scholarly journals Reference and point-of-care testing for G6PD deficiency: Blood disorder interference, contrived specimens, and fingerstick equivalence and precision

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257560
Author(s):  
Sampa Pal ◽  
Jane Myburgh ◽  
Pooja Bansil ◽  
Amanda Hann ◽  
Lynn Robertson ◽  
...  
Keyword(s):  
Test Performance ◽  
G6pd Deficiency ◽  
Clinical Performance ◽  
Point Of Care ◽  
The United States ◽  
G6pd Activity ◽  
Good Precision ◽  
Point Of Care Testing ◽  
Blood Disorders ◽  
Blood Disorder

Certain clinical indications and treatments such as the use of rasburicase in cancer therapy and 8-aminoquinolines for Plasmodium vivax malaria treatment would benefit from a point-of-care test for glucose-6-phosphate dehydrogenase (G6PD) deficiency. Three studies were conducted to evaluate the performance of one such test: the STANDARD™ G6PD Test (SD BIOSENSOR, South Korea). First, biological interference on the test performance was evaluated in specimens with common blood disorders, including high white blood cell (WBC) counts. Second, the test precision on fingerstick specimens was evaluated against five individuals of each, deficient, intermediate, and normal G6PD activity status. Third, clinical performance of the test was evaluated at three point-of-care settings in the United States. The test performed equivalently to the reference assay in specimens with common blood disorders. High WBC count blood samples resulted in overestimation of G6PD activity in both the reference assay and the STANDARD G6PD Test. The STANDARD G6PD Test showed good precision on multiple fingerstick specimens from the same individual. The same G6PD threshold values (U/g Hb) were applied for a semiquantitative interpretation for fingerstick- and venous-derived results. The sensitivity/specificity values (95% confidence intervals) for the test for G6PD deficiency were 100 (92.3–100.0)/97 (95.2–98.2) and 100 (95.7–100.0)/97.4 (95.7–98.5) for venous and capillary specimens, respectively. The same values for females with intermediate (> 30% to ≤ 70%) G6PD activity were 94.1 (71.3–99.9)/88.2 (83.9–91.7) and 82.4 (56.6–96.2)/87.6(83.3–91.2) for venous and capillary specimens, respectively. The STANDARD G6PD Test enables point-of-care testing for G6PD deficiency.

scholarly journals Clinical Evaluation of BD Veritor SARS-CoV-2 Point-of-Care Test Performance Compared to PCR-Based Testing and versus the Sofia 2 SARS Antigen Point-of-Care Test

2020 ◽  
Vol 59 (1) ◽  
pp. e02338-20 ◽  
Author(s):  
Stephen Young ◽  
Stephanie N. Taylor ◽  
Catherine L. Cammarata ◽  
Katey G. Varnado ◽  
Celine Roger-Dalbert ◽  
...  
Keyword(s):  
Test Performance ◽  
Rapid Detection ◽  
Clinical Performance ◽  
Point Of Care ◽  
Point Of Care Testing ◽  
Pcr Assay ◽  
Point Of Care Test ◽  
Nasal Swabs ◽  
High Degree ◽  
Antigen Testing

ABSTRACTThe clinical performance of the BD Veritor System for Rapid Detection of SARS-CoV-2 nucleocapsid antigen (Veritor), a chromatographic immunoassay used for SARS-CoV-2 point-of-care testing, was evaluated using nasal specimens from individuals with COVID-19 symptoms. Two studies were completed to determine clinical performance. In the first study, nasal specimens and either nasopharyngeal or oropharyngeal specimens from 251 participants with COVID-19 symptoms (≤7 days from symptom onset [DSO], ≥18 years of age) were utilized to compare Veritor with the Lyra SARS-CoV-2 PCR assay (Lyra). In the second study, nasal specimens from 361 participants with COVID-19 symptoms (≤5 DSO, ≥18 years of age) were utilized to compare performance of Veritor to that of the Sofia 2 SARS Antigen FIA test (Sofia 2). The positive, negative, and overall percent agreement (PPA, NPA, and OPA, respectively) were the primary outcomes. In study 1, the PPA for Veritor, compared to Lyra, ranged from 81.8 to 87.5% across the 0 to 1 and 0 to 6 DSO ranges. In study 2, Veritor had PPA, NPA, and OPA values of 97.4, 98.1, and 98.1%, respectively, with Sofia 2. Discordant analysis showed one Lyra positive missed by Veritor and five Lyra positives missed by Sofia 2; one Veritor positive result was negative by Lyra. Veritor met FDA emergency use authorization (EUA) acceptance criteria for SARS-CoV-2 antigen testing for the 0 to 5 and 0 to 6 DSO ranges (PPA values of 83.9% and 82.4%, respectively). Veritor and Sofia 2 showed a high degree of agreement for SARS-CoV-2 detection. The Veritor test allows for more rapid COVID-19 testing utilizing easy-to-collect nasal swabs but demonstrated <100% PPA compared to PCR.

Performance Evaluation and Multicenter Consistency Study of Smartphone-based Hipee S2 Point-of-care Testing Urine Dipstick Analyser: Evaluation Study (Preprint)

2021 ◽  
Author(s):  
Qiang Zhang ◽  
Guoqing Wang ◽  
Xiaolong Zong ◽  
Jinghua Sun
Keyword(s):  
Health Management ◽  
Clinical Performance ◽  
Point Of Care ◽  
Method Comparison ◽  
Evaluation Study ◽  
Analytical Performance ◽  
Point Of Care Testing ◽  
Urine Dipstick ◽  
Quantitative Results ◽  
Carry Over

BACKGROUND With advances in mobile technology, smartphone-based point-of-care testing (POCT) urinalysis hold great potential for disease screening and health management for clinicians and individual users. The POCT devices need to have good analytical and clinical performance, but data are lacking. OBJECTIVE The purpose of this study is to evaluate the analytical performance of smartphone-based Hipee S2 POCT urine dipstick analyser. METHODS A total of 1,603 urine samples from three hospitals were collected. Precision, drift, carry-over, interference, and method comparison of Hipee S2 were evaluated. RESULTS The precision for each parameter, assessed by control materials, was acceptable. No sample carry-over or drift was observed. Ascorbate solution with 1 g/L had an inhibitory effect for the haemoglobin test. Agreement for specific gravity (SG) varied between moderate to substantial, for pondus hydrogenii (pH) was moderate, and for other parameters varied between substantial to excellent, on comparing the results obtained by Hipee S2 with those measured by laboratory reference analysers. The semi-quantitative results of microalbumin and creatinine were highly correlated with the quantitative results. CONCLUSIONS Hipee S2 POCT urine analyser showed acceptable analytical performance as a semi-quantitative method. It serves as a convenient alternate device for clinicians and individual users for urinalysis and health management.

Point-of-Care Testing Error: Sources and Amplifiers, Taxonomy, Prevention Strategies, and Detection Monitors

2005 ◽  
Vol 129 (10) ◽  
pp. 1262-1267 ◽  
Author(s):  
Frederick A. Meier ◽  
Bruce A. Jones
Keyword(s):  
Direct Observation ◽  
Test Performance ◽  
Point Of Care ◽  
Point Of Care Testing ◽  
Patient Identification ◽  
Test Procedures ◽  
Method Performance ◽  
Therapeutic Implications ◽  
Reasonable Approach ◽  
Structured Observation

Abstract Context.—In a survey performed 4 years ago, testing venues doing only point-of-care testing (POCT) made up 78% of sites for patient testing licensed under federal regulations. Objectives.—To identify sources of POCT error, to present a classification of such errors, to suggest strategies to prevent errors, and to describe monitors that assess and reduce the frequency of errors. Design.—To identify sources of POCT error, large studies of error among US Federal Certificate of Waiver laboratories (CoWs) and practitioner-performed microscopy certificate holders were reviewed. To facilitate investigation and management of POCT error, a taxonomy of such errors (modified from a classification previously published by Gerald Kost) was used to identify 4 steps with error potential in each of the 3 phases (ie, preanalytic, analytic, and postanalytic) of the POCT process. To prevent observed POCT errors, 4 strategies are suggested: direct observation of instrument/method functionality, structured observation of method performance, proficiency testing/use of relevant test scenarios, and autonomation. To assess frequency of errors, a quartet of indices are introduced as detection monitors: order documentation, patient identification, specimen adequacy, and result integrity. Results.—Three sources of POCT error were identified: operator incompetence, nonadherence to test procedures, and use of uncontrolled reagents and equipment. Three other characteristics of many point-of-care tests amplify their risk of error: incoherent regulation, rapid availability of results, and the results' immediate therapeutic implications. Two members of the quartet of detection monitors, order documentation and specimen adequacy, are relatively difficult to measure and are controversial, but the other 2, patient identification and result integrity, are easier to assess and are relatively widely accepted. Conclusions.—Point-of-care testing errors are relatively common, their frequency is amplified by incoherent regulation, and their likelihood of affecting patient care is amplified by the rapid availability of POCT results and the results' immediate therapeutic implications. The modified Kost taxonomy offers a reasonable approach to the identification of POCT errors. Direct observation of test functionality, structured observation of test performance, and testing the competence of POCT operators, as well as autonomation of devices, are strategies to prevent such errors. In this context, we suggest monitoring POCT order documentation, patient identification, specimen integrity, and result reporting to detect errors in this sort of testing.

scholarly journals Comparison of a Point-of-Care Assay and a High-Complexity Assay for Detection of SARS-CoV-2 RNA

2020 ◽  
Vol 5 (6) ◽  
pp. 1307-1312 ◽  
Author(s):  
Bryan Stevens ◽  
Catherine A Hogan ◽  
Malaya K Sahoo ◽  
ChunHong Huang ◽  
Natasha Garamani ◽  
...  
Keyword(s):  
Test Performance ◽  
Target Genes ◽  
Point Of Care ◽  
The United States ◽  
Kappa Coefficient ◽  
Nucleic Acid Amplification ◽  
Limited Data ◽  
Percent Agreement ◽  
United States Food ◽  
States Food

Abstract Background Numerous nucleic acid amplification assays utilizing different target genes of the SARS-CoV-2 genome have received emergency use authorization (EUA) by the United States Food and Drug Administration (FDA). Limited data are available comparing the test performance characteristics of these assays. Methods A diagnostic comparison study was performed to evaluate the performance of the Cepheid Xpert Xpress SARS-CoV-2 assay compared to the Hologic Panther Fusion SARS-CoV-2 assay using clinical nasopharyngeal specimens. Agreement between the two assays was assessed by overall, positive, and negative percent agreement and Cohen’s kappa coefficient. Results A total of 104 (54 positive and 50 negative) clinical nasopharyngeal samples were tested by both assays. Using the Panther Fusion as a reference standard, the Xpert demonstrated an overall agreement of 99.0% [95% confidence interval (CI): 94.8–100], positive percent agreement of 98.1% (95% CI: 90.1–100), and a negative percent agreement of 100% (95% CI: 94.2–100). The kappa coefficient was 0.98 (95% CI: 0.94–1.0). One sample positive by the Panther Fusion with a cycle threshold (Ct) of 38.6 was found to be reproducibly negative by the Xpert assay. Conclusions The Cepheid Xpert Xpress SARS-CoV-2 assay provides test performance comparable to the Hologic Panther Fusion SARS-CoV-2 assay while offering laboratories rapid, on-demand testing capacity.

scholarly journals Clinical evaluation of BD Veritor SARS-CoV-2 point-of-care test performance compared to PCR-based testing and versus the Sofia 2 SARS Antigen point-of-care test.

2020 ◽  
Author(s):  
Stephen Young ◽  
Stephanie Taylor ◽  
Catherine Cammarata ◽  
Celine Roger-Dalbert ◽  
Amanda Montano ◽  
...  
Keyword(s):  
Test Performance ◽  
Rapid Detection ◽  
Clinical Performance ◽  
Point Of Care ◽  
Point Estimate ◽  
Pcr Assay ◽  
Point Of Care Test ◽  
Nasal Swabs ◽  
High Degree ◽  
Antigen Testing

Objectives The clinical performance of the BD Veritor System for Rapid Detection of SARS-CoV-2 antigen (Veritor), a chromatographic immunoassay that detects the SARS-CoV-2 nucleocapsid antigen as a point-of-care test, was evaluated on nasal specimens from individuals with COVID-19 symptoms. Methods and Materials Two studies were completed to determine clinical performance. In the first study, nasal specimens and either nasopharyngeal or oropharyngeal specimens from 251 participants with COVID-19 symptoms (<=7 days from symptom onset [DSO]), >=18 years of age, were utilized to compare Veritor with the Lyra SARS-CoV-2 PCR Assay (Lyra). In the second study, nasal specimens from 361 participants with COVID-19 symptoms (<=5 DSO), >=18 years of age, were utilized to compare performance of Veritor to that of the Sofia 2 SARS Antigen FIA test (Sofia 2). Positive, negative, and overall percent agreement (PPA, NPA, and OPA, respectively) were the primary outcomes. Results In study 1, PPA for Veritor, compared to Lyra, ranged from 81.8%-87.5% for 0-1 through 0-6 DSO ranges. In study 2, Veritor had a PPA, NPA, and OPA of 97.4%, 98.1%, and 98.1%, respectively, with Sofia 2. Discordant analysis showed one Lyra positive missed by Veritor and five Lyra positives missed by Sofia 2; one Veritor positive result was negative by Lyra. Conclusions Veritor met FDA-EUA acceptance criteria for SARS-CoV-2 antigen testing (>=80% PPA point estimate) for the 0-5 and 0-6 DSO ranges. Veritor and Sofia 2 showed a high degree of agreement for SARS-CoV-2 detection. The Veritor test should facilitate rapid and reliable results for COVID-19 diagnosis utilizing easy-to-collect nasal swabs.

scholarly journals A novel RT-LAMP workflow for rapid salivary diagnostics of COVID-19 and effects of age, gender and time from symptom onset

2021 ◽  
Author(s):  
Gerson Shigeru Kobayashi ◽  
Luciano Abreu Brito ◽  
Danielle De Paula Moreira ◽  
Angela May Suzuki ◽  
Gabriella Shih Ping Hsia ◽  
...  
Keyword(s):  
Viral Load ◽  
Symptom Onset ◽  
Clinical Performance ◽  
Point Of Care ◽  
Rapid Diagnostics ◽  
Rt Pcr ◽  
Point Of Care Testing ◽  
Viral Loads ◽  
Peak Viral Load ◽  
Salivary Diagnostics

Objectives: Rapid diagnostics is pivotal to curb SARS-CoV-2 transmission, and saliva has emerged as a practical alternative to naso/oropharyngeal (NOP) specimens. We aimed to develop a direct RT-LAMP workflow for viral detection in saliva, and to provide more information regarding its potential in COVID-19 diagnostics. Methods: Clinical and contrived specimens were used to screen/optimize formulations and sample processing protocols. Salivary viral load was determined in symptomatic patients to evaluate clinical performance (n = 90) and to characterize saliva based on age, gender and time from onset of symptoms (n = 49). Results: The devised workflow achieved 93.2% sensitivity, 97% specificity, and 0.895 Kappa for salivas containing >102 copies/μL. Further analyses in saliva showed peak viral load in the first days of symptoms and lower viral loads in females, particularly among young individuals (<38 years). NOP RT-PCR data did not yield relevant associations. Conclusions: This novel saliva RT-LAMP workflow can be applied to point-of-care testing. This work reinforces that saliva better correlates with transmission dynamics than NOP specimens, and reveals gender differences that may reflect higher transmission by males. To maximize detection, testing should be done immediately after symptom onset, especially in females.

scholarly journals Point-of-Care Testing of Blood Glucose: Clinical Performance and Laboratory Efficiency

2019 ◽  
Author(s):  
Wei-Shang Shih ◽  
Pei-Fang Yang ◽  
Tzu-Fei Chi ◽  
Liang Li Huang ◽  
Chang-I Chen ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Clinical Performance ◽  
Point Of Care ◽  
Point Of Care Testing
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