SARS-CoV-2 Nucleocapsid Protein (ORF1ab) Antigen Test, Respiratory Specimen
This test detects the presence of SARS-CoV-2 nucleocapsid protein in your respiratory secretions, such as nasal or throat swabs. It helps identify if you may have an active infection with the virus responsible for COVID-19.
["This test can quickly determine if you might be contagious with COVID-19."]
Key facts at a glance
- LOINC
- 97104-4
- Short code
- SARS-CoV-2 ORF1ab U resp NAA+probe-aCnc
- Synonyms
- SARS-CoV-2 ORF1ab U resp NAA+probe-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
- probe-amp-tar
- CPT
- 86430
- 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
How the Test Works
The test uses a specialized probe to detect specific viral proteins in your respiratory sample. If the virus is present, the test will show a positive result, indicating possible infection. This method is designed to be rapid and often provides results within minutes.
What to Expect Before the Test
You may have a nasal or throat swab inserted to collect a sample of respiratory secretions. This is usually quick and painless. Avoid eating, drinking, or smoking for at least 30 minutes before the test if instructed by your healthcare provider.
What to Expect After the Test
After the test, you may experience mild discomfort or irritation from the swab. You can resume normal activities immediately. Follow any specific instructions your healthcare provider gives you regarding follow-up care.
When This Test Might Be Ordered
Your healthcare provider may order this test if you have symptoms of COVID-19, such as fever, cough, shortness of breath, or loss of taste/smell. It may also be used as part of screening in high-risk settings or for monitoring exposure.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A positive result suggests the presence of SARS-CoV-2 nucleocapsid protein, indicating an active infection. This test is particularly useful for rapid diagnosis and guiding isolation and treatment decisions. However, it may not detect all cases of infection, especially if the virus levels are low. A negative result does not definitively rule out infection, particularly if symptoms persist or if testing was done too early in the illness.
Short name
Nucleocapsid Antigen Test (Respiratory)
Frequently asked questions
What does a positive result mean?
Can I get this test at home?
How soon after infection can I get a positive result?
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