COVID IgG Antibody Testing via LabCorp
SARS-CoV-2 (COVID-19) Serological Testing via LabCorp
LabCorp has provided guidance as to the timing of when antibodies to SARS-CoV-2 are detectable after exposure:
IgG – Detectable 10-14 days after exposure to SARS-CoV-2
What does a serology positive mean?
- A positive result means that the patient was exposed in the past and has developed the detected antibody.
- A positive result does not prove that a patient is immune to the virus.
- A positive result does not indicate that the patient is not currently infectious to others.
- A positive result does not indicate that the patient currently has the virus in his/her system.
- There may be a false positive if a patient was exposed to another non‐SARS‐CoV‐2 coronavirus strain. These non‐SARS‐CoV‐2 strains are common and are one cause of the common cold. We don’t have the numbers today on how often the false positives due to cross reactivity may occur.
What does a negative serology mean?
- A negative result means that no antibody to the virus was detected in the sample tested or if low level of antibody is present, it is present at a level below the assay’s detection limit
- A negative result does not mean that the patient is free of the virus.
- A negative result does not mean that the patient is not currently infected and infectious to others, especially if the individual has come in contact with the virus. Follow‐up testing with a NAA test (Test Code: 139900) should be performed in these individuals.
- Individuals who are immunosuppressed or who are on drugs that suppress the immune system may test negative despite being exposed to SARS‐CoV‐2.