SARS-CoV-2 (COVID-19) Testing Guide

TEST NAME INTENT OF USE CLINICAL INTERPRETATION OF POSITIVE RESULTS
SARS-CoV-2 RT-PCR/Swab Early detection Confirms diagnosis
Anti-SARS-CoV-2 IgM Acute infection Acute infection in progress, requires confirmation by PCR
Anti-SARS-CoV-2 IgA Current infection Current infection in progress, requires confirmation by PCR
Anti-SARS-CoV-2 IgG Past infection/Immunity Past infection, Immunity, negative results should be followed by PCR if indicated
SARS-CoV-2 Antigen Antigen early detection Confirms diagnosis, any negative test must be confirmed by PCR if indicated
TEST NAME PERIOD OF DETECTION SENSITIVITY SPECIFICITY FALSE POSITIVE
SARS-CoV-2 RT-PCR/Swab Initially/Onset HIGH HIGH LOW
Anti-SARS-CoV-2 IgM 5-7 days can stay up to 10-12 days LOW LOW HIGH
Anti-SARS-CoV-2 IgA 7-10 days, can stay longer LOW LOW HIGH
Anti-SARS-CoV-2 IgG After 12-21 days, stays longer HIGH HIGH LOW
SARS-CoV-2 Antigen Initially/Onset LOW HIGH LOW


Recommendation For Use

SARS-Cov-2 RT-PCR/Swab

For early (onset) detection of SARS-CoV-2 use Molecular testing (swab); alternatively, Antigen test can be used, but all negative tests must be retested by the Molecular method.

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Anti-SARS-CoV-2 IgG

For immunity evaluation use Antibody IgG assay only.

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Anti-SARS-CoV-2 IgM & Anti-SARS-CoV-2 IgA

No value or recommendation for use of IgM or IgA

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Serological or antibody tests should not be used to diagnose active infection
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