Laboratory diagnosis of thyroid disease: a clinician’s perspective

Abstract

Thyroid disease is common and readily treatable, but key aspects of diagnosis and management remain controversial. For example, serum thyrotropin measurement is central to the diagnosis of thyroid dysfunction, but the laboratory reference range remains contentious, despite a wealth of population-based normative data. The health impact of mild thyroid dysfunction (particularly in elderly people) is unclear, making it difficult to establish reference ranges for thyroid function tests based on clinical outcomes, as is done for other analytes such as cholesterol. Pregnant women are increasingly screened for thyroid disease, but many laboratories do not apply pregnancy-specific reference ranges, leading to misclassification, with the potential for mismanagement. Difficulties in management can be compounded by poor communication between clinical pathology staff and clinicians, and <i>vice versa</i>. This presentation will review controversial aspects of the diagnosis and management of thyroid disease, with an emphasis on the often inadequate evidence base which guides clinical decision-making, and the shaky foundations which underlie the ever more numerous guidelines and position statements on thyroid disease.