SAT359 The Biochemical Investigation of PCOS: A UK Wide Survey of Laboratory Practice

Disclosure: J. Hawley: None. R. Marrington: None. F. MacKenzie: None. J. Adaway: None. A. Taylor: None. W. Arlt: None. B.G. Keevil: None. Background Polycystic ovary syndrome (PCOS) is a heterogenous condition that affects approximately 12% of females. The diagnosis can be complex and biochemistry tests are routinely relied upon to help identify hyperandrogenaemia and to exclude other conditions. However, although national and international guidelines advocate the use biochemistry tests, little information is provided as to which tests should be used and which other endocrinopathies should be excluded. Objectives To gather information about what tests UK laboratories routinely use to investigate PCOS, what reference ranges are applied, and which other conditions are routinely excluded. Design A national survey consisting of 32 questions was compiled by clinical scientists and clinicians. This was circulated to NHS clinical laboratories via UK NEQAS and The British Endocrine Society with online access available between June – December 2021. Supplementary to the survey, UK NEQAS distributed three cases for interpretation to complement their steroid hormone scheme. Results The survey attracted responses from 81 participants. Of these, 90% identified that testosterone would be included in an initial screen with only 50% using it in combination with SHBG to provide a free androgen index. Of the conditions that are not routinely excluded; 74% would not add TSH to investigate hypothyroidism and 84% would not consider adding 17OHP to exclude late onset CAH. Testosterone analysis is commonly performed by immunoassay in the UK with only 12% of respondents using LC-MS/MS. Reference ranges for testosterone varied with the most commonly used being a manufacturer derived <1.7 nmol/L (<49 ng/dL) and the highest reported being a luteal upper limit of 6.0 nmol/L (173 ng/dL). Several participants (64%) identified that they would send high testosterones to an LC-MS/MS laboratory for confirmation, the concentration at which this occurred ranged from >1.2 nmol/L (>35 ng/dL) to >5 nmol/L (144 ng/dL). Androstenedione was only included by 16% of participants in the initial screen with the majority using LC-MS/MS for its measurement and the upper limit of normal ranging from 4.6 to 14.3 nmol/L (132 to 410 ng/dL). The results from the clinical interpretation provided varied responses. Conclusions There is significant variation across the UK in the investigation of PCOS. This is apparent in which tests are offered by biochemistry laboratories, what reference ranges are used and, as a direct consequence of these, what interpretation is applied. This potentially further complicates the investigation and diagnosis of PCOS and represents an inequality across the healthcare system. There is a requirement for clear guidance on what tests should be used to investigate PCOS. Presentation Date: Saturday, June 17, 2023