Effective April 22, 2024, Clinical Pathology Laboratories (CPL) is pleased to announce automated reflex referral for HLA-B27 results determined to be indeterminate results by flow cytometry.
Human leukocyte antigen B27 (HLA-B27) is associated with ankylosing spondylitis, Reiter syndrome and other seronegative spondyloarthropathies. The antigen is routinely assessed by flow cytometry, an antibody-based technique used to analyze and quantify specific cell markers. Alternatively, this may be assessed with PCR amplification and molecular probing of the HLA class I genes (Molecular HLA-B27 test). Flow cytometry may result as NEGATIVE or POSITIVE with rare INDETERMINATE results for signal near flow cytometry cutoff. Previously, the laboratory relied on a second antibody system to assess INDETERMINATE results; however, that confirmation system did not fully resolve INDETERMINATE results and is no longer suitable for use. For specimens received in suitable collection tubes, CPL will automatically reflex confirmatory testing by PCR with Fluorescent Probe methodology to be performed by Sonic Reference Laboratory.
Further Detail:
- K2 EDTA anticoagulated tubes (lavender top) are suitable for flow cytometry and molecular testing and are preferred for testing.
- Sodium heparin tubes (green top) are suitable for flow cytometry but not molecular testing. INDETERMINATE results from sodium heparin tubes (green top) will require re-collection for confirmatory testing.
- CPT Codes
- CPT code for Flow Cytometry HLA-B27 is 86812
- CPT code for reflex Molecular HLA-B27 is 81374. For cases that trigger reflex molecular HLA-B27 testing, flow cytometry charges will be suppressed, and molecular charges will apply.
- Important note: Reflex molecular HLA-B27 requires prior authorization from certain insurance companies. For accessions that trigger reflex, customer service will contact the ordering entity to initiate prior authorization.
Changes to Order Codes:
Order Code: 4864 Reporting Title: HLA-B27 Specimen Type: WHOLE BLOOD Preferred Specimen Requirements:
Acceptable Specimen Requirements:
Minimum Specimen Volume:
Ref. Range and Units of Measure:
Specimen Stability:
Rejection Criteria: SAMPLES COLLECTED IN LITHIUM HEPARIN TUBE CPT Code:
LOINC: 26028-1 |
Order Code: 4864 Reporting Title: HLA-B27 BY FLOW RFLX Specimen Type: WHOLE BLOOD Preferred Specimen Requirements:
Acceptable Specimen Requirements:
Minimum Specimen Volume:
Ref. Range and Units of Measure:
Specimen Stability: SAMPLES COLLECTED IN LITHIUM HEPARIN TUBE
Rejection Criteria: SAMPLES COLLECTED IN LITHIUM HEPARIN TUBE CPT Code:
LOINC: 26028-1 |
Current | New |
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Report Messaging for Specimens with Indeterminate Results:
If specimen is collected in an EDTA tube:
If specimen is collected in sodium heparin tube: