SUMMARYSince bone markers may reflect different aspects of bone disorders and cell function, and osteolytic and osteoblastic activities may be individually or concomitantly altered, determination of more than one marker type is generally appropriate. Also, the individual markers of a particular type do not necessarily show parallelism. For example, in osteomalacia from vitamin D deficiency, bone‐specific alkaline phosphatase may be grossly elevated because of enhanced osteoblastic activity, whereas the vitamin D dependent osteocalcin may be decreased. With the exception of measurement of the bone enzymes, bone‐specific alkaline phosphatase and tartrate‐resistant acid phosphatase, bone marker measurements require complex and expensive immunoassays. As a general rule, the simple enzyme measurements can precede other investigation in most bone disorders. Bone‐specific alkaline phosphatase measurement alone is generally adequate for the investigation of osteomalacia, Paget's disease and hyperparathyroidism but should be combined with measurement of tartrate‐resistant acid phosphatase in suspected metastatic disease, and in multiple myeloma. Determination of both enzymes together may also be of value in the investigation of osteoporosis but in this disorder added benefit may be obtained by the addition of other bone markers, particularly urine deoxypyridinoline and possibly serum collagen telopeptide.

SUMMARYSimple biochemical investigations serve to identify diabetes, can assist in its management, and facilitate the early recognition of complications. This review outlines some of the applications of various relevant test procedures.

SUMMARYBiochemical test abnormality can indicate chronic alcohol abuse with good clinical sensitivity and specificity. Serum gamma glutamyltransferase and carbohydrate‐deficient transferrin are the tests most frequently abnormal.

SUMMARYDisturbed adrenal function may present in various ways. Here are outlined some of the functions of the adrenals and the clinical effects of adrenal disorder, followed by a more detailed consideration of the application of laboratory tests to the identification of adrenocortical hypo‐ and hyperfunction.

SUMMARYThe porphyrias are inherited disorders of haem synthesis and must be considered in the differential diagnosis of numerous disorders.