P009 Utilisation of HLA-B27 testing at a UK district general hospital
Bibliographic record
Abstract
Abstract Introduction Ankylosing spondylitis (AS) is a chronic inflammatory condition that primarily affects the axial spine. It is associated with many extra articular manifestations including inflammatory bowel disease and anterior uveitis. It has a complex pathogenesis with a known genetic association with human leukocyte antigen-B27 (HLA-B27). This study aimed to assess the alignment of HLA-B27 testing across Epsom and St Helier University Hospitals NHS Trust (ESTH) with current guidance outlined by Choosing Wisely (Canada) and NICE guideline [NG65]. Secondary objectives included estimating the financial impact of low value testing and recommending actions to reduce unnecessary investigations. Case description A retrospective review was conducted on all HLA-B27 tests performed in June 2024 across both primary and secondary care. Data from the community setting included general practice and community physiotherapy. Data from the secondary care setting included review from all departments across both hospital sites at St Helier Hospital and Epsom General Hospital. The data collected was collated through an IT request with our regional pathology laboratory. The data was analysed independently by two resident doctors, and cross referenced for accuracy. Duplicate data was excluded. Both NICE [NG65] and Choosing Wisely (Canada) recommend referring patients to Rheumatology for evaluation of axial spondyloarthritis when back pain has persisted for more than three months and began before the age of 45. Additionally, both guidelines advise HLA-B27 testing if three other criteria are met, which may include lower back pain with onset before age 35, pain that improves with movement, and having a first-degree relative with spondyloarthritis. Using this we were able to assess compliance. Financial analysis was carried out using an average cost of £37.55 per test, based on the NICE guidance for Health Economics Report 2017, Appendix H. Discussion During the month of June 2024, a total of 76 HLA-B27 tests were conducted throughout primary and secondary care within the Epsom and St Helier University Hospitals NHS Trust (ESTH). Analysis of the test requests revealed that the majority (70%) originated from primary care physicians (GPs and community practice nurses), while consultant Rheumatologists accounted for the next largest group of requesters at 17%. The remaining 13% included physiotherapists and other speciality doctors outside of Rheumatology (Gastroenterology, Trauma & Orthopaedics, Ophthalmology, Paediatrics and Acute Medicine). The demographic profile of patients undergoing testing showed the largest age group were individuals between 31 to 50 years (age range 14 – 78 years old), with a relatively balanced gender distribution of 51.3% female and 48.7% male patients. Electronic patient records were used to obtain data pertaining to the test indications, presenting complaints, imaging findings and diagnoses. We identified that 78.9% (n = 60) of all HLA-B27 test requests did not aid in leading to a diagnosis and were therefore ultimately classified as low value. For 28% of the HLA-B27 test requests, the clinical indication was either unclear or not documented in the patient records. 20% were ordered to investigate suspected inflammatory arthritis, yet further diagnostic workup appeared limited. Only 18% of the patients underwent MRI imaging. In the majority of these cases an MRI lumbar spine and sacroiliac joints was performed. Among these, Romanus lesions were identified in just one instance. None of the MRI imaging demonstrated the presence of sacroiliitis. Only a single case, representing 1.3% of the total was deemed to be clearly helpful in leading to a new diagnosis. In this singular case a diagnosis of JIA / ankylosing spondylitis made by the paediatric team due to borderline imaging findings. Key learning points HLA-B27 testing is widely used in the diagnostic workup of ankylosing spondylitis (AS), but its clinical significance is often misunderstood. While the presence of HLA-B27 can be associated with AS, a positive result does not confirm the diagnosis, and a negative result does not exclude it. This nuance is important because reliance on HLA-B27 status alone can lead to misdiagnosis, misdirected investigations or treatments. Our analysis of the HLA-B27 testing practices at ESTH Trust reveals that a substantial proportion of tests have poor diagnostic yield, as they are frequently ordered without appropriate clinical justification. This pattern of usage does not conform to established guidelines such as NICE [NG65] in the UK or Choosing Wisely Canada, both of which recommend targeted testing based on specific clinical criteria. Overuse of HLA-B27 testing can result in unnecessary anxiety for patients who have a positive result. The absence of careful counselling regarding this genetic test in our cohort of patients, often results in patients arriving to clinic with the belief that they have the diagnosis because of a positive HLA-B27 test alone. Improper usage of HLA-B27 testing also has significant financial implications. We estimate that reducing unnecessary requests could result in annual savings of roughly £27,000 for HLA B27 tests alone in our organisation. Extrapolating this cost saving across our ICB (Integrated Care Board), which has 4 NHS Trusts, an anticipated saving of £108,000 annually could be made. To optimise laboratory resources and enhance patient care, we recommend a multifaceted approach: implementing evidence-based protocols for test ordering, providing ongoing education to clinicians about appropriate indications for HLA-B27 testing, and instituting stricter criteria for ordering the test. These measures will align practice with best-practice guidelines, reduce low impact testing, and ultimately improve clinical outcomes.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".