All tests › Infection and immunity tests

SARS-CoV-2 antibody

Infection and immunity tests · also printed as COVID antibody, SARS-CoV-2 IgG, COVID-19 antibody, SARS-CoV-2 spike antibody, Anti-spike IgG

Typical UK adult rangeExpected result: Positive

Positive spike antibody is the expected result after vaccination. Numeric values in U/mL or BAU/mL may be printed.

What this test measures

This test detects antibodies to the COVID-19 virus, most often to the spike protein. Vaccination produces spike antibodies; only infection produces nucleocapsid antibodies.

Why doctors request it

Used in research, in some immune-suppressed patients, and on private panels. It does not show current infection.

What commonly pushes it up

Vaccination (spike antibody)
Past infection (spike and nucleocapsid)

What commonly pushes it down

Waning over months
Immune suppression

Everyday reasons for a value outside the range

Results can be equivocal and are then repeated
Recent vaccination or infection elsewhere can occasionally give a weak positive

About the sample

No fasting needed.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

Got a report with SARS-CoV-2 antibody on it?

Upload a photo or PDF and see every line against the range your lab printed, explained in plain English. First report free.

Read my report free

This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.