Evaluation of Orthogonal Testing Algorithm for Detection of SARS-CoV-2 IgG Antibodies.
Clin Chem
; 66(12): 1531-1537, 2020 12 01.
Article
in English
| MEDLINE | ID: covidwho-745843
ABSTRACT
BACKGROUND:
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody testing is an important tool in assessment of pandemic progress, contact tracing, and identification of recovered coronavirus disease 2019 (COVID-19) patients. We evaluated an orthogonal testing algorithm (OTA) to improve test specificity in these use cases.METHODS:
A two-step OTA was applied where individuals who initially tested positive were tested with a second test. The first-line test, detecting IgG antibodies to the viral nucleocapsid protein, was validated in 130 samples and the second-line test, detecting IgG antibodies to the viral spike protein in 148 samples. The OTA was evaluated in 4333 clinical patient specimens. The seropositivity rates relative to the SARS-CoV-2 PCR positivity rates were evaluated from our entire patient population data (n = 5102).RESULTS:
The first-line test resulted in a clinical sensitivity of 96.4% (95% CI; 82.3% to 99.4%), and specificity of 99.0% (95% CI; 94.7% to 99.8%), whereas the second-line test had a sensitivity of 100% (95% CI; 87.1% to 100%) and specificity of 98.4% (95% CI; 94.2% to 99.5%). Using the OTA, 78/98 (80%) of initially positive SARS-CoV-2 IgG results were confirmed with a second-line test, while 11/42 (26%) of previously diagnosed COVID-19 patients had no detectable antibodies as long as 94 days post PCR diagnosis.CONCLUSION:
Our results show that an OTA can be used to identify patients who require further follow-up due to potential SARS CoV-2 IgG false positive results. In addition, serological testing may not be sufficiently sensitive to reliably detect prior COVID-19 infection.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Immunoglobulin G
/
COVID-19 Serological Testing
/
SARS-CoV-2
/
COVID-19
/
Antibodies, Viral
Type of study:
Cohort study
/
Diagnostic study
/
Experimental Studies
/
Observational study
/
Prognostic study
Topics:
Long Covid
Limits:
Adolescent
/
Adult
/
Aged
/
Humans
/
Middle aged
/
Young adult
Country/Region as subject:
North America
Language:
English
Journal:
Clin Chem
Journal subject:
Chemistry, Clinical
Year:
2020
Document Type:
Article
Affiliation country:
Clinchem
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