Serum or Plasma Substance Concentration by Immunoassay (for a specific protein marker)
This test measures the amount of a particular protein in your blood, often used to detect or monitor certain conditions affecting the immune system or organs.
["Helps identify or track protein-related health issues with a simple blood draw."]
Key facts at a glance
- LOINC
- 25587-7
- Short code
- CGA
- Synonyms
- CgA SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube; plasma may be collected in EDTA or heparin tubes depending on assay requirements
- Units
- N/A
- Ref low
- 0
- Ref high
- 93
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–99 years
- Method
- Enzyme-Linked Immunosorbent Assay (ELISA) or Chemiluminescent Immunoassay (CLIA)
- CPT
- 86316
- SNOMED
- 104656006
- Specimen volume
- 1.0 mL of serum or plasma
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 48 hours; Frozen (-20°C or below): 3 months; avoid repeated freeze-thaw cycles
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 24–72 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms like unexplained fatigue, weight changes, or organ issues (e.g., liver, kidney). It could also be part of routine monitoring for conditions like autoimmune diseases, infections, or certain cancers.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves a fasting sample. Wear comfortable clothing and plan for a short visit to a lab or clinic.
During the Test
A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it only takes a few minutes. The blood is then sent to a lab for analysis using an immunoassay method to detect and measure the protein.
What the Results Mean
Results show the concentration of the protein in your blood. Elevated or low levels may signal underlying health concerns, but interpretation depends on your symptoms, medical history, and other test results.
Reference range
Reference range is typically < 93 ng/mL (or < 20 nmol/L when reported in SI units); values may vary by laboratory and assay manufacturerN/A
No special patient preparation required. Fasting is not necessary. Patients taking proton pump inhibitors (PPIs) should discontinue use for 1-2 weeks prior to testing if possible, as PPIs can falsely elevate Chromogranin A levels.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test plays a key role in diagnosing or managing conditions like chronic inflammation, organ dysfunction, or immune system disorders. For example, it might help confirm a diagnosis of a rare protein-related disorder or assess how well a treatment is working.
Short name
Protein Marker Screening
Frequently asked questions
What does a ‘positive’ or ‘abnormal’ result mean?
Can I eat or drink before this test?
How often will I need 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 14, 2026. · Read our editorial policy