SARS-CoV-2 Semi-Quantitative IgG Antibody, Spike

CPT: 86769
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  • COVID-19
  • S protein
  • Severe Acute Respiratory Syndrome (SARS)
  • Spike

Special Instructions

On May 19, 2021, the FDA issued a safety communication reiterating that "antibody testing should not be used to evaluate a person's level of immunity or protection from COVID-19 at any time, and especially after the person received a COVID-19 vaccination." Visit for more information.

Expected Turnaround Time

1 - 3 days

Related Documents

For more information, please view the literature below.

Dynamics of SARS-CoV-2 and the Adaptive Immune Response White Paper

Specimen Requirements


Serum or plasma


0.5 mL

Minimum Volume

0.4 mL (Note: This volume does not allow for repeat testing.)


Gel-barrier tube or serum from red-top tube or serum transfer tube, or plasma from lithium heparin or EDTA tube


Standard aseptic procedures

Storage Instructions

Room temperature

Stability Requirements



Room temperature

14 days


14 days


14 days

Freeze/thaw cycles

Stable x3

Patient Preparation

No special preparation required.

Causes for Rejection

Grossly hemolyzed or lipemic samples and samples containing particulate matter or exhibiting obvious microbial contamination

Test Details


Qualitative and semi-quantitative detection of IgG antibodies to SARS-CoV-2 in human serum and plasma. This assay is intended for use as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection. Samples should only be tested from individuals that are 15 days or more post symptom onset. IgG antibodies to SARS-CoV-2 are generally detectable in blood several days after initial infection, although the duration of time antibodies are present post-infection is not well characterized. Individuals may have detectable virus present for several weeks following seroconversion.


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.

At this time, it is unknown for how long antibodies persist following infection and if the presence of antibodies confers protective immunity.

This test has not been FDA cleared or approved. This test has been authorized by FDA under an Emergency Use Authorization (EUA). This test is only authorized for the duration of the declaration that circumstances exist justifying the authorization of emergency use of in vitro diagnostics for detection and/or diagnosis of COVID-19 under Section 564(b)(1) of the Act, 21 U.S.C. 360bbb-3(b) (1), unless the authorization is terminated or revoked sooner. This test has been authorized only for detecting the presence of antibodies against SARS-CoV-2, not for any other viruses or pathogens.

False positive results may occur due to cross-reactivity from pre-existing antibodies or other possible causes.


Chemiluminescent Immunoassay (CLIA)

Reference Interval


Additional Information

The incubation period for COVID-19 ranges from 5 to 7 days. Current literature suggests that detectable IgG-class antibodies against SARS-CoV-2 develop approximately 8 to 11 days following onset of symptoms. Correlation with epidemiologic risk factors and other clinical and laboratory findings is recommended. A positive serological result is not diagnostic but indicates that an individual has likely been infected with SARS-CoV-2 and produced an immune response to the virus. It is not known at this time whether detectable antibody correlates with immunity. A negative serologic result indicates that an individual has not developed detectable antibodies at the time of testing. While contingent on a variety of factors, this could be due to testing too early in the course of infection, the absence of exposure to the virus, or the lack of adequate immune response, which can be due to conditions or treatments that suppress immune function.

∗FDA-authorized Fact sheets for patients and providers can be accessed at the following link:


Coronavirus Disease 2019 (COVID-19). Centers for Disease Control and Prevention web site. Accessed March 2020.
Policy for Diagnostic Tests for Coronavirus Disease-2019 during the Public Health Emergency. Immediately in Effect Guidance for Clinical Laboratories, Commercial Manufacturers, and Food and Drug Administration Staff: March 2020. US Food & Drug Administration web site. Accessed March 2020.
Woo PC, Lau SK, Wong BH, et al. Differential Sensitivities of Severe Acute Respiratory Syndrome (SARS) Coronavirus Spike Polypeptide Enzyme-Linked Immunosorbent Assay (ELISA) and SARS Coronavirus Nucleocapsid Protein ELISA for Serodiagnosis of SARS Coronavirus Pneumonia. J Clin Microbiol. 2005 Jul;43(7):3054-3058.16000415
Yu F, Le MQ, Inoue S, et al. Recombinant truncated nucleocapsid protein as antigen in a novel immunoglobulin M capture enzyme-linked immunosorbent assay for diagnosis of severe acute respiratory syndrome coronavirus infection. Clin Vaccine Immunol. 2007 Feb;14(2):146-149.17202310


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
164055 SARS-CoV-2 Antibody, IgG 94563-4 164083 SARS-CoV-2 Semi-Quant IgG Ab AU/mL 94505-5
164055 SARS-CoV-2 Antibody, IgG 94563-4 164084 SARS-CoV-2 Spike Ab Interp 94661-6

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