Lab Test

HLA B27 Screen

HLA-Antigen B27, HLA-B27, HLA-B27 Screening Assay, Flow Cytometry, HLA B27 Screen

Test Codes

FB27G, EPIC: LAB6411


Flow Cytometry

Specimen Collection Criteria

Collect: One Lavender-top EDTA tube.
Also acceptable: One Yellow-top ACD tube or Green-top Sodium Heparin tube.

Physician Office/Draw Specimen Preparation

Maintain whole blood at room temperature (20-26°C or 68-78.8°F) prior to transport. Specimens must be received in the Laboratory within 48 hours of collection.

Preparation for Courier Transport

Transport: Whole blood, at room temperature (20-25°C or 68-77°F).

FedEx Shipping Instructions:
Transport 4 mL whole blood at room temperature. Specimen must be received within 48 hours of collection. 

Rejection Criteria

  • Specimens received greater than 48 hours post collection are acceptable with approval of the Flow Cytometry Laboratory manager or pathologist on service. 
  • This test will only be performed once in a lifetime for a patient. 

In-Lab Processing

Maintain at room temperature (20-26°C or 68-78.8°F) prior to testing.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 48 hours
Refrigerated (2-8°C or 36-46°F): 48 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Room Temperature (20-26°C or 68-78.8°F): 7 days


Royal Oak Flow Cytometry Laboratory


Monday, Wednesday, Friday.
Results available in 1-3 days.

Reference Range

Patients will be reported as negative or positive for HLA-B27 Antigen.

Test Methodology

Immunophenotyping by Multiparameter Flow Cytometry


This test is reported as positive or negative. If the result is in the equivocal range, the HLA test “HLA-B27 Genotyping (Spondyloarthropathies)” will be added on as a confirmatory test. A separate report will be issued. If the HLA laboratory is unable to confirm the result, the specimen will be reported as equivocal and a comment will be added: “Unable to confirm by HLA Laboratory molecular SPP testing. Recommend specimen redraw.”

Clinical Utility

Flow cytometric lymphocyte analysis has allowed for rapid and sensitive screening for the presence of HLA-B27, which may be valuable in the evaluation of patients with arthritic symptoms, as seen in ankylosing spondylitis. HLA-B27 positivity has been found to be highly associated with ankylosing spondylitis. Testing for the presence of the HLA-B27 antigen in a patient is used to assist in the diagnosis of ankylosing spondylitis and /or determine a genetic predisposition for ankylosing spondylitis.

CPT Codes



Last Updated


Microtainer® and Vacutainer® are registered trademarks of Becton, Dickinson and Company.
UroVysion® is a registered trademark of Abbott Laboratories. ThinPrep® is a registered trademark of Hologic, Incorporated.