The value and application of a multiphase screening programme of preoperative laboratory investigations on ENT patients is described and assessed. Appropriate laboratory investigation should be chosen. The methods of investigation should provide information about the patient's general condition, should identify disease which has escaped clinical assessment, which is not connected with the underlying disease, but which could severely handicap a patient undergoing surgery.

They are also designed to assist in the medical screening of the general population. The programme includes tests of organ function and of metabolism. The frequency of abnormal laboratory values (less than 2.5% at to longer end of the normal distribution curve or above 5% at the other) was 7.8% for blood sugar, 2.9% for serum creatinine, 4.5% for urea, 11.6% for uric acid in men and 4.8% in women, 9.8% for serum cholesterol, 2.9% for SGOT in men and 20.8% for triglycerides.