Venous Whole Blood Research Articles

Development and Clinical Evaluation of a Rapid Point of Care Test for Ebola Virus Infection in Humans.

The genus Ebolavirus contains multiple species of viruses that are highly contagious and lethal, often causing severe hemorrhagic fever. To minimize the global threat from Ebola virus disease (EVD), sustainable, field-appropriate tools are needed to quickly screen and triage symptomatic patients and conduct rapid screening of cadavers to ensure proper handling of human remains. The OraQuick® Ebola Rapid Antigen Test is an in vitro diagnostic single-use immunoassay for the qualitative detection of Ebola virus antigens that detects all known species within the genus Ebolavirus. Here, we report the performance of the OraQuick® Ebola Rapid Antigen Test and provide a comparison of its performance with other rapid diagnostic tests (RDTs) for EVD. OraQuick® Ebola demonstrated clinical sensitivity of 84.0% in archived EVD patient venous whole-blood (WB) samples, 90.9% in Ebola virus-infected monkey fingerstick samples, and 97.1% in EVD patient cadaver buccal swabs, as well as clinical specificity of 98.0-100% in venous WB samples and 99.1-100% in contrived saliva samples. It is the only 510(k)-cleared Ebola rapid test, has analytical sensitivity as good as or better than all RDT comparators for EVD, and can detect the Sudan virus. Our data demonstrate that the OraQuick® Ebola Rapid Antigen Test is a sensitive and specific assay that can be used for rapid detection of EBOV in humans and could support efforts for EVD-specific interventions and control over outbreaks.

Volumetric Microsampling of Capillary Blood Spot vs Whole Blood Sampling for Therapeutic Drug Monitoring of Tacrolimus and Cyclosporin A: Accuracy and Patient Satisfaction.

Immunosuppressant therapeutic drug monitoring (TDM) usually requires outpatient travel to hospitals or phlebotomy sites for venous blood collection; however Mitra® Microsampling Device (MSD) sampling could allow self-collection and shipping of samples to a laboratory for analysis. This study examined the feasibility of using volumetric microsampling by MSD for TDM of tacrolimus (TaC) and cyclosporin A (CsA) in transplant patients, along with their feedback on the process. MSD was used to collect TaC and CsA from venous (VB) or capillary (CB) blood. The MSDs were rehydrated, extracted, and analyzed using on-line solid phase extraction coupled to tandem mass spectrometry (SPE-MS/MS). We report an abbreviated method validation of the MSD including: accuracy, precision, linearity, carry-over, and stability using residual venous whole blood (VB) samples. Subsequent clinical validation compared serially collected MSD + CB against VB (200 µL) from transplant patients. Accuracy comparing VB vs. MSD+VB showed high clinical concordance (TaC = 89% and CsA = 98%). Inter- and intra-precision was ≤11.5 %CV for TaC and CsA. Samples were stable for up to 7 days at room temperature with an average difference of <10%. Clinical validation with MSD+CB correlated well with VB for CsA (slope = 0.95, r2 = 0.88, n = 47) and TaC (slope = 0.98, r2 = 0.82, n = 49). CB vs. VB gave concordance of 94% for CsA and 79% for TaC. A satisfaction survey showed 82% of patients preferred having the capillary collection option. Transplant patients favored having the ability to collect capillary samples at home for TaC/CsA monitoring. Our results demonstrate good concordance between MSD+CB and VB for TaC and CsA TDM, but additional studies are warranted.

Analysis of correlation between clinical phenotypes and genotypes in children with distal renal tubular acidosis

Objective To analyze the correlation between clinical phenotypes and genotypes in 6 children with primary distal renal tubular acidosis (dRTA). Methods The clinical data of 6 children confirmed as dRTA in Wuhan Children′s Hospital, Tongji Medical College, Huazhong University of Science & Technology from November 2017 to August 2019 were collected, and related auxiliary examination was performed to assess their growth and development.The venous whole blood was reserved for Trio whole exome sequencing, and full spectrum genetic disease accurate diagnosis cloud platform was applied to systematic data screening and analysis.The suspected mutations were checked by Sanger sequencing, and then the role of protein was predicted by software. Results Clinical manifestations, signs and auxiliary examination results of the 6 children accorded with the diagnostic criteria of dRTA, and the prominent characteristics was growth retardation.One case had knee valgus, one had osteoporosis, and the auxiliary examination results showed that both of them had alkaline urine, metabolic acidosis, and hypokalemia.Three children had nephrocalcinosis, and 2 children had nephrolithiasis.The parents of the 6 patients were all normal without phenotypes.Mutations in the SLC4A1 gene were identified in 4 patients, including 1 child with a reported homozygous autosomal recessive missense mutation(c.2102G>A, p.G701D), who had dRTA and hemolytic anemia, and 3 children with the reported de novo heterozygous autosomal dominant missense mutation(c.1766G>A, p.R589H, c.1765C>T, p.R589C), whose age at diagnosis was related to abnormal renal imaging.Compound heterozygous autosomal recessive mutations in the ATPV1B1 gene were identified in 1 patient, and they were novel heterozygous missense mutations (1153C>A, p.P385T and c. 806C>T, p.P269L). A novel homozygous autosomal recessive missense mutation was identified in 1 patient in the ATPV0A4 gene(c.1899C>A, p.Y633X, 208). Conclusions Mutations in SLC4A1, ATP6V1B1, ATP6V0A4 genes are identified as the main causes of the primary dRTA, and the phenotypes was related to the mutation features and genotypes.Genetic test should be conducted on patients suspected as dRTA for early molecular diagnosis, thereby improving clinical phenotypic screening and individualized treatment. Key words: Distal renal tubular acidosis; Genetic mutation; SLC4A1 gene; ATP6V1B1 gene; ATP6V0A4 gene

Telomere length analysis from minimally‐invasively collected samples: Methods development and meta‐analysis of the validity of different sampling techniques

Telomeres are the protective caps of chromosomes. They shorten with cell replication, age, and possibly environmental stimuli (eg, infection and stress). Short telomere length (TL) predicts subsequent worse health. Although venous whole blood (VWB) is most commonly used for TL measurement, other, more minimally invasive, sampling techniques are becoming increasingly common due to their field-friendliness, allowing for feasible measurement in low-resource contexts. We conducted statistical validation work for measuring TL in dried blood spots (DBS) and incorporated our results into a meta-analysis evaluating minimally invasive sampling techniques to measure TL. We isolated DNA extracts from DBS using a modified extraction protocol and tested how they endured different shipping conditions and long-term cryostorage. We then included our in-house DBS TL validation statistics (correlation values with VWB TL and age) in a series of meta-analyses of results from 24 other studies that published similar associations for values between TL measured in DBS, saliva, and buccal cells. Our modified DBS extraction technique produced DNA yields that were roughly twice as large as previously recorded. Partially extracted DBS DNA was stable for 7 days at room temperature, and still provided reliable TL measurements, as determined by external validation statistics. In our meta-analysis, DBS TL had the highest external validity, followed by saliva, and then buccal cells-possibly reflecting similarities/differences in cellular composition vs VWB. DBS DNA is the best proxy for VWB from the three minimally-invasively specimen types evaluated and can be used to expand TL research to diverse settings and populations.

The use of dried blood spot sampling for the measurement of HbA1c: a cross-sectional study.

BackgroundThe use of dried blood spot (DBS) sampling is an alternative to traditional venous blood collection, and particularly useful for people living in rural and remote areas, and for those who are infirm, house-bound or time-poor. The objective of this study was to assess whether the measurement of glycated haemoglobin A1c (HbA1c) in DBS samples provided comparative and acceptably precise results.MethodsVenous and capillary blood samples were collected from 115 adult participants. After proper instruction, each participant punctured his/her own finger and collected capillary blood samples on pieces of a proprietary cellulose filter paper. Each filter paper was subsequently placed inside a breathable envelope, stored at room temperature, and processed on the same day (D0), four (D4), seven (D7) and fourteen (D14) days after collection. HbA1c was measured in duplicates/triplicates in whole venous blood (WB), capillary blood (capDBS) and venous blood placed on the matrix paper (venDBS), by turbidimetric inhibition immunoassay. Intra-assay coefficients of variation (CV) were calculated. DBS values were compared to WB results using linear regression, Bland-Altman plots and cross-validation models.ResultsEleven and 56 patients had type 1 and type 2 diabetes mellitus, respectively. Mean HbA1c levels were 6.22 ± 1.11 % for WB samples (n = 115). The median intra-assay CV was lower than 3 % for WB and capDBS on all days. Results from capDBS and venDBS showed high correlation and agreement to WB results, with narrow 95 % limits of agreement (except for results from D14 samples), as observed in Bland-Altman plots. When capDBS values were applied to equations derived from regression analyses, results approached those of WB values. A cross-validation model showed that capDBS results on D0, D4 and D7 were close to the WB results, with prediction intervals that were narrow enough to be clinically acceptable.ConclusionsThe measurement of HbA1c from DBS samples provided results that were comparable to results from WB samples, if measured up to seven days after collection. Intra-assay coefficients of variation were low, results were in agreement with the gold-standard, and prediction intervals were clinically acceptable. The measurement of HbA1c through DBS sampling may be considered in situations where traditional venipuncture is not available.Trial registrationAustralian New Zealand Clinical Trials Registry ID ACTRN12613000769785.

Influence of CYP2C19 and P2Y hotspot mutations on high platelet reactivity in patients with clopidogrel intake

Objective To investigate high platelet reactivity effective and relative strength that induced by the CYP2C19 and P2Y hotspot mutations, and explore the applicable testing methods in clinical settings. Methods A case-control study was conducted.104 patients with coronary heart disease were enrolled who administered antiplatelet agent treatment and a 300 mg loading dose of clopidogrel within 12-24h before a PCI.ADP inhibition rate was tested by TEG and flow cytometry method was used to detect VASP index (PRI) and CD62p.The citrated and heparined venous whole blood collected should be collected within 12-24 h after PCI.Genotyping was carried out by pyrophosphate method for the hotspot mutations of drug metabolism in Chinese population concluded CYP2C19 * 2 (681G> A), CYP2C19 * 3 (636G> A)and the platelet glycoprotein receptor gene concluded P2Y1 (893C> T) and P2Y12 (52G> T).According to the CYP2C19 * 2 sequencing results, patients were grouped into three groups, the wild-type group (*1/*1), the heterozygous group (*1/*2)and the homozygous group(*1/*2).Combined with other three mutation sites, platelet function was analyzed among different groups.One-Way ANOVA was used for analysis of variance between groups of different genotypes, and t test and non-parametric test were selected for statistical analysis between the two groups. Results The PRI of wild-type group (35.75±23.11)% was significantly lower (F=9.170, P 0.05) was existed on CD62p among the wild-type group (9.38±11.16)%, the heterozygous group (9.45±8.91)% and homozygous group (10.87±8.31)%.One P2Y12 (52G> T) mutation was found while no P2Y1 (893C> T) mutation was detected among 37 patients. Conclusion The risk of a low response to clopidogrel was related to the carry of CYP2C19 loss-of-function alleles, and the change can be effectively reflected by VASP analysis.(Chin J Lab Med, 2014,37:198-202) Key words: Coronary disease; Ticlopidine; Aryl hydrocarbon hydroxylases; Receptors, purinergic P2Y12; Platelet count; Microfilament proteins; Phosphoproteins; Cell adhesion molecules

Application of dried blood spot sampling combined with LC-MS/MS for genotyping and phenotyping of CYP450 enzymes in healthy volunteers

An early clinical development study (phase I) was conducted to determine the usefulness of dried blood spot (DBS) sampling as an alternative to venous sampling for phenotyping and genotyping of CYP450 enzymes in healthy volunteers. Midazolam (MDZ) was used as a substrate for phenotyping CYP3A4 activity; the concentrations of MDZ and its main metabolite 1'-hydroxymidazolam (1-OH MDZ) were compared between the DBS method from finger punctures, plasma and whole blood (WB), drawn by venipuncture, whereby several methodological parameters were studied (i.e. punch width, amount of dots analyzed and storage time stability). Genotyping between DBS and venous WB samples was compared for CYP2D6 (*3, *4, *6), CYP2C19 (*2, *3), CYP3A4 (*1B) and CYP3A5 (*3C). In addition, the subject's and phlebotomist's satisfaction with venous blood sampling compared with the DBS method was evaluated using a standardized questionnaire. An LC-MS/MS method for the quantification of the MDZ and 1-OH MDZ concentrations in DBS samples was developed and validated in the range of 0.100-100 ng/mL. No compromises were made for the limits of quantification of the DBS-LC-MS/MS method vs the authentic plasma and WB methods.

Assessment of trueness of glucose measurement instruments with different specimen matrices

Background The trueness of glucose monitors is commonly assessed using whole-blood samples and a clinical analyzer as a comparison method. In this study, the effect of specimen matrix on trueness of one clinical analyzer and one glucose monitor was compared with a gas chromatography–mass spectrometry (GC/MS) reference method, using split-sample comparison with capillary whole blood (CWB), venous whole blood (VWB), and plasma (PL). Methods CWB was analyzed by the glucose monitor and the GC/MS reference method. VWB was analyzed by the glucose monitor, clinical analyzer, and the GC/MS method. PL was analyzed by the clinical analyzer and the GC/MS reference method. Results For the glucose monitor, the bias was 0.4% and − 18.2% for CWB and VWB, respectively. The clinical analyzer had a bias of − 25.4% for VWB and − 12.0% for PL and a proportional bias was detected in both specimens. Using the clinical analyzer as a comparison method, the glucose monitor had a proportional bias of − 9.8%. Conclusion The trueness of clinical analyzers can be affected by the specimen matrix that needs to be assessed before they are used as comparison method to assess trueness of glucose monitors.

Oral glucose tolerance test in healthy pregnant Nigerian women.

Oral glucose tolerance tests (OGTTs) with 75 g glucose were performed in 20 healthy pregnant Nigerian women in each trimester of pregnancy and the puerperium; 34 nonpregnant control subjects matched for age and parity were also studied. The blood glucose levels from fasting to 60 min were lower in pregnant subjects, but the 90- and 120-min values were higher. The highest blood glucose values were observed in the first trimester with an apparent improvement in glucose tolerance in the second and third trimesters. This observation is strikingly different from the established pattern of OGTT in pregnant Caucasian women. With pooled data from OGTT results in the three trimesters for the 20 pregnant women (60 OGTTs), a statistically derived criterion (based on mean + 2SD approximated to the nearest 5) for the interpretation of OGTT in pregnant Nigerian women was devised. This criterion defines the upper limits of normal for venous whole-blood glucose in pregnant Nigerian women during an OGTT with a 75-g glucose load as follows: fasting, 90; 30 min, 135; 60 min, 150; 90 min, 145; and 120 min, 125 mg/dl. These values are lower than those recommended for pregnant women by the National Diabetes Data Group (O'Sullivan and Mahan criteria) and the World Health Organization. The results from this study underscore the need for caution regarding uncritical application of data from one racial or ethnic group to others.