Serum/plasma concentration of a specific protein marker measured by immunoassay (e.g., for antibody detection)
This test measures the amount of a particular protein in your blood, often used to detect or monitor certain immune responses or conditions.
["This test helps identify immune system activity or potential infections/autoimmune conditions."]
Key facts at a glance
- LOINC
- 30169-7
- Short code
- CGA
- Synonyms
- CgA SerPl IA-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube for serum; Lavender-top (EDTA) or green-top (heparin) tube for plasma
- Units
- N/A
- Ref low
- 0
- Ref high
- 93
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (e.g., ELISA, Chemiluminescent Immunoassay, or Radioimmunoassay)
- CPT
- 86316
- SNOMED
- 104285007
- Specimen volume
- 1-2 mL of serum or plasma (minimum 0.5 mL)
- Stability
- Stable for 24 hours at room temperature, 7 days at 2-8°C, and up to 3 months at -20°C or below. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 50
- Lipemia max
- 100
- Icterus max
- 25
- TAT
- 24–72 hours
- Order
- routine
What This Test Measures
The test detects the presence and concentration of a specific protein in your serum or plasma. This protein could be an antibody (e.g., against a virus, bacteria, or self-antigens) or another marker related to inflammation, immune response, or disease activity. The method used is an immunoassay, which is highly sensitive and specific for identifying these proteins.
Why It’s Done
Your healthcare provider may order this test to diagnose or monitor conditions such as infections (e.g., viral or bacterial), autoimmune diseases (e.g., lupus, rheumatoid arthritis), allergies, or other immune-related disorders. It can also help assess immune function or response to treatments.
Sample Collection
A blood sample is drawn from a vein, typically in your arm. The blood is then processed to separate the serum or plasma for testing. This process is quick and usually done in a lab setting.
Test Preparation
No special preparation is needed for this test. You may continue with your normal activities, but avoid heavy exercise or eating a large meal before drawing blood if instructed by your provider.
Reference range
Generally < 93 ng/mL or < 100 ng/mL depending on assay manufacturer. Reference values vary by laboratory and assay platform. Always refer to the specific laboratory's reference range.N/A
No fasting required. Proton pump inhibitors (PPIs) should be discontinued for at least 1-2 weeks prior to testing if possible, as PPIs can falsely elevate Chromogranin A levels. Other medications that may interfere include H2 receptor antagonists and corticosteroids.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
What does a positive or abnormal result mean?
How long does it take to get results?
Can I fast before this test?
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 15, 2026. · Read our editorial policy