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Test Code C19ABP SARS CoV 2 Antibody Panel - Covid 19 Antibodies

Important Note

The current applications and clinical utility for COVID-19 serology testing include:

  • Seroprevalence and epidemiological studies
  • Diagnosis of individuals who may have been infected more than 14 days before testing, after the virus may no longer be detectable by PCR or antigen tests
  • Distinguishing whether a patient’s positive SARS-CoV-2 PCR test represents current infection (serology test should be negative) or past infection (serology test should be positive)
  • Identification of individuals who may serve as potential convalescent plasma donors.

This serum antibody test should not be used for primary diagnosis of acute SARS-CoV-2 infection.  The preferred test for that is the direct viral testing (PCR) from a nasal pharyngeal swab. 

Additional information may be found in the February 2021 LabWire announcement (panel including spike antibody) or the  May 2020 LabWire announcement. (capsid antibody).

Additional Codes

Epic Test ID

LAB3778

Specimen Required

Container Type:

Optimal: 

Inpatient: Mint

STAT: Mint

Outpatient: Gold

Acceptable: Red Top or Green Lithium Heparin.

 
Optimal Collection Volume: 

4.5 mL; Full Tube
Collection Instructions:

Gently invert sample 5-6 times after collection.
Processing Instructions: 

1. Allow serum sample to clot for 30 minutes.

2. Centrifuge specimen within 2 hours of collection.

3. Specimen tubes without a gel barrier should have the serum or plasma aliquoted to a false bottom container after centrifugation.

4. Keep serum/plasma refrigerated until testing can be performed.

 

Methodology

This panel contains two tests:

  • Roche Elecsys immunoassay for the qualitative detection of nucleo-capsid antibodies (including IgG) to SARS-Cov-2. For additional details on this methodology please see this link. 
  • Roche Elecsys immunoassay for the semi-quantitative detection of spike protein antibodies (including IgG) to SARS-Cov-2. For additional details on this methodology please see this link

The panel also includes an interpretive comment indicating the likley patient history in regard to infection or vacination.

 

Specimen Transport Temperature

Refrigerate

Specimen Stability

Serum samples are stable:

                                            3 days at 15‑25 °C  

                                            7 days at 2‑8 °C

                                            28 days at ‑20 °C (± 5 °C).

Note: Plasma samples have the same stability, however due to the breakdown of fibrinogen, for an add-on test, they need to be poured off and re-spun before testing.

Day(s) Test Set Up

Daily, 24/7.

 

Performing Laboratory

Bronson Laboratory Services-Chemistry

Reference Values

Capsid Antibody: NOTE: The capsid antibody test does not become positive following Covid-19 vaccination.

Negative

A negative test result does not rule out the possibility of an infection with SARS‑CoV‑2.  Samples from the early phase of illness can yield negative findings. Therefore, this test cannot be used to diagnose an acute infection. Testing with a molecular diagnostic should be performed to evaluate for active infection in symptomatic individuals.  Note:  over time, serological titers may decline and eventually become negative.

Positive

Positive test results indicate  SARS-CoV-2 antibodies were detected.  Such results suggest recent or prior infection with SARS-Cov-2.  Correlation with epidemiologic risk factors and other clinical and laboratory findings is recommended. It is not known at this time if the presence of antibodies to SARS‑CoV‑2 confers immunity to reinfection.

 

 

Spike Antibody  NOTE: The spike antibody test  become positive following Covid-19 infection and/or vaccination.

Negative:   < 0.80 U/ml

 

Positive:   ≥ 0.80 U/mL

 

 

Interpretive Comment:

Combining the two tests into a panel allows for better determination of a patient’s serological picture:

 

Capsid Antibody

Spike Antibody

Status

Negative

 Negative

Indicates neither vaccination nor infection

Negative

 Positive

Indicates vaccination;  no evidence of infection

Positive

 Negative

Indeterminate.  Could be early post infection or possible non-specific false positive

Positive

 Positive

Indicates infection with or without vaccination

 

Limitations of the test continue to be our lack of knowledge of how long detectable antibodies persist in the patient following either infection or immunization.  We do not know what levels of antibodies indicate immunity or protection from infection, but preliminary studies suggest that the presence of anti-spike or anti-nucleocapsid IgG antibodies is associated with a substantially reduced risk of SARS-CoV-2 reinfection in the ensuing 6 months.

 

Test Classification and CPT Coding

86769 x 2