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False positive and false negative reactions in HLA B-27 antigen testing
Transfusion
|March 1, 1979
Summary
Newly available HLA B-27 antiserum allows broader testing, but interpretation requires care. High rates of false positives and negatives, including cross-reactions, necessitate using multiple antisera for accurate HLA B-27 detection.
Area of Science:
- Immunogenetics
- Clinical Immunology
Background:
- The Human Leukocyte Antigen (HLA) B-27 antigen is associated with several autoimmune diseases.
- Commercial availability of HLA B-27 antiserum has expanded testing accessibility for laboratories.
- Previous experience in HLA typing was a barrier to B-27 antigen testing.
Purpose of the Study:
- To evaluate the reliability of newly available HLA B-27 antiserum in a clinical laboratory setting.
- To determine the frequency of false positive and false negative reactions in HLA B-27 testing.
- To identify causes of inaccurate HLA B-27 test results.
Main Methods:
- Testing of 100 patient specimens using commercially available HLA B-27 antiserum.
- Analysis of reaction patterns to identify false positive and false negative results.
- Investigation of cross-reactivity between HLA B-7 and B-27 antisera.
Main Results:
- Out of 100 specimens, 30 tested positive and 70 negative for HLA B-27.
- 10% of initially positive specimens (3/30) did not react with all tested antisera.
- 41% of initially negative specimens (29/70) showed false positive reactions with B-27 antisera.
- HLA B-7 antigen cross-reactivity was a significant cause of false positives (13/15 B-7 positive, B-27 negative specimens).
Conclusions:
- Newly available HLA B-27 antiserum can lead to frequent false positive and false negative results.
- Cross-reactivity, particularly with HLA B-7, is a major source of error.
- Using multiple B-27 antisera is crucial for accurate and valid HLA B-27 testing.