scholarly journals Quantitative Detection of Plasmodium falciparum Using, LUNA-FL, A Fluorescent Cell Counter

2020 ◽  
Vol 8 (9) ◽  
pp. 1356 ◽  
Author(s):  
Muneaki Hashimoto ◽  
Kazumichi Yokota ◽  
Kazuaki Kajimoto ◽  
Musashi Matsumoto ◽  
Atsuro Tatsumi ◽  
...  
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Regression Line ◽  
Malaria Diagnosis ◽  
Quantitative Detection ◽  
Fluorescent Cell ◽  
Blood Samples ◽  
Parasite Detection ◽  
Whole Blood Samples ◽  
Cell Counter

The microscopic examination of Giemsa-stained thin and/or thick blood films (Giemsa microscopy) is the standard method of malaria diagnosis. However, the results of the diagnosis significantly depend on the skills of clinical technicians. Furthermore, sample preparation and analysis are laborious and time-consuming. Therefore, in this study, we investigated if a commercially available fluorescent cell counter, LUNA-FL, was useful for the detection of Plasmodium parasite and the estimation of parasitemia. Whole blood samples from uninfected persons, spiked with P. falciparum-infected erythrocytes, were analysed. Most of the leucocytes and platelets were removed from whole blood samples with SiO2-nanofiber filters set on spin columns. The filtered samples were stained with acridine orange, and automatic detection, as well as counting of erythrocytes and parasites, were performed using LUNA-FL. Whole blood, with various levels of parasites, was analysed by Giemsa microscopy or with LUNA-FL to estimate parasitemia, and a comparative analysis was performed. The coefficient determination value of the regression line was high (R2 = 0.98), indicating that accurate quantitative parasite detection could be performed using LUNA-FL. LUNA-FL has a low running cost; it is compact, fast, and easy to operate, and may therefore be useful for point-of-care testing in the endemic areas.

scholarly journals Whole blood as an alternative to peripheral blood mononuclear cell for detection of total HIV-1 DNA

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ling Lin ◽  
Yong-Song Yue ◽  
Ni-Dan Wang ◽  
Lei-Yan Wei ◽  
Yang Han ◽  
...  
Keyword(s):  
Peripheral Blood Mononuclear Cell ◽  
Mononuclear Cell ◽  
Whole Blood ◽  
Peripheral Blood ◽  
Antiviral Treatment ◽  
Quantitative Detection ◽  
Peripheral Blood Mononuclear ◽  
Blood Samples ◽  
Whole Blood Samples ◽  
Hiv 1

Abstract Background A more time saving, convenient, reproducible, and scalable method is needed to assess total HIV-1 DNA levels. Methods Frozen whole blood and peripheral blood mononuclear cell (PBMC) samples both 200 μl at the same point were used to detect total HIV-1 DNA. Automatic extraction of total HIV-1 DNA was used to ensure the consistency of sample extraction efficiency. The detection reagent was HIV-1 DNA quantitative detection kit and real-time quantitative PCR was utilized. Results Of the 44 included patients, 42 were male and 2 were female, with a median age of 33 years. Thirty-three cases were collected after receiving antiviral treatment, with a median duration of treatment of 3 months, and the other 11 cases were collected before antiviral treatment. The median viral load was 1.83 log10 copies/mL, the median CD4 and CD8 count were 94 and 680 cells/μL, and the median CD4/CD8 ratio was 0.18. The results of the two samples were 3.02 ± 0.39 log10 copies/106 PBMCs in PBMC samples and 3.05 ± 0.40 log10 copies/106 PBMCs in whole blood samples. The detection results of the two methods were highly correlated and consistent by using paired t test (P = 0.370), pearson correlation (r = 0.887, P < 0.0001) and intra-group correlation coefficient (ICC = 0.887, P < 0.0001) and bland-altman [4.55% points were outside the 95% limits of agreement (− 0.340 ~ 0.390)]. Conclusions The results of the whole blood sample test for total HIV-1 DNA are consistent with those of PBMC samples. In a clinical setting it is recommended to use whole blood samples directly for the evaluation of the HIV reservoir.

scholarly journals Longitudinal Evaluation of mRNA Vaccinated Subjects using a Quidel Multianalyte Point-of-Care SARS-CoV-2 IgG Immunoassay

2021 ◽  
Author(s):  
Xi Chen ◽  
Sarika Agarwal ◽  
Stewart Hoelscher ◽  
Richard Egan ◽  
Dipesh Jaiswal ◽  
...  
Keyword(s):  
Immune Response ◽  
Whole Blood ◽  
Point Of Care ◽  
World Population ◽  
Igg Antibody ◽  
Blood Samples ◽  
Whole Blood Samples ◽  
Immuno Assay ◽  
Diseased State ◽  
Prior Infection

Infection from SARS-CoV-2 elicits an immune response to the nucleocapsid (N) and spike proteins (subunits S1 and S2). In this study, we set out to understand the utility of the multiplexed Quidel Sofia 2 SARS-CoV-2 IgG Antibody Fluorescent Immuno-Assay (FIA) that measures IgG antibodies against these three primary SARS-CoV-2 antigens from a single sample in 15 minutes. Using this assay with samples that were collected prior to the COVID-19 pandemic (n=816) and diseased state samples (n=99), the specificities for the three antigens were 98.4-99.9% and 98.0-100.0%, respectively. A longitudinal study was designed to collect weekly fingerstick, venous whole blood, serum and plasma samples from subjects vaccinated with the Moderna or Pfizer/BioNtech mRNA vaccines. The majority of these enrolled subjects had no known prior infection while a subset was known to have had prior COVID-19 infection. We found that the fingerstick whole blood samples performed as effectively as serum, plasma, and venous whole blood samples with a 95.8-99.5% agreement allowing physicians in a near-patient setting to rapidly provide results to their patients. Additionally, as this assay measures an IgG response against three viral proteins, S1, S2 and N, we were able to characterize immune response between i) naturally infected subjects, ii) vaccinated subjects with no prior infection, iii) vaccinated subjects with known prior infection, and iv) vaccinated subjects with prior asymptomatic exposure/infection. The Quidel Sofia 2 SARS-CoV-2 IgG FIA will aid in providing insights to the protective humoral responses as an increasing number of the world population is vaccinated against SARS-CoV-2.

scholarly journals Fingerstick Precision and Total Error of a Point-of-Care HbA1c Test

2019 ◽  
Vol 14 (5) ◽  
pp. 890-895 ◽  
Author(s):  
William D. Arnold ◽  
Kenneth Kupfer ◽  
Monica Hvidsten Swensen ◽  
Kyle S. Fortner ◽  
Harold E. Bays ◽  
...  
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Total Error ◽  
Venous Blood ◽  
Undiagnosed Diabetes ◽  
Components Of Variance ◽  
Blood Samples ◽  
High Hba1c ◽  
Prior Investigation ◽  
Whole Blood Samples

Background: Point-of-care (POC) HbA1c tests hold the promise of reducing the rates of undiagnosed diabetes, provided they exhibit acceptable analytical performance. The precision and total error of the POC (Afinion™ HbA1c Dx) test were investigated using whole blood samples obtained by fingerstick and venipuncture. Methods: Fingerstick samples spanning the assay range were collected from 61 subjects at three representative POC sites. At each site, six fingerstick samples were obtained from each subject and tested on the POC test across two (Afinion AS100) instruments. Repeatability, between-operator, and between-instrument components of variance were calculated using analysis of variance (ANOVA). Four venous samples (low, threshold, medium, and high HbA1c) were measured in duplicate across three instruments using three reagent lots, twice per day over 20-days. Repeatability, between-run, between-day, between-lot, and between-instrument components of variance were calculated. These fingerstick and venous blood results, combined with estimates of imprecision and bias from a prior investigation, allowed for the calculation of the total coefficient of variation (CV) and total error of the POC test using fingerstick and venous whole blood samples. Results: The total imprecision ranged from 1.30% to 2.03% CV using fingerstick samples and from 1.31% to 1.64% CV using venous samples. The total error ranged from 2.87% to 4.75% using fingerstick samples and from 2.93% to 3.80% using venous samples. Conclusions: The POC test evaluated here is precise across its measuring range using both fingerstick and venous whole blood. The calculated total error of the test is well under the accepted quality requirement of ≤6%.

Quality assuring HIV point of care testing using whole blood samples

Pathology ◽  
2016 ◽  
Vol 48 (5) ◽  
pp. 498-500 ◽  
Author(s):  
Raellene Dare-Smith ◽  
Tony Badrick ◽  
Philip Cunningham ◽  
Alison Kesson ◽  
Susan Badman
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Point Of Care Testing ◽  
Blood Samples ◽  
Whole Blood Samples

scholarly journals Accuracy and Precision of a Point-of-Care HbA1c Test

2019 ◽  
Vol 14 (5) ◽  
pp. 883-889
Author(s):  
William D. Arnold ◽  
Kenneth Kupfer ◽  
Randie R. Little ◽  
Meera Amar ◽  
Barry Horowitz ◽  
...  
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Venous Blood ◽  
Reference Laboratory ◽  
Test Results ◽  
Blood Samples ◽  
Accuracy And Precision ◽  
The Mean ◽  
Whole Blood Samples ◽  
Highly Correlated

Background: Point-of-care (POC) hemoglobin A1c (HbA1c) testing has advantages over laboratory testing, but some questions have remained regarding the accuracy and precision of these methods. The accuracy and the precision of the POC Afinion™ HbA1c Dx test were investigated. Methods: Samples spanning the assay range were collected from prospectively enrolled subjects at three clinical sites. The accuracy of the POC test using fingerstick and venous whole blood samples was estimated via correlation and bias with respect to values obtained by an NGSP secondary reference laboratory (SRL). The precision of the POC test using fingerstick samples was estimated from duplicate results by calculating the coefficient of variation (CV) and standard deviation (SD), and separated into its components using analysis of variance (ANOVA). The precision of the POC test using venous blood was evaluated from samples run in four replicates on each of three test cartridge lots, twice per day for 10 consecutive days. The SD and CV by study site and overall were calculated. Results: Across the assay range, POC test results from fingerstick and venous whole blood samples were highly correlated with results from the NGSP SRL ( r = .99). The mean bias was −0.021% HbA1c (−0.346% relative) using fingerstick samples and −0.005% HbA1c (−0.093% relative) using venous samples. Imprecision ranged from 0.62% to 1.93% CV for fingerstick samples and 1.11% to 1.69% CV for venous samples. Conclusions: The results indicate that the POC test evaluated here is accurate and precise using both fingerstick and venous whole blood.

Evaluation of the Xpert HCV Viral Load point-of-care assay from venepuncture-collected and finger-stick capillary whole-blood samples: a cohort study

2017 ◽  
Vol 2 (7) ◽  
pp. 514-520 ◽  
Author(s):  
Jason Grebely ◽  
Francois M J Lamoury ◽  
Behzad Hajarizadeh ◽  
Yasmin Mowat ◽  
Alison D Marshall ◽  
...  
Keyword(s):  
Cohort Study ◽  
Viral Load ◽  
Whole Blood ◽  
Point Of Care ◽  
Blood Samples ◽  
Load Point ◽  
Whole Blood Samples ◽  
Finger Stick ◽  
Point Of Care Assay

scholarly journals Monitoring Thrombin Generation by Electrochemistry: Development of an Amperometric Biosensor Screening Test for Plasma and Whole Blood

2009 ◽  
Vol 55 (3) ◽  
pp. 505-512 ◽  
Author(s):  
Charles Thuerlemann ◽  
André Haeberli ◽  
Lorenzo Alberio
Keyword(s):  
Whole Blood ◽  
Thrombin Generation ◽  
Platelet Rich Plasma ◽  
Point Of Care ◽  
Electrical Signal ◽  
Measuring System ◽  
Screening Tests ◽  
Blood Samples ◽  
Biosensor System ◽  
Whole Blood Samples

Abstract Background: Complete investigation of thrombophilic or hemorrhagic clinical presentations is a time-, apparatus-, and cost-intensive process. Sensitive screening tests for characterizing the overall function of the hemostatic system, or defined parts of it, would be very useful. For this purpose, we are developing an electrochemical biosensor system that allows measurement of thrombin generation in whole blood as well as in plasma. Methods: The measuring system consists of a single-use electrochemical sensor in the shape of a strip and a measuring unit connected to a personal computer, recording the electrical signal. Blood is added to a specific reagent mixture immobilized in dry form on the strip, including a coagulation activator (e.g., tissue factor or silica) and an electrogenic substrate specific to thrombin. Results: Increasing thrombin concentrations gave standard curves with progressively increasing maximal current and decreasing time to reach the peak. Because the measurement was unaffected by color or turbidity, any type of blood sample could be analyzed: platelet-poor plasma, platelet-rich plasma, and whole blood. The test strips with the predried reagents were stable when stored for several months before testing. Analysis of the combined results obtained with different activators allowed discrimination between defects of the extrinsic, intrinsic, and common coagulation pathways. Activated protein C (APC) predried on the strips allowed identification of APC-resistance in plasma and whole blood samples. Conclusions: The biosensor system provides a new method for assessing thrombin generation in plasma or whole blood samples as small as 10 μL. The assay is easy to use, thus allowing it to be performed in a point-of-care setting.

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