scholarly journals The dried blood spot sampling method in the laboratory medicine

2019 ◽  
Vol 120 (03) ◽  
pp. 223-234
Author(s):  
L. Andrlova ◽  
R. Kandar
2013 ◽  
Vol 57 (10) ◽  
pp. 4999-5004 ◽  
Author(s):  
Kim C. M. van der Elst ◽  
Lambert F. R. Span ◽  
Kai van Hateren ◽  
Karin M. Vermeulen ◽  
Tjip S. van der Werf ◽  
...  

ABSTRACTInvasive aspergillosis and candidemia are important causes of morbidity and mortality in immunocompromised and critically ill patients. The triazoles voriconazole, fluconazole, and posaconazole are widely used for the treatment and prophylaxis of these fungal infections. Due to the variability of the pharmacokinetics of the triazoles among and within individual patients, therapeutic drug monitoring is important for optimizing the efficacy and safety of antifungal treatment. A dried blood spot (DBS) analysis was developed and was clinically validated for voriconazole, fluconazole, and posaconazole in 28 patients. Furthermore, a questionnaire was administered to evaluate the patients' opinions of the sampling method. The DBS analytical method showed linearity over the concentration range measured for all triazoles. Results for accuracy and precision were within accepted ranges; samples were stable at room temperature for at least 12 days; and different hematocrit values and blood spot volumes had no significant influence. The ratio of the drug concentration in DBS samples to that in plasma was 1.0 for voriconazole and fluconazole and 0.9 for posaconazole. Sixty percent of the patients preferred DBS analysis as a sampling method; 15% preferred venous blood sampling; and 25% had no preferred method. There was significantly less perception of pain with the DBS sampling method (P= 0.021). In conclusion, DBS analysis is a reliable alternative to venous blood sampling and can be used for therapeutic drug monitoring of voriconazole, fluconazole, and posaconazole. Patients were satisfied with DBS sampling and had less pain than with venous sampling. Most patients preferred DBS sampling to venous blood sampling.


Author(s):  
Gabriella L. Morley ◽  
Stephen Taylor ◽  
Sian Jossi ◽  
Marisol Perez-Toledo ◽  
Sian E. Faustini ◽  
...  

AbstractImportancePopulation-wide serological testing is an essential component in understanding the COVID-19 pandemic. The logistical challenges of undertaking widespread serological testing could be eased through use of a reliable dried blood spot (DBS) sampling method.ObjectiveTo validate the use of dried blood spot sampling for the detection of SARS-CoV-2-specific antibodies.Design, setting and participantsEighty-seven matched DBS and serum samples were obtained from eighty individuals, including thirty-one who were previously PCR-positive for SARS-CoV-2. DBS eluates and sera were used in an ELISA to detect antibodies to the viral spike protein.ResultsSpecific anti-SARS-Cov-2 spike glycoprotein antibodies were detectable in both serum and DBS eluate and there was a significant correlation between the antibody levels detected in matched samples (r = 0.96, p<0.0001). Using serum as the gold standard in the assay, matched DBS samples achieved a Cohen’s kappa coefficient of 0.975 (near-perfect agreement), a sensitivity of 98.1% and specificity of 100%, for detecting anti-spike glycoprotein antibodies.Conclusions and relevanceEluates from DBS samples are a reliable and reproducible source of antibodies to be used for the detection of SARS-CoV-2-specific antibodies. The use of DBS sampling could complement the use of venepuncture in the immunosurveillance of COVID-19 in both low and high income settings.


2021 ◽  
Vol 15 (Supplement_1) ◽  
pp. S338-S339
Author(s):  
N Van den Berghe ◽  
B Verstockt ◽  
V Ballet ◽  
A Gils ◽  
J Sabino ◽  
...  

Abstract Background Various studies have shown an association between ustekinumab serum concentrations and treatment response in patients with Crohn’s disease (CD). However, the time point at which this concentration is most informative for long-term outcome is unknown. Dried blood spot (DBS) sampling allows remote collection of blood for measurements at various time points. By use of this sampling method, the current study aimed to evaluate the exposure-response relationship of ustekinumab throughout the first 24 weeks of treatment and to investigate the time points at which ustekinumab levels could identify patients achieving endoscopic remission. Methods This interim-analysis included DBS (n = 332) and serum (n = 60) samples collected from 13 ustekinumab-treated CD patients at 25 time points during the first 6 months of therapy. All patients received an intravenous infusion of ~6 mg/kg ustekinumab followed by subcutaneous dosing of 90 mg every 8 weeks. Ustekinumab concentrations were measured in serum and DBS extracts using an ustekinumab ELISA (apDia, Turnhout, Belgium). Endoscopic remission was defined as simple endoscopic score for CD (SES-CD) ≤3 after 6 months of therapy. The Mann-Whitney U-test was used to compare unpaired data. Results Three out of 13 patients (23.1%) achieved endoscopic remission. Ustekinumab concentrations in serum correlated with those in DBS extracts (Spearman r = 0.97, p &lt;0.0001). Measurement of the ustekinumab concentration in 38 simultaneously collected DBS and serum samples showed an average DBS-to-serum conversion factor of 2.5±0.7 (mean±SD) with an acceptable interpatient variability (CV ≤29%). Concentration-time profiles showed that patients in remission have a higher area under the curve (AUC), hence a higher drug exposure, than patients not achieving remission (906 vs 466 μg*day/mL, p=0.007, Figure). A negative correlation was observed between the AUC and SES-CD at week 24 (Spearman r = -0.74, p=0.0048). Ustekinumab concentrations in DBS extracts at the intermediate time points week 6, week 11 and week 12 after treatment start exhibited the most significant difference between remitters and non-remitters (Table). In contrast, no significant difference was observed in ustekinumab levels in DBS extracts at week 8, week 16 and week 24 between remitters and non-remitters. Conclusion Intensive DBS sampling showed that ustekinumab-treated CD patients in endoscopic remission have a higher drug exposure throughout the first 24 weeks of treatment than patients not in remission. DBS is an easy sampling method that allows accurate monitoring of ustekinumab exposure over time and could help to identify underexposed patients which might benefit from treatment optimization.


2020 ◽  
Vol 14 (10) ◽  
pp. e0008784
Author(s):  
Laura Doornekamp ◽  
Carmen W. E. Embregts ◽  
Georgina I. Aron ◽  
Simone Goeijenbier ◽  
David A. M. C. van de Vijver ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1532
Author(s):  
Jeffrey Yim ◽  
Olivia Yau ◽  
Darwin F. Yeung ◽  
Teresa S. M. Tsang

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations in the galactosidase A (GLA) gene that result in deficient galactosidase A enzyme and subsequent accumulation of glycosphingolipids throughout the body. The result is a multi-system disorder characterized by cutaneous, corneal, cardiac, renal, and neurological manifestations. Increased left ventricular wall thickness represents the predominant cardiac manifestation of FD. As the disease progresses, patients may develop arrhythmias, advanced conduction abnormalities, and heart failure. Cardiac biomarkers, point-of-care dried blood spot testing, and advanced imaging modalities including echocardiography with strain imaging and magnetic resonance imaging (MRI) with T1 mapping now allow us to detect Fabry cardiomyopathy much more effectively than in the past. While enzyme replacement therapy (ERT) has been the mainstay of treatment, several promising therapies are now in development, making early diagnosis of FD even more crucial. Ongoing initiatives involving artificial intelligence (AI)-empowered interpretation of echocardiographic images, point-of-care dried blood spot testing in the echocardiography laboratory, and widespread dissemination of point-of-care ultrasound devices to community practices to promote screening may lead to more timely diagnosis of FD. Fabry disease should no longer be considered a rare, untreatable disease, but one that can be effectively identified and treated at an early stage before the development of irreversible end-organ damage.


2021 ◽  
Vol 136 ◽  
pp. 104739
Author(s):  
Ranya Mulchandani ◽  
Ben Brown ◽  
Tim Brooks ◽  
Amanda Semper ◽  
Nicholas Machin ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amelia E. Sancilio ◽  
Richard T. D’Aquila ◽  
Elizabeth M. McNally ◽  
Matthew P. Velez ◽  
Michael G. Ison ◽  
...  

AbstractThe spike protein of SARS-CoV-2 engages the human angiotensin-converting enzyme 2 (ACE2) receptor to enter host cells, and neutralizing antibodies are effective at blocking this interaction to prevent infection. Widespread application of this important marker of protective immunity is limited by logistical and technical challenges associated with live virus methods and venous blood collection. To address this gap, we validated an immunoassay-based method for quantifying neutralization of the spike-ACE2 interaction in a single drop of capillary whole blood, collected on filter paper as a dried blood spot (DBS) sample. Samples are eluted overnight and incubated in the presence of spike antigen and ACE2 in a 96-well solid phase plate. Competitive immunoassay with electrochemiluminescent label is used to quantify neutralizing activity. The following measures of assay performance were evaluated: dilution series of confirmed positive and negative samples, agreement with results from matched DBS-serum samples, analysis of results from DBS samples with known COVID-19 status, and precision (intra-assay percent coefficient of variation; %CV) and reliability (inter-assay; %CV). Dilution series produced the expected pattern of dose–response. Agreement between results from serum and DBS samples was high, with concordance correlation = 0.991. Analysis of three control samples across the measurement range indicated acceptable levels of precision and reliability. Median % surrogate neutralization was 46.9 for PCR confirmed convalescent COVID-19 samples and 0.1 for negative samples. Large-scale testing is important for quantifying neutralizing antibodies that can provide protection against COVID-19 in order to estimate the level of immunity in the general population. DBS provides a minimally-invasive, low cost alternative to venous blood collection, and this scalable immunoassay-based method for quantifying inhibition of the spike-ACE2 interaction can be used as a surrogate for virus-based assays to expand testing across a wide range of settings and populations.


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