Challenges of Endocrine Function Testing in Resource Poor Settings

The endocrine system controls the flow of information between cells and tissues, governed by complex regulatory mechanisms (1). Hormones exert widespread influences on various metabolic processes which ensure regulatory, morphogenic and integrative function (2). Signs and symptoms of endocrine disorders span the entire clinical spectrum. Manifestations of endocrine diseases are frequently due to non‐endocrine or unknown causes such as fatigue, malaise, weakness, headache, anorexia, depression, weight gain or loss. Endocrine diseases are therefore, easily recognisable in their extreme forms and arriving at clear diagnosis can sometimes be difficult (1). Early diagnosis and management of endocrine diseases are essential and can be achieved by the combination of targeted endocrine testing, imaging, careful history, physical examination and sound clinical judgement (1,3). Adequate knowledge and understanding of basic science and principles of endocrinology are important tools for the enhancement of efficiency and accuracy‐goals of endocrine function testing. The perfect strategy (3) for targeted endocrine investigation would achieve the ideals of reaching specific diagnosis in the shortest time, with minimum inconvenience and cost on the patient. It is generally accepted that agreed strategies done in stages and could vary with location are needed for maximum efficiency which include: • Stage 1: The initial clinical investigations • Stage 2: Selection of initial laboratory tests • Stage 3: Interpretation of initial laboratory tests • Stage 4: Second line investigations STRATEGIES (3) The initial clinical investigations comprise of detailed clinical history and physical examination. The selection of appropriate initial laboratory tests will be determined by the outcome of the initial clinical investigations. Interpretation of initial laboratory tests requires acquaintance with reference intervals appropriate to specific laboratories and methods since immunoassays are method dependent. Second line investigations could be determined from results of the initial investigations and should either confirm or clarify an endocrine basis or monitor response to treatment. They are of a wide range and most conveniently, may be recorded in series of algorithms because many patients will not require further endocrine tests. A wide range of hormone assays is thus needed. Various analytical techniques are used for measuring hormones including bioassay, receptor assay and immunoassays. Bioassays and radioreceptor assays were used for quantitation of biological activity in the 1950s. Since 1960,