Serum or Plasma Immunoassay for Anti-SARS-CoV-2 Nucleocapsid Antibodies (Qualitative)
This test detects antibodies in your blood that your immune system produces in response to the SARS-CoV-2 virus, which causes COVID-19. It helps determine if you had an infection at some point, even if you didn’t experience symptoms.
["This test checks for past exposure to COVID-19 by measuring antibodies your body made to the virus’s core protein."]
Key facts at a glance
- LOINC
- 16982-1
- Short code
- HTLV I+II Ab Ser Ql IB
- Synonyms
- HTLV I+II Ab Ser Ql IB
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ib
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test looks for antibodies called anti-nucleocapsid antibodies. These antibodies develop after your immune system encounters the SARS-CoV-2 virus. They are part of your body’s immune response and can indicate previous infection, even if symptoms were mild or absent. This test is qualitative, meaning it only tells you if antibodies are present or not, rather than how much.
Why Your Doctor Might Order This Test
Doctors may order this test to confirm past COVID-19 infection in people who tested positive for the virus earlier but are now symptom-free. It can also be used in research, screening programs, or to monitor immune responses in certain populations. This test is not used to diagnose current infection or replace other COVID-19 tests like PCR or antigen tests.
How the Test Works
A small blood sample is taken from your arm and sent to a lab. The lab uses an immunoassay method to detect the presence of anti-nucleocapsid antibodies in your serum or plasma. This method involves mixing your blood sample with a known substance that binds to the antibodies if they are present, triggering a visible reaction that confirms their presence.
What to Expect Before the Test
There are no special preparations needed for this test. You can eat, drink, or take medications as usual on the day of the test. If you’re on blood thinners, let your doctor know before the test to discuss any precautions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Anti-Nucleocapsid Antibody Test (Qualitative)
Frequently asked questions
How long does it take to get the results of this test?
Can this test be used to confirm a current COVID-19 infection?
What does a positive result mean for my health?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy