HLA-B27
HLA-B27 test · HLA-B27 antigen · genetic test for back pain
This blood test checks for a special marker protein on your cells. It is more common in people with inflammation of the spine and joints.
For long-lasting lower back pain, especially in the morning and at rest, or for inflammation of the joints or eyes.
⏱ Duration: the blood draw usually takes 5 minutes; results usually come in a few days
Be sure to tell your doctor
How to prepare
- Food. You usually do not need to fast. If you are having other tests at the same time, check with the lab.
- Medicines. Do not stop anything on your own. Medicines do not affect this test.
What to bring
- Your referral
- Your ID
How it goes
- You sit down, and a band is tied above your elbow
- The skin is wiped with antiseptic
- Blood is taken from a vein into a tube
- The band is removed, and a cotton pad is pressed on the spot
What you'll feel
- A quick prick, like a pinch
- Sometimes slight dizziness. Tell the nurse, and they will help you lie down
Afterwards
- Press the cotton pad for 3 to 5 minutes
- Results usually come in a few days
- A positive result is not a diagnosis. Many people with this marker are healthy
- The doctor reads the test together with your symptoms and scans
Common questions
I have HLA-B27. Am I sick?
Not necessarily. Many healthy people have this marker. A diagnosis is made only from symptoms, an exam, and scans.
Do I need to repeat the test?
No. It is something you are born with. It does not change.