Biochemical investigation of hypertension.

Underlying causes of hypertension are found in less than 5% of cases but they are frequently surgically remediable. Elementary biochemical tests are usually sufficient to exclude most renal and endocrine causes of hypertension. However, young patients with very high blood pressures merit more detailed investigation in specialized centres. As coexistent hyperlipidaemia or glucose intolerance substantially worsen the prognosis for a given level of blood pressure, these two risk factors are worth assessing in all hypertensive patients. Their presence may also alter the choice of antihypertensive drug therapy. About 25% of the population have raised blood pressure at first screening and about 10% are in need of drug therapy, so this represents an appreciable load on biochemical laboratories. Most patients, however, need only a single biochemical profile on one occasion, and should be exclusively managed in general practice.