Published on April 27, 2020

COVID IgG (SARS CoV-2) Nucleocapsid Antibody

Tube Type

Test ID LAB19414
CPT Code(s) 86769
Group/Individual Test Individual
Laboratory Clinical Immunology
Tube Station 30
Specimen Routine:

Serum: 3 ml blood/Serum Separator Tube/Gold Top

Plasma: 3 ml blood/EDTA (Purple Top) Tube

Availability Routine: Monday-Friday
STAT: n/a
Turnaround Time 1-3 Days (Routine)
Reference Range Normal: Non-Reactive; See Important Comments.

Specimens submitted for detection of IgG antibodies to SARS-CoV-2 (COVID 19) nucleocapsid antigen are tested using a chemiluminescent microparticle immunoassay (CMIA). The CMIA provides qualitative detection of SARS-CoV-2 IgG antibodies on the Abbott Architect instrument. Results are reported as nonreactive or reactive.

The Abbot SARS-CoV-2 IgG test has Emergency Use Authorization by the FDA as of April 26, 2020. The manufacturer’s performance specifications indicate a negative percent agreement of 99.63% based on analysis of 997 pre-COVID-19 outbreak samples and 73 samples from patients with other respiratory illnesses who tested negative by SARS-CoV-2 PCR. Positive percent agreement (PPA), based on testing of 122 samples from 31 patients who tested positive by a SARS-CoV-2 PCR assay, varies by the time after disease onset. PPA for samples collected three to seven days after onset was 25%. The PPA on samples collected eight to fourteen days after onset was 86.36% and 100% for samples collected greater than or equal to 14 days after onset.

This test detects IgG antibodies to a recombinant SARS-CoV-2 nucleocapsid protein

Negative results do not rule out SARS-CoV-2 infection, particularly in those who have been in contact with the virus. Follow-up testing with a molecular diagnostic should be considered to rule out infection in these individuals.

Positive results do not rule out the potential for re-infection or indicate immunity to SARS-CoV-2 infection.

This test is not recommended for samples collected less than seven days after onset due to low sensitivity in the first week after onset.

Results from antibody testing should not be used as the sole basis to diagnose or exclude SARS-CoV-2 infection or to inform infection status.

Positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43, or 229E.

This test does NOT detect antibodies induced by currently approved COVID-19 vaccines.

Fact Sheets for Patients and Providers contain further information on antibody testing for SARS-CoV-2

Reviewed by Christopher Parker on January 14, 2022

Note: Reference ranges provided on this web site are for guidance only, and may not reflect the most recent changes. Refer to laboratory reports for current reference data.

UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514