Test Code #


CPT Code(s) #


Test Name

SARS-CoV-2 Total Nucleocapsid Antibody (IgG, IgA and IgM)

If Profile, Includes Tests:


Disease Name:


Type of Study:

Serum Studies





Reference Range:

<0.8 Negative
0.8 - <1.0 Equivocal
>/= 1.0 Positive




Assays are performed twice per week. Report availability is within 3-5 days from the time of specimen receipt.

Specimen Requirements:

Collect 5-10 ml of blood in a red top or serum separator tube(preferred). If possible, separate serum from clot and place into red capped tube provided with Beutner Laboratories collection kits. If separation facilities are not available, the blood can be sent in the tube used for collection.

Sample Stability:

Transport the specimen at ambient temperature. If stored prior to shipment, it is stable refrigerated (2-8°C) for 7 days and frozen (-20°C or lower) up to one year.

Clinical Relevance:

SARS-Cov-2 total antibody assay detects IgM, IgG and IgA antibodies to nucleocapsid proteins of SARS-CoV-2 virus. A Positive result by this assay indicates recent or prior exposure to the virus. False positive results may occur with this assay due to cross reactivity from pre-existing antibodies or other possible causes. A negative or equivocal finding does not preclude acute infection. If acute infection is suspected, direct testing for SARS-CoV-2 is indicated.

Antibodies to SARS-CoV-2 are generally detectable in blood several days after infection, though the duration of time the antibodies are present post infection is not well characterized. It is unknown how long antibodies to SARS-CoV-2 will remain present in the blood after infection and it is not known if they confer immunity to infection.

The positive percent agreement in 51 serum specimens collected between 2-42 days post onset of clinical symptoms compared to SARS-CoV-2 RT-PCR was 92.16% and negative percent agreement is 99.56%.(1) Another study reported a specificity and sensitivity of 97.4% and 94.9% for total antibodies using the adapted cut‐offs (≥ 0.8) with this assay.(2)


(1) Platelia SARS-CoV-2 Total Ab package insert, Bio-Rad Laboratories, Inc.
(2) Tré-Hardy M, Wilmet A, Beukinga I, Favresse J, Dogné JM, Douxfils J, Blairon L. Analytical and clinical validation of an ELISA for specific SARS-CoV-2 IgG, IgA, and IgM antibodies. J Med Virol. 2021 Feb;93(2):803-811.

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