Abstract
Follow-up studies of findings obtained during a short programme of biochemical screening conducted on 1,041 patients attending their general practitioners in January 1967 showed that this yielded 64 results that led to a change in diagnosis or method of treatment. These results were obtained in 57 patients (5.5% of patients screened), whereas only 15 abnormal results would have been revealed on 14 of the 1,041 patients if the tests performed had been restricted to those requested on the basis of clinical features. Hence a screening programme can make an important contribution to the recognition of otherwise unsuspected disease.