) cards to extend the reach of global health and disease surveillance programs to hard-to-reach populations. Conceptually, DBS offers a cost-effective solution for multiple use cases by simplifying logistics for collecting, preserving, and transporting blood specimens in settings with minimal infrastructure. This review describes methods to determine both the reliability of DBS-based bioanalysis for a defined use case and the optimal conditions that minimize pre-analytical sources of data variability. Examples by the newborn screening, drug development, and global health communities are provided in this review of published literature. Sources of variability are linked in most cases, emphasizing the importance of field-to-laboratory standard operating procedures that are evidence based and consider both stability and efficiency of recovery for a specified analyte in defining the type of DBS card, accessories, handling procedures, and storage conditions. Also included in this review are reports where DBS was determined to not be feasible because of technology limitations or physiological properties of a targeted analyte.