SARS-CoV-2 Antibody (Serum) – Total IgG and IgM by Turbidimetry
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’ve been exposed to the virus, even if you didn’t get sick.
["This test checks for past or possible recent COVID-19 infection by measuring antibodies in your blood."]
Key facts at a glance
- LOINC
- 33974-7
- Short code
- SARS-CoV Urb Ab Titr Ser
- Synonyms
- SARS-CoV Urb Ab Titr Ser
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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
Your healthcare provider may order this test if you’ve had symptoms of COVID-19, were exposed to someone with the virus, or if you’re in a setting where testing for past exposure is recommended. It can also help monitor immunity after vaccination or recovery.
What to Expect Before the Test
No special preparation is needed. You’ll likely have a simple blood draw from a vein in your arm. If you’re using blood thinners, let your provider know before the test.
What the Test Results Mean
Positive results indicate the presence of antibodies, suggesting you’ve likely been exposed to SARS-CoV-2. However, antibody levels can vary and may not always correlate with immunity. Negative results mean no detectable antibodies were found, but this doesn’t rule out past exposure.
How the Test Works
Blood is collected and analyzed using a method called turbidimetry, which measures how much light is blocked by antibodies in your serum. This helps determine their concentration.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Antibodies are part of your immune system’s defense. Detecting them can help confirm past infection, but they don’t guarantee immunity against future infection. Some people may develop antibodies after vaccination or natural infection, while others may not. This test is useful for research, screening, or monitoring but isn’t a substitute for current infection testing.
Short name
SARS-CoV-2 Antibody Test (Serum)
Frequently asked questions
What does a positive result mean?
Can antibodies protect me from getting COVID-19 again?
Is this test the same as a PCR test for active COVID-19?
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