HLA B27, Flowcytometry is a useful screening test to measure the HLA B27 antigen level in your blood. It can also be performed after and during the treatment of the autoimmune disorder. HLA B27, also known as human leukocyte antigen, is a common gene present in people with inflammatory diseases and certain types of arthritis. There are hundreds of HLA genes, but one gene, HLA-B27, is associated with a family of rheumatic diseases called spondyloarthropathies.

What is a HLA B27, Flowcytometry Test?  

HLA B27, Flowcytometry is a useful screening test to measure the HLA B27 antigen level in your blood. It can also be performed after and during the treatment of the autoimmune disorder. HLA B27, also known as human leukocyte antigen, is a common gene present in people with inflammatory diseases and certain types of arthritis. There are hundreds of HLA genes, but one gene, HLA-B27, is associated with a family of rheumatic diseases called spondyloarthropathies.  

These diseases cause inflammation, pain, and stiffness in the spine, entheses, and hip joints. HLA-B27 is also found in people who have eye inflammation uveitis or inflammatory bowel disease. Almost 80-90% of people with ankylosing spondylitis get positive test results for HLA-B27. Around 10-20% of people with proven ankylosing spondylitis get negative test results for HLA B27. 

HLA B27, Flowcytometry test is suggested for people whose symptoms suggest AS. The doctor generally orders this test when they suspect any disease related to the autoimmune disorder, including isolated peripheral enthesitis, Reiter's syndrome or reactive arthritis, and ankylosing spondylitis.  

What is the purpose of the HLA B27 Flowcytometry Test? 

HLA B27, Flowcytometry test is performed to determine the level of a genetic marker and protein called human leukocyte antigen B27. The test is also performed during organ transplant procedures to match the patient's tissue with the donated tissue. The test can also be used in paternity cases. For example, paternity can be proven if the father and child have the same unusual HLA genotype. 

What does the HLA B27, Flowcytometry test diagnose? 

HLA B27, Flowcytometry test checks for a specific type of protein on your white blood cell that could lead to Ankylosing Spondylitis (AS), an autoimmune disease. This test is used to check whether these disorders: 
 

• Bone inflammation and bone degeneration 
• Autoimmune disorder 
   

Your doctor may order this test to assess your chances of developing an autoimmune disease. They may also use it to confirm the diagnosis of Ankylosing Spondylitis.  

Why do you need an HLA B27, Flowcytometry test? 

Your healthcare provider may ask you to go for the HLA B27, Flowcytometry test if you have the following symptoms: 
 

• Joint pain 
• Swelling or stiffness in the spine, chest, or neck 
• Severe fatigue 
• Eye inflammation
   

You may also be ordered to undergo this test if you have any of the autoimmune disorders or diseases: 
 

• Acute Anterior uveitis 
• Sacroiliitis associated with psoriasis 
• Juvenile rheumatoid arthritis  
• Sacroiliitis related to inflammatory bowel diseases 
• Reiter's syndrome or Reactive arthritis 
• Ankylosing Spondylitis 

Your doctor may also suspect you have Ankylosing Spondylitis if you are a young male adult because this disease is more common in males under age 40. If the test results are positive for the antigen, it doesn't mean you are affected by these diseases. Before making a final diagnosis, the patient's medical background and context must be considered. The test can also be conducted as a part of other tests, including a rheumatoid factor with either a C-reactive protein test or an erythrocyte sedimentation rate. 

Preparation and procedure required for the HLA B27, Flowcytometry test 

No special preparation is required for the HLA B27, Flowcytometry test. You don't need to stop taking food or drink before undergoing this test. But you should consult your doctor to see if you need to stop taking any drugs or medications before this test. Stop doing any vigorous activity before this test, including heavy lifting and exercise.  

The HLA B27, Flowcytometry test is like any other blood test. During this test, the technician will draw a blood sample from the vein on the back of your hand or the inside of your elbow. The area where the blood will be drawn will be disinfected using an antiseptic. An elastic band will be tied on your upper arm to make the blood collection procedure easier. A needle will be inserted, and blood will be drawn in a vial or test tube. You may feel a mild pain or tingling sensation when the needle is inserted. The needle will be withdrawn gently, and the site will be covered with a bandage. Since the size of the arteries and veins differ in everyone, multiple punctures may be needed during the blood collection process.  

You should avoid strenuous activities after the test to prevent bleeding. If you experience bleeding or stiffness at the site where the blood was drawn, immediately inform your healthcare provider.  

Understanding the HLA B27, Flowcytometry test results 

The HLA B27, Flowcytometry test will indicate the absence or presence of HLA B27. The test result will be either negative or positive. A negative HLA B27, Flowcytometry test result indicates the absence of HLA-B27 in your blood, though this does not rule out the possibility of having an autoimmune disorder. If your test is positive, it indicates the presence of HLA-B27 in your blood. A positive test result can be a matter of concern, but it doesn't mean you have psoriatic arthritis, ankylosing spondylitis, or other autoimmune diseases. The healthcare provider will interpret the results considering your gender, age, symptoms, and health history.  

If your HLA-B27 test result is positive and your doctor confirms you have an autoimmune disease or ankylosing spondylitis, you will be referred to a rheumatologist who specializes in musculoskeletal conditions, inflammatory disorders, and autoimmune diseases in people of all ages.