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Serum or plasma substance concentration for anti-SARS-CoV-2 nucleocapsid protein antibodies (qualitative immunoassay)

Published: August 9, 2026Updated: August 16, 2026

This test checks if your immune system has produced antibodies against the nucleocapsid protein of SARS-CoV-2, the virus responsible for COVID-19. Antibodies may develop after infection or vaccination.

Quick summary

["Determines whether your body has made antibodies to past or recent COVID-19 exposure."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
14030-1
Short code
ENA SM+RNP Ab Ser IA-aCnc
Synonyms
ENA SM+RNP Ab Ser IA-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 Might Be Ordered

Your healthcare provider may recommend this test if you’ve had COVID-19 symptoms, were exposed to the virus, or if you’re recovering from a COVID-19 diagnosis. It can also help assess immunity after vaccination or monitor long-term effects of infection.

What to Expect Before the Test

No special preparation is needed. A blood sample is drawn from a vein in your arm, similar to other blood tests. You may feel a slight pinch, but it usually takes only a few minutes.

What the Test Results Mean

Positive results indicate the presence of antibodies, suggesting past infection or immune response. Negative results mean no detectable antibodies were found at this time. Results don’t confirm current infection but can help track immunity.

Common Reasons for Testing

This test is often used to confirm past COVID-19 infection, evaluate vaccine effectiveness, or assess immune response in high-risk groups. It’s not a diagnostic tool for active infection but supports broader health monitoring.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Understanding Antibody Levels

Short name

Anti-Nucleocapsid Antibody (Qualitative)

Frequently asked questions

How long do antibodies last after COVID-19?
Antibody levels can vary. Some may persist for months or years, while others decline over time. Your provider can discuss follow-up testing if needed based on your health status and risk factors.
Can this test detect COVID-19 symptoms?
No, this test does not diagnose active COVID-19. It only checks for antibodies, which are markers of past infection or immune response. Active infection is typically confirmed with viral tests like PCR or antigen tests.
What if my results are negative but I still feel sick?
Negative results mean no detectable antibodies at this time. You may still have active infection, so continue following health guidelines. If symptoms persist, consult your provider for further evaluation.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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