An audit of the measurement and reporting of male testosterone levels in UK clinical biochemistry laboratories

Abstract

Introduction: A number of guidance documents have been published in recent years for the diagnosis and management of hypogonadism (HG). Laboratory practice has a major role in supporting guidelines with accurate and precise serum total testosterone (TT) methods and standardised pre- and post-analytical protocols. Our study investigated whether laboratory practice currently supports the management guidelines for HG.

Methods: An internet-based questionnaire survey of senior laboratory biochemists (UK/Republic of Ireland) was conducted (April-May 2018). Questions reflected sampling, laboratory practice, reference ranges and reporting of results. The results were analysed in conjunction with data obtained from the UK National External Quality Assurance Service (UK NEQAS) on testosterone assay performance.

Results: Analyses of 96 laboratory surveys returned the following: 74 laboratories stated that the optimal sampling time was communicated to users; 81 laboratories used immunoassays; 76 laboratories included reference ranges for adult men (31 had dual/multiple age-related intervals). Wide variability in lower/upper limits was evident in the common immunoassays; the majority of reference ranges were from manufacturers (50.0%) or historical (18.8%). Action limits based on TT levels were used by 64 laboratories, but 63 did not report a borderline range as suggested by the guidelines. Protocols for cascading tests based on TT were evident in 58 laboratories, with 50 laboratories offering estimated free testosterone; interpretative comments were provided by 67 laboratories, but no references were made to the management guidelines. Data from UK NEQAS demonstrated considerable variation in testosterone assay performance.

Conclusions: Our survey has highlighted inconsistencies that could lead to HG (and other conditions requiring measurement of TT) not being managed appropriately. The results from this survey and from UK NEQAS reinforce the requirement for action to be considered regarding the standardisation of testosterone assays and harmonisation of laboratory practice.