Performance of three automated fourth-generation combined HIV antigen/antibody assays in large-scale screening of blood donors and clinical samples

Antigen detection rapid diagnostic tests have been developed for first-line large-scale screening given their rapidity, simplicity, and accuracy. This study evaluates the diagnostic performance of an antigen detection rapid diagnostic test (BLOK BioScience, London, UK) detecting SARS-CoV-2 nucleocapsid protein. Serially diluted SARS-CoV-2 isolate and 110 NPS from COVID-19 patients were tested to determine the test’s sensitivity, and other viral isolates and 20 NPS from non-infected individuals were, for specificity, also tested. Ten clinical samples from COVID-19 patients with SARS-CoV-2 variants, including alpha, beta, gamma, delta, and eta variants, were collected to evaluate the test’s potential application in detecting emerging variants. Overall sensitivity was 92%, and stratifying into viral loads yielded 100% for Ct < 25 samples including SARS-CoV-2 variants, but 11.11% for Ct ≥ 30 samples. The analytical sensitivity of log10 TCID50/mL 2.0 was identified for SARS-CoV-2. Ninety-seven percent specificity with only SARS-CoV cross-reactivity lead to the Youden index of 0.89. The rapid diagnostic test has a high sensitivity for detecting SARS-CoV-2 in high viral load samples, possibly including emerging SARS-CoV-2 variants, but reduced sensitivity in low viral load samples suggests its optimized usage as a complementary testing method to other tests, including RT-PCR or a point-of-care test for large-scale screening, particularly for pandemic areas or airport border infection control.

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Clinical Application Evaluation of a Fourth-Generation HIV Antigen Antibody Combination Screening Assay

Clinical Laboratory ◽

10.7754/clin.lab.2019.190220 ◽

2019 ◽

Vol 65 (10/2019) ◽

Author(s):

Hui Han ◽

Yanhua Huang ◽

Qian Dong ◽

Yunxiu Huang ◽

Jianqiang Lu ◽

...

Keyword(s):

Clinical Application ◽

Fourth Generation ◽

Screening Assay ◽

Hiv Antigen ◽

Antigen Antibody

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A Protocol for Sensitive Large-Scale Screening of Blood Donors for IgA Deficiency

Vox Sanguinis ◽

10.1111/j.1423-0410.1985.tb00151.x ◽

1985 ◽

Vol 48 (2) ◽

pp. 84-88 ◽

Cited By ~ 14

Author(s):

A.F. Hunt ◽

D.L. Allen ◽

D.L. Aries ◽

J.J. Strange

Keyword(s):

Large Scale ◽

Blood Donors ◽

Iga Deficiency ◽

Large Scale Screening

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Comparison of Detection Limits of Fourth- and Fifth-Generation Combination HIV Antigen-Antibody, p24 Antigen, and Viral Load Assays on Diverse HIV Isolates

Journal of Clinical Microbiology ◽

10.1128/jcm.02045-17 ◽

2018 ◽

Vol 56 (8) ◽

Cited By ~ 16

Author(s):

Mars Stone ◽

John Bainbridge ◽

Ana M. Sanchez ◽

Sheila M. Keating ◽

Andrea Pappas ◽

...

Keyword(s):

Viral Load ◽

Acute Infection ◽

Fourth Generation ◽

Next Generation ◽

Acute Hiv Infection ◽

Viral Loads ◽

Hiv Antigen ◽

Loads Analysis ◽

Acute Hiv ◽

Antigen Antibody

ABSTRACTDetection of acute HIV infection is critical for HIV public health and diagnostics. Clinical fourth-generation antigen (Ag)/antibody (Ab) combination (combo) and p24 Ag immunoassays have enhanced detection of acute infection compared to Ab-alone assays but require ongoing evaluation with currently circulating diverse subtypes. Genetically and geographically diverse HIV clinical isolates were used to assess clinical HIV diagnostic, blood screening, and next-generation assays. Three-hundred-member panels of 20 serially diluted well-characterized antibody-negative HIV isolates for which the researchers were blind to the results (blind panels) were distributed to manufacturers and end-user labs to assess the relative analytic sensitivity of currently approved and preapproved clinical HIV fourth-generation Ag/Ab combo or p24 Ag-alone immunoassays for the detection of diverse subtypes. The limits of detection (LODs) of virus were estimated for different subtypes relative to confirmed viral loads. Analysis of immunoassay sensitivity was benchmarked against confirmed viral load measurements on the blind panel. On the basis of the proportion of positive results on 300 observations, all Ag/Ab combo and standard sensitivity p24 Ag assays performed similarly and within half-log LODs, illustrating the similar breadth of reactivity and diagnostic utility. Ultrasensitive p24 Ag assays achieved dramatically increased sensitivities, while the rapid combo assays performed poorly. The similar performance of the different commercially available fourth-generation assays on diverse subtypes supports their use in broad geographic settings with locally circulating HIV clades and recombinant strains. Next-generation preclinical ultrasensitive p24 Ag assays achieved dramatically improved sensitivity, while rapid fourth-generation assays performed poorly for p24 Ag detection.

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Clinical autoantibody detection by microarray

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2016-0533 ◽

2017 ◽

Vol 55 (4) ◽

Cited By ~ 2

Author(s):

Doreen Dillaerts ◽

Heidi De Baere ◽

Xavier Bossuyt

Keyword(s):

Blood Donors ◽

Simultaneous Detection ◽

Clinical Samples ◽

Systemic Autoimmune Disease ◽

Farr Assay ◽

Nuclear Antigens ◽

Antibody Assays ◽

Low Sensitivity ◽

Autoantibody Detection ◽

Dsdna Antibodies

Abstract Background: AMiDot is a microdot array-based immunoassay that allows simultaneous detection of multiple autoantibodies on a single patient. We evaluated the AMiDot “Systemic Autoimmune Disease” (SAD) panel, which detects antibodies to 17 different antigens. Methods: AMiDot was performed on 184 samples from blood donors and on 280 randomly selected clinical samples containing antibodies to extractable nuclear antigens or to dsDNA. The results obtained by AMiDot on the clinical samples were compared to results obtained by EliA (Thermo Fisher) for anti-Ro60, anti-La, anti-RNP, anti-Scl-70, anti-CENPB, anti-Sm, and anti-Jo-1 and by Farr assay for anti-dsDNA. Discordant results were further analyzed by immunodot (D-tek). Results: Concordance between AMiDot and EliA was ≥87% and κ agreement ≥0.44. When compared to EliA and immunodot (in case of discordance between AMiDot and EliA), concordance improved to ≥91% and κ agreement to ≥0.77. The sensitivity of AMiDot (compared to EliA and immunodot, in case of discordance between AMiDot and EliA) was ≥93%, except for anti-Ro60 (84%). The concordance and κ agreement of AMiDot with the Farr assay (for dsDNA antibodies) was, respectively, 84% and 0.33. The sensitivity of AMiDot for dsDNA (compared to Farr assay) was 25%. The specificity was ≥97% (in blood donors as well as in clinical samples). The within-run imprecision was 9%–27% and the between-run imprecision 29%–39%. Conclusions: AMiDot offers an alternative to line immunodot assay. Individual antibody assays might suffer from low sensitivity.

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