Serum/Plasma Immunoassay for Anti-SARS-CoV-2 Nucleocapsid Antibodies (Qualitative)
This test measures whether your immune system has produced antibodies against the SARS-CoV-2 virus’s nucleocapsid protein, which helps determine past infection with COVID-19.
["This test helps confirm if you’ve been infected by the virus that causes COVID-19, even if you no longer have active symptoms."]
Key facts at a glance
- LOINC
- 14023-6
- Short code
- HTLV I+II p28 Ab Ser Ql IB
- Synonyms
- HTLV I+II p28 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
Why This Test Is Done
Doctors may order this test to investigate a history of COVID-19 symptoms, confirm past infection for research or vaccine studies, or assess immune response after recovery. It can also be used in screening for antibody presence in blood donations or research settings.
How the Test Works
A small blood sample is taken from your arm and sent to a lab. The test uses an immunoassay method to detect antibodies specific to the nucleocapsid protein of SARS-CoV-2. The result is qualitative, meaning it only indicates whether antibodies are present or not.
What to Expect Before the Test
No special preparation is needed. You may have a slight bruise or soreness at the injection site, but this usually fades quickly. If you’re on blood-thinning medication, let your doctor know before the test.
What to Expect After the Test
You can return to your normal activities immediately. If you experience excessive bleeding, swelling, or signs of infection (like fever or redness), contact your healthcare provider right away.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Positive results indicate the presence of antibodies against the nucleocapsid protein, suggesting prior infection with SARS-CoV-2. These antibodies can persist for months or years, helping track immunity or exposure history. However, they do not distinguish between infections from different variants or indicate current infection status. Negative results mean no detectable antibodies were found, which may mean you were never infected or the test was taken too early after exposure.
Short name
Anti-Nucleocapsid Antibody Test
Frequently asked questions
When Might I Need This Test?
What Does a Positive Result Mean?
What Does a Negative Result Mean?
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