ABSTRACT
Early identification of PNH, a rare life-threatening disease is essential to ensure appropriate management via the UK PNH service. Since testing for PNH is expensive (75.97 per test), we set out to assess the suitability of PNH requests against guidelines with the aim to feedback to colleagues and reduce unnecessary testing. To determine whether PNH requests at UHNM were in line with criteria in British Society for Haematology (BSH) guidelines. All patients over 18 years of age who had PNH testing for the first time and those who had repeat testing for monitoring between 01/04/2019 and 31/03/2020 were included. Patients were selected from electronic records of PNH sample receipt to laboratories. Hospital records were reviewed for clinical details and investigation Results. 82 requests including 79 individual patients were audited. 57% were male and 43% were female. Median age was 56 years. 97.6% of PNH tests were requested by a haematologist whilst only 2.5% requests were done by non-haematology clinicians. 52.4% requests were in keeping with BSH recommendations, whilst 47.6% tests did not meet criteria for testing. All patients tested outside of guideline recommendations were negative. Of the reasonable requests, only 23.3% (10) were positive. Of the PNH positive patients, 8 patients were known to have a PNH clone with aplastic anaemia;one patient had a hypoplastic bone marrow and a known PNH clone whilst only one patient with cytopenia had a new positivity for PNH. The frequency monitoring for aplastic anaemia and a PNH clone was 100% concordant with BSH recommendations. With appropriate testing, only one new patient was identified. Our audit has limitations. We have not been able to assess whether any patients outside of those monitored for PNH in aplastic anaemia have been overlooked for testing. Also, the time period includes the COVID-19 pandemic so our findings may not reflect usual practice. New BSH guidelines for thrombophilia testing were published in 2022 and recommend testing for PNH in patients with thrombosis at unusual sites and abnormal haematological parameters and for patients with arterial thrombosis and abnormal blood parameters. This will likely limit excess tests although the sensitivity and specificity of such an approach has not been formally evaluated. In a finite health system, it is our responsibility to rationalise investigations. The cost of a year's testing was 6229.54 and that of inappropriate testing was 2962.83. As a department, we could, therefore, save 2962.83.