HLA B-27 - FLOW CYTOMETRY
🔬 Standard Screening Method📋 Test Specifications
- Report Turnaround: Next Day Evening (Closed Sundays).
- Sample Required: EDTA Whole Blood (Purple Top).
- Methodology: Flow Cytometry (FCM).
- Fasting Required: No.
- Accuracy: Good for initial screening.
What is the HLA-B27 Flow Cytometry Test?
This is the standard screening test used to detect the HLA-B27 antigen on the surface of white blood cells. It uses Flow Cytometry technology, which utilizes lasers to count and analyze cells containing this specific protein marker.
This test is faster and more affordable than the PCR method, making it the preferred first-line test for diagnosing autoimmune conditions like Ankylosing Spondylitis.
🔴 Why is this test prescribed?
HLA-B27 is a genetic marker present in about 90% of patients with Ankylosing Spondylitis. Doctors recommend this test if you are suffering from:
- Chronic lower back pain (lasting more than 3 months).
- Morning stiffness that improves with exercise.
- Recurring eye inflammation (Uveitis).
- Joint pain and swelling in the hips or knees.
Flow Cytometry vs. PCR: What's the Difference?
It is important to understand which test you are booking:
- Flow Cytometry (This Test): Detects the protein on the cell surface. It is fast and cost-effective. Rarely, it may cross-react with other markers (like HLA-B7), leading to borderline results.
- PCR (Molecular): Detects the DNA/Gene directly. It is more expensive but acts as a confirmatory test if Flow Cytometry results are unclear.
When is this Test Recommended?
This test aids in the diagnosis of a group of diseases called Spondyloarthropathies, including:
- Ankylosing Spondylitis (AS): Inflammation of the spine.
- Reactive Arthritis (Reiter's Syndrome): Joint pain triggered by infection.
- Psoriatic Arthritis: Arthritis associated with psoriasis.
Test Procedure
- Collection: A standard blood draw from the vein (3ml).
- Preparation: No special preparation or fasting is needed.
- Report: Since this method is automated, reports are generally available by the next evening.
Frequently Asked Questions (FAQ)
No, you can eat and drink normally before this test.
Sometimes, Flow Cytometry cannot clearly distinguish the HLA-B27 marker from similar markers. In such cases, the doctor will recommend the HLA-B27 PCR test for 100% confirmation.
The report is generated by the Next Day Evening. Note: Samples collected on Sunday are reported on Monday Evening.
Disclaimer: A Positive result indicates a genetic predisposition but does not confirm the disease by itself. Results must be correlated with clinical symptoms and X-rays.