Dynamic testing in the diagnosis and follow-up of patients with acromegaly

Acromegaly is an important area of endocrinology which deserves careful biochemical assessment with growth hormone and IGF-I measurements. Growth hormone suppression during oral glucose tolerance and elevated IGF-I levels form the main diagnostic criteria before treatment has begun. After treatment growth hormone levels during oral glucose tolerance and IGF-I levels are assessed again. A significant proportion (about 30%) are disparate. Thus either having elevated growth hormone levels in the presence of a normal IGF-I or vice versa. Dynamic tests for the diagnosis and monitoring of acromegaly are really not helpful. Assays for growth hormone and IGF-I are changing and absolute levels must be treated with circumspection because of the different assays involved. It is essential for the practicing endocrinologist to know which assays are being used by his or her laboratory for the adequate interpretation of the figures that emanate from it.