Evaluation of different platforms for the detection of anti-SARS coronavirus-2 antibodies, Thailand

Abstract Background Antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) help determine previous infection in individuals, regardless of whether they are asymptomatic or symptomatic. The detection of antibodies serves several purposes, including supporting other assays for disease diagnosis, conducting seroepidemiological studies, and evaluating vaccines. Many platforms of immunological methods for anti-SARS-CoV-2 antibody detection and their performance require validation. Methods This study evaluated the test performance of three autoanalyzer-based assays (Architect IgG, Vitros IgG, and Vitros total Ig) and one manual ELISA (Wantai total Ig) against a microneutralization (microNT) assay on the detection of SARS-CoV-2 antibodies. Furthermore, an indirect immunofluorescence assay verified the discordant results between the microNT and commercial assays. The test sensitivity, specificity, positive predictive value, and negative predictive value were determined based on four groups of 1005 serum samples: 102 COVID-19 prepandemic sera, 45 anti-SARS-CoV-2 positive sera, 366 sera of people at risk, and 492 sera of citizens returning from countries with a high prevalence of infection. Results The analyses as a whole showed that the performance of these commercial assays was comparable. Each group was also analysed separately to gain further insight into test performance. The Architect did not detect two positive sera of people at risk (prevalence of infection 0.55%). The other methods correctly identified these two positive sera but yielded varying false-positive results. The group of returning travellers with an infection rate of 28.3% (139 of 492) better differentiated the test performance of individual assays. Conclusions High-throughput Architect and Vitros autoanalyzers appear appropriate for working on large sample sizes in countries that can afford the cost. The Wantai ELISA, while requiring more individual time and technical skill, may provide reliable results at a lower cost. The selection of assays will depend on the laboratory facilities and feasibility.

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Investigation of the rapid immunochromatographic test performance in the diagnosis of syphilis; comparison of four serological methods

LaboratoriumsMedizin ◽

10.1515/labmed-2019-0012 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Huseyin Agah Terzi ◽

Ozlem Aydemir ◽

Engin Karakece ◽

Huseyin Hatipoglu ◽

Mehmet Olmez ◽

...

Keyword(s):

Test Performance ◽

Gold Standard ◽

Treponema Pallidum ◽

Rapid Test ◽

Immunochromatographic Test ◽

Rapid Plasma Reagin ◽

Serum Samples ◽

Hemagglutination Assay ◽

Predictive Values ◽

Sensitivity Specificity

AbstractObjectivesTo test the performance of the newly available rapid test for syphilis, we compared it with Treponema pallidum hemagglutination assay (TPHA). Additionally, we investigated the performance of rapid plasma reagin (RPR) and chemiluminescence microparticle immunoassays (CMIA) at our laboratory using TPHA as a gold standard.MethodsThe serum samples of 595 patients with the pre-diagnosis of syphilis were studied by four serological methods. The sensitivity, specificity, and predictive values of RPR, CMIA, and syphilis rapid test were assessed by utilizing TPHA as a gold standard for the diagnosis of syphilis.ResultsOf the patients, 6.2% (37/595) had positive RPR, 5.5% (33/595) had positive CMIA, 5.5% (33/595) had a positive rapid immunochromatographic method and 5% (30/595) had positive TPHA. When TPHA results were taken as the reference, the sensitivity of the rapid test for syphilis was 100%, the specificity was 99.5%, PPV was 90.9%, and NPV was 100.0%.ConclusionsIt was observed that the rapid test for syphilis used in the study was quite successful, its cost was appropriate, and the test was very fast and easy to apply. At the same time, the agreement between syphilis rapid test and TPHA was found to be excellent.

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A Negative Antinuclear Antibody Does Not Indicate Autoantibody Negativity in Myositis: Role of Anticytoplasmic Antibody as a Screening Test for Antisynthetase Syndrome

The Journal of Rheumatology ◽

10.3899/jrheum.160618 ◽

2016 ◽

Vol 44 (2) ◽

pp. 223-229 ◽

Cited By ~ 25

Author(s):

Rohit Aggarwal ◽

Namrata Dhillon ◽

Noreen Fertig ◽

Diane Koontz ◽

Zengbiao Qi ◽

...

Keyword(s):

Lupus Erythematosus ◽

Predictive Value ◽

Antinuclear Antibody ◽

High Sensitivity ◽

Epithelial Cell Line ◽

Antisynthetase Syndrome ◽

Control Groups ◽

Serum Samples ◽

Cytoplasmic Staining ◽

Sensitivity Specificity

Objective.To evaluate the utility of anticytoplasmic autoantibody (anti-CytAb) in antisynthetase antibody–positive (anti-SynAb+) patients.Methods.Anti-SynAb+ patients were evaluated for antinuclear antibody (ANA) and anti-CytAb [cytoplasmic staining on indirect immunofluorescence (IIF)] positivity. Anti-SynAb+ patients included those possessing anti-Jo1 and other antisynthetase autoantibodies. Control groups included scleroderma, systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis, and healthy subjects. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy of anti-CytAb, and ANA were assessed. Anti-CytAb and ANA testing was done by IIF on human epithelial cell line 2, both reported on each serum sample without knowledge of the clinical diagnosis or final anti-SynAb results.Results.Anti-SynAb+ patients (n = 202; Jo1, n = 122; non-Jo1, n = 80) between 1985–2013 with available serum samples were assessed. Anti-CytAb showed high sensitivity (72%), specificity (89%), NPV (95%), and accuracy (86%), but only modest PPV (54%) for anti-SynAb positivity. In contrast, ANA showed only modest sensitivity (50%) and poor specificity (6%), PPV (9%), NPV (41%), and accuracy (12%). Positive anti-CytAb was significantly greater in the anti-SynAb+ patients than ANA positivity (72% vs 50%, p < 0.001), and 81/99 (82%) ANA-negative patients in the anti-SynAb+ cohort had positive anti-CytAb. In contrast, the control groups showed high rates for ANA positivity (93.5%), but very low rates for anti-CytAb positivity (11.5%). Combining anti-CytAb or Jo1 positivity showed high sensitivity (92%) and specificity (89%) for identification of anti-SynAb+ patients.Conclusion.Assessing patients for anti-CytAb serves as an excellent screen for anti-SynAb+ patients using simple IIF. Cytoplasmic staining should be assessed and reported for patients suspected of having antisynthetase syndrome and a negative ANA should not be used to exclude this diagnosis.

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Therapeutic drug monitoring of adalimumab in RA: no predictive value of adalimumab serum levels and anti-adalimumab antibodies for prediction of response to the next bDMARD

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-216996 ◽

2020 ◽

Vol 79 (7) ◽

pp. 867-873

Author(s):

Evy Ulijn ◽

Nathan den Broeder ◽

Maike Wientjes ◽

Noortje van Herwaarden ◽

Inger Meek ◽

...

Keyword(s):

Predictive Value ◽

Evidence Synthesis ◽

Serum Levels ◽

Subsequent Treatment ◽

Therapeutic Drug ◽

Test Accuracy ◽

Serum Samples ◽

Best Evidence Synthesis ◽

Adalimumab Treatment ◽

Sensitivity Specificity

BackgroundAfter adalimumab treatment failure, tumour necrosis factor inhibition (TNFi) and non-TNFi biological disease-modifying anti-rheumatic drugs (bDMARDs) are equally viable options on a group level as subsequent treatment in rheumatoid arthritis (RA) based on the current best evidence synthesis. However, preliminary data suggest that anti-adalimumab antibodies (anti-drug antibodies, ADA) and adalimumab serum levels (ADL) during treatment predict response to a TNFi as subsequent treatment.ObjectiveTo validate the association of presence of ADA and/or low ADL with response to a subsequent TNFi bDMARD or non-TNFi bDMARD. Sub-analyses were performed for primary and secondary non-responders.MethodsA diagnostic test accuracy retrospective cohort study was done in consenting RA patients who discontinued adalimumab after >3 months of treatment due to inefficacy and started another bDMARD. Inclusion criteria included the availability of (random timed) serum samples between ≥8 weeks after start and ≤2 weeks after discontinuation of adalimumab, and clinical outcome measurements Disease Activity Score in 28 joints - C-reactive protein (DAS28-CRP) between 3 to 6 months after treatment switch. Test characteristics for EULAR (European League Against Rheumatism) good response (DAS28-CRP based) after treatment with the next (non-)TNFi bDMARD were assessed using area under the receiver operating characteristic and sensitivity/specificity.Results137 patients were included. ADA presence was not predictive for response in switchers to a TNFi (sensitivity/specificity 18%/75%) or a non-TNFi (sensitivity/specificity 33%/70%). The same was true for ADL levels in patients that switched to a TNFi (sensitivity/specificity 50%/52%) and patients that switched to a non-TNFi (sensitivity/specificity 32%/69%). Predictive value of ADA and ADL were similar for both primary and secondary non-responders to adalimumab.ConclusionsIn contrast to earlier research, we could not find predictive value for response to a second TNFi or non-TNFi for either ADA or random timed ADL.

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An evaluation of the performance of OraQuick® ADVANCE Rapid HIV-1/2 Test in a high-risk population attending genitourinary medicine clinics in East London, UK

International Journal of STD & AIDS ◽

10.1258/ijsa.2008.008132 ◽

2008 ◽

Vol 19 (10) ◽

pp. 665-667 ◽

Cited By ~ 17

Author(s):

J Zelin ◽

N Garrett ◽

J Saunders ◽

F Warburton ◽

J Anderson ◽

...

Keyword(s):

High Risk ◽

Test Performance ◽

Predictive Value ◽

Risk Groups ◽

Antibody Detection ◽

High Risk Population ◽

Antibody Testing ◽

Observer Error ◽

The Uk ◽

Hiv 1

To date, no data have been published on the use of OraQuick® ADVANCE Rapid HIV-1/2 Test (OraQuick) in the UK. We report preliminary findings of an ongoing evaluation of OraQuick in UK genitourinary (GU) medicine clinics. A total of 820 samples from patients in high-risk groups for HIV were tested with OraQuick and results were compared with standard HIV antibody testing. HIV prevalence (enzyme immunoassay [EIA]) was 5.73%, sensitivity of OraQuick was 93.64% (95% CI 82.46–98.66%), specificity 99.87% (99.28–100%), positive predictive value 97.78% (88.27–99.94%) and negative predictive value 99.61% (98.87–99.92%). This includes three false-negatives considered to be due to observer error and now rectified by further training. This has increased test sensitivity to 100%. Our observed test performance of OraQuick compares well with EIA and with other rapid tests. We believe that simple, non-invasive antibody detection tests such as OraQuick can increase HIV testing and diagnosis in UK GU medicine and community settings.

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Diagnostic Performance of Plasma Gastrin Concentration for the Diagnosis of Type 1 Abomasal Ulcer in Water Buffalo: A Preliminary Case Control Study

10.21203/rs.3.rs-592148/v1 ◽

2021 ◽

Author(s):

Syed Ashaq Hussain ◽

S K Uppal ◽

N K Sood

Keyword(s):

Test Performance ◽

Predictive Value ◽

Histopathological Examination ◽

Clinical Signs ◽

Plasma Gastrin ◽

Roc Curve Analysis ◽

Optimal Value ◽

Sensitivity Specificity ◽

Control Study

Abstract The type 1 abomasal ulcer (AU1) does not have specific clinical signs, and there is a need to identify some early biochemical markers for diagnosis of AU1 in cattle and buffaloes. Plasma gastrin is reported to reflect the gastric mucosa damage but its utility for diagnosis of AU1 in buffaloes has not been evaluated. The objective of this study was to study the test performance of plasma gastrin to distinguish healthy buffaloes and buffaloes with AU1. Twenty-three buffaloes with AU1 and six buffaloes without abomasal ulcer were used. Blood samples were collected from the buffaloes, slaughtered in a buffalo specific slaughter house, for estimation of plasma gastrin. After slaughter abomasa were examined for presence of AU1 and were confirmed by histology. The mean plasma gastrin concentration of ulcer positive buffaloes was significantly (p<0.05) higher than the ulcer negative buffaloes. The ROC curve analysis suggested optimal value of plasma gastrin for diagnosis of AU1 was 106.2 pg/ml. Since the abomasal ulcer negative animals were established to be ulcer negative on histopathological examination we consider the values of gastrin valid for detection of abomasal ulceration in buffaloes. The sensitivity, specificity, positive predictive value and negative predictive value of plasma gastrin to diagnose AU1 in buffalo were 78.3, 100, 100 and 69.9, respectively.

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Comparison of Chemicon SimulFluor Direct Fluorescent Antibody Staining with Cell Culture and Shell Vial Direct Immunoperoxidase Staining for Detection of Herpes Simplex Virus and with Cytospin Direct Immunofluorescence Staining for Detection of Varicella-Zoster Virus

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.8.5.909-912.2001 ◽

2001 ◽

Vol 8 (5) ◽

pp. 909-912 ◽

Cited By ~ 23

Author(s):

Edward L. Chan ◽

Ken Brandt ◽

Greg B. Horsman

Keyword(s):

Cell Culture ◽

Predictive Value ◽

Fluorescent Antibody ◽

Turnaround Time ◽

Immunofluorescence Assay ◽

Direct Immunofluorescence ◽

Shell Vial ◽

Varicella Zoster ◽

Simplex Virus ◽

Sensitivity Specificity

ABSTRACT A new rapid direct immunofluorescence assay, the SimulFluor direct fluorescent-antibody (DFA) assay, which can simultaneously detect herpes simplex virus types 1 and 2 (HSV-1 and -2) and varicella-zoster virus (VZV), was evaluated in comparison with our current standard procedures of (i) shell vial direct immunoperoxidase (shell vial IP) staining and cell culture for detection of HSV and (ii) cytospin DFA staining for VZV detection. A total of 517 vesicular, oral, genital, and skin lesion specimens were tested by all three procedures. For HSV detection, the SimulFluor DFA assay had an overall sensitivity, specificity, positive predictive value, and negative predictive value of 80.0, 98.3, 92.3, and 95.1%, respectively, when compared to culture. Shell vial IP staining had a sensitivity, specificity, positive predictive value, and negative predictive value of 87.6, 100, 100, and 96.9%, respectively, when compared with cell culture. The SimulFluor DFA assay, however, offers same-day, 1.5-hours results versus a 1- to 2-day wait for shell vial IP staining results and a 1- to 6-day wait for culture results for HSV. For VZV detection SimulFluor DFA staining detected 27 positive specimens as compared to 31 by our standard cytospin DFA technique—a correlation of 87.1%. A positive SimulFluor reaction for VZV is indicated by yellow-gold fluorescence compared to the bright apple-green fluorescence observed by cytospin DFA staining. There is no difference in turnaround time between the two assays. The SimulFluor DFA assay is a rapid immunofluorescence assay that can detect 80% of the HSV-positive specimens and 87% of the VZV-positive specimens with a 1.5-h turnaround time.

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Assessment of Oropharyngeal Specimens for Discontinuation of Transmission-Based COVID-19 Precautions

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa382 ◽

2020 ◽

Vol 7 (9) ◽

Author(s):

Joshua A Barocas ◽

Miriam Komaromy ◽

Deeanna Haidar ◽

Tamar F Barlam ◽

Beverley L Orr ◽

...

Keyword(s):

Negative Predictive Value ◽

Retrospective Review ◽

Test Performance ◽

Predictive Value ◽

Reference Standard ◽

Paired Samples ◽

Oropharyngeal Swab ◽

Sensitivity Specificity

Abstract We compared oropharyngeal swab test performance with nasopharyngeal testing for discontinuation of transmission-based COVID-19 precautions. We performed a retrospective review of confirmed COVID-19-positive patients who received paired nasopharyngeal and oropharyngeal SARS-CoV-2 tests for clearance from isolation from May 4, 2020, to May 26, 2020. Using nasopharyngeal swabs as the reference standard, we calculated the sensitivity, specificity, and negative predictive value of oropharyngeal swabs. We also calculated the kappa between the 2 tests. A total of 189 paired samples were collected from 74 patients. Oropharyngeal swab sensitivity was 38%, specificity was 87%, and negative predictive value was 70%. The kappa was 0.25. Our study suggests that oropharyngeal swabs are inferior to nasopharyngeal swabs for test-based clearance from COVID-19 isolation.

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An investigation of new toxicity test method performance in validation studies: 2. comparison of three measures of toxicity test performance

Human & Experimental Toxicology ◽

10.1191/0960327102ht253oa ◽

2002 ◽

Vol 21 (6) ◽

pp. 313-323 ◽

Cited By ~ 7

Author(s):

L H Bruner ◽

G J Carr ◽

J W Harbell ◽

R D Curren

Keyword(s):

Test Performance ◽

Predictive Value ◽

Validation Studies ◽

Toxicity Test ◽

Prediction Interval ◽

Test Method ◽

Data Sets ◽

Method Performance ◽

Quantitative Measurements ◽

Sensitivity Specificity

An area that requires further research is how best to measure test method performance in validation studies and how to set criteria that should be used to judge the adequacy of this performance. The studies reported here were designed to begin an investigation of these questions. Computer simulations were used to generate data sets similar to those that might be obtained from a large validation study. These data were then analysed using three procedures including determination of the 95% prediction interval (PI), calculation of Pearson's correlation coefficient and calculation of the contingent probability statistics (CPS), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The results of this work suggest that of the three approaches examined, quantitative measurements with calculation of the 95% PI provide the most information to allow discrimination between the performance of several different NTMs. The results also suggest that dividing data sets into positive and negative toxicity classifications followed by the calculation of CPS leads to considerable information loss. This loss of information may be so significant that it is not possible in certain circumstances to distinguish between NTMs that are adequate and those that are not.

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Prospective study with rapid and low cost serodiagnostic assay for rickettsial infections in children of Vijayapura district, Northern Karnataka, India

International Journal of Contemporary Pediatrics ◽

10.18203/2349-3291.ijcp20182059 ◽

2018 ◽

Vol 5 (4) ◽

pp. 1244 ◽

Cited By ~ 1

Author(s):

Trimal Kulkarni ◽

Govind Benakatti ◽

Laxman Bidari

Keyword(s):

Prospective Study ◽

Clinical Features ◽

Predictive Value ◽

Low Cost ◽

Immunofluorescence Assay ◽

Enzyme Linked Immunosorbent Assay ◽

Rickettsial Infections ◽

Significant Difference ◽

Diagnostic Difficulties ◽

Sensitivity Specificity

Background: Rickettsial infections do exist in study area posing diagnostic difficulties. The study is aimed to compare performance of serological assays for rapid and low-cost diagnosis for rickettsial infections in northern Karnataka, India.Methods: Prospective study was done on 40 children upto 12 years old, hospitalized during 1-year period with fever and presence of one or more of the clinical features of rickettsial infections. Clinical and biochemical findings and serological assays such as indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay-IgM (ELISA-IgM) and Weil-Felix were used to diagnose the disease. Statistical analysis was used to compare the results. Performance characteristics such as sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated using MedCalc for Windows.Results: All 40 patients met the inclusion criteria (23 males and 17 females). Mortality was 2%. Predominant age group was 1-3 years (57.50%). Fever, rashes and hepatosplenomegaly was in all 40 patients (100%); whereas other clinical features showed mixed results. Biochemical findings: anemia in 90%, thrombocytopenia in 45% and elevated transaminases 57.50% and 55%. The ELI-SA-IgM assay showed a sensitivity of 95.00%, a specificity of 95.24% and 95.12% accuracy. The Weil-Felix assay showed a sensitivity of 77.50%, a specificity of 81.63% and 79.78% accu-racy. ELISA-IgM test showed only 5% (p=0.5555) and Weil-Felix test showed 12.50% (p=0.3816) non-significant difference when both compared with IFA test. Whereas ELISA-IgM showed 17.50% more significant (p=0.0239) when compared with Weil-Felix.Conclusions: ELISA-IgM may serve as rapid and low cost serodiagnostic assay over IFA for rickettsial infections.

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Using the modified male osteoporosis self-assessment tool for Taiwan to predict osteoporosis onset – a sub-study of the Taiwan osteoporosis survey

10.1101/479303 ◽

2018 ◽

Author(s):

Dung-Huan Liu ◽

Tien-Tsai Cheng ◽

Jia-Feng Chen ◽

Shan-Fu Yu ◽

Wen-Chan Chiu ◽

...

Keyword(s):

At Risk ◽

Predictive Value ◽

Risk Index ◽

Univariate Analysis ◽

Body Height ◽

Mineral Density ◽

Item Reduction ◽

Taiwanese Men ◽

Sensitivity Specificity ◽

Dxa Scans

AbstractPurposeTo develop a risk index by item reduction from multiple variable regression, which can identify male Taiwanese patients at risk of developing osteoporosis.MethodsTo develop the model, a risk index was identified by item reduction from multivariate regression analysis. Using receiver operating characteristic (ROC) curve analysis and their sensitivity/specificity, MOSTAi was validated in a separate cohort of Taiwanese men and its performance with compared with the National Osteoporosis Foundation recommendations (NOF 2013).ResultsBetween 2008 and 2011 a total of 4,323 males were enrolled for bone mineral density (BMD) measurements. Univariate analysis identified four major risk factors for osteoporosis, including age, body weight (BW), previous fracture and body height. The ROC analysis showed the area under the curve (AUC) for the model based on the three-variable, two-variable (age and BW), and one-variable models (BW), was 0.701 (p<0.001, 95% confidence interval [CI] 0.658-0.744), 0.700 (p<0.001, 95% CI, 0.656-0.742), and 0.690 (p<0.001, 95% CI, 0.646-0.734), respectively. Using the optimal cutoff value (−2) for the OSTA, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) in the validation cohort were 64.0%, 65.7%, 26.9% and 90.2%, respectively. The ROC curves for predicting osteoporosis by MOSTAi, OSTA and NOF 2013 and the AUC for MOSTAi, OSTA and NOF 2013 was 0.706 (p<0.001, 95% CI: 0.664-0.748) and 0.697(p<0.001, 95% CI: 0.657-0.738), respectively.ConclusionThe results showed that MOSTAi could be a more precise model than OSTA and NOF 2013, for identifying men in Taiwan with osteoporosis who require referrals for DXA scans. It was demonstrated that MOSTAi is a simple tool with fair sensitivity/specificity and PPV, and high NPV. MOSTAi could also be a more accurate model than OSTA for identifying men in Taiwan at risk of osteoporosis. In comparison with NOF 2013, MOSTAi is a more accurate and simpler tool for the referral of Taiwanese men for DXA scans.

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