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Test Code LAB1230623 COVID-19 IgG Antibody

Clinical Information

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a positive-sense, single-stranded RNA virus that causes coronavirus disease 2019 (COVID-19). The COVID-19 IgG Antibody test is intended for the qualitative detection of IgG-class antibodies against COVID-19.  A positive IgG result indicates previous infection with COVID-19 but does not indicate immunity or protection against future infection.  Serology testing is recommended only for individuals at least 10-14 days either post-symptom onset or following an exposure to individuals with confirmed COVID-19 infection.  Patients tested prior to this time may be falsely negative for IgG antibodies.  Serology testing may be used to screen patients as donors of convalescent plasma for use as a therapeutic.  This test should not be used to detect acute COVID-19 disease.  Symptomatic patients suspected to have acute COVID-19 infection should be tested using a molecular assay.

Collection Instructions

Specimen Collection: Blood

 

Container(s): 5.0 mL Gold Top (SST)

Preferred Volume to Collect: 4.5 mL

Minimum Volume to Collect: 1.0 mL

Neonate Volume to Collect: N/A

Capillary collect ok? No

Microtainer acceptable: Yes

 

Collection Instructions:

  • Gently invert 8-10 times to mix clot activator with blood.

Processing Instructions (Laboratory, Outpatient or Off-site collection)

Processed Specimen: Serum

 

Centrifuge/Spin: Yes

Aliquot: No

 

Transport Temperature: Refrigerated

Processed Minimum Volume: 0.5 mL serum

 

Processing Intructions:

  • Allow blood to clot for 30 minutes in a vertical position and centrifuge within 2 hours.

Rejection Criteria

  • Gross hemolysis
  • Lipemia
  • Icterus

Specimen Stability

Ambient: 8 hours

Refrigerate: 3 days

Frozen: Unavailable

Laboratory Retention: 3 days

Test Frequency

Available daily, TAT 1-3 days

Reference Range

Negative

No IgG antibodies to SARS-CoV-2 detected. 

Negative results do not preclude SARS-CoV-2 infection.  Negative results may occur in serum collected too soon following infection, in immunosuppressed patients, or in some individuals with prior mild illness.  Most immunocompetent individuals with SARS-CoV-2 infection will develop detectable IgG-class antibodies approximately 10 days following onset of symptoms.  Patients tested prior to this time may be negative for IgG antibodies.  Follow-up testing with a molecular test is recommended in symptomatic patients.  Results from serologic testing should not be used as the sole basis to diagnose or exclude active and/or recent SARS-CoV-2 infection.  Results should be assessed in conjunction with the patient’s medical history, epidemiologic risk factors, clinical examination, and other laboratory findings.

 

Indeterminant

Repeat testing in 7 to 10 days may be considered to determine definitive serologic status.

 

Positive

SARS-CoV-2 IgG antibodies detected. 

Results suggest recent or prior infection with SARS-CoV-2.  Serologic tests should not be used to diagnose acute SARS-CoV-2 infection.  If acute infection is suspected, molecular testing for SARS-CoV-2 is suggested.  It is unknown for how long antibodies persist following infection and if the presence of antibodies confers protective immunity.  False positive results may occur, but are not expected, due to prior infection with other human coronaviruses (e.g. SARS-CoV-1, HKU1, NL63, OC43, 229E), from pre-existing antibodies, or other possible causes.  Results from serologic testing should not be used as the sole basis to diagnose or exclude active and/or recent SARS-CoV-2 infection.  Results should be assessed in conjunction with the patient’s medical history, epidemiologic risk factors, clinical examination, and other laboratory findings.

Performing Department

Chemistry and Immunochemistry

Performing Department Laboratory Location

Spectrum Health Regional Laboratory (SHRL BW), Grand Rapids, MI

Methodology

ELISA and ECLIA

CPT

86769

CDM Code

Unavailable

Epic Test ID

1230102243

Interface Order Alias

1230623

LOINC

94762-2

Reviewed Date

5/14/2020