Anti-Citrullinated Protein Antibody (ACPA) Serum Test
This test measures antibodies against citrullinated proteins in your blood, which may indicate inflammation in the joints or connective tissues.
["Helps diagnose rheumatoid arthritis and other autoimmune conditions by detecting specific antibodies linked to joint damage."]
Key facts at a glance
- LOINC
- 53027-9
- Short code
- cCP Ab Ser-aCnc
- Synonyms
- cCP Ab Ser-aCnc
- Category
- coagulation
- 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
What Is This Test Used For?
This test is primarily used to help diagnose rheumatoid arthritis and assess whether your symptoms may be caused by an autoimmune condition. It can also be used to monitor disease activity in patients already diagnosed with rheumatoid arthritis or other related conditions like systemic lupus erythematosus or spondyloarthritis.
Why Might You Need This Test?
Your healthcare provider may recommend this test if you have symptoms such as joint pain, swelling, stiffness, or fatigue that suggest rheumatoid arthritis or another autoimmune disease. It may also be part of a routine check-up for patients with a family history of autoimmune disorders or those with unexplained joint issues.
How Is the Test Performed?
A blood sample is drawn from a vein, usually in your arm, by a healthcare professional. The blood is then sent to a lab for analysis. The test looks for the presence of antibodies that target citrullinated proteins, which are proteins modified by a chemical process called deamination.
What Do the Results Mean?
Positive results for ACPA antibodies suggest a higher likelihood of rheumatoid arthritis or related autoimmune conditions. However, having these antibodies alone does not confirm a diagnosis; other tests and clinical evaluation are needed. Results can also help track disease progression or response to treatment over time.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Anti-Citrullinated Protein Antibodies (ACPA) are strongly associated with rheumatoid arthritis, appearing in about 70% of patients with early disease. They are less common in other autoimmune conditions but can still be relevant in diagnosing or guiding treatment for conditions like spondyloarthritis or lupus. Detecting these antibodies helps healthcare providers tailor treatment plans, such as targeting specific inflammatory pathways or monitoring disease activity more precisely.
Short name
ACPA Antibody
Frequently asked questions
What Does a Positive or Negative Result Indicate?
Can This Test Be Used to Monitor Treatment?
Are There Any Risks or Side Effects from 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 16, 2026. · Read our editorial policy