Further experience with discriminant functions in differential diagnosis of hypercalcaemia.

Further experience has been obtained in the use of discriminant functions in the differential diagnosis of hypercalcaemia from the study of 140 new patients. The discriminant functions described in an earlier paper were derived from the results for plasma inorganic phosphate, alkaline phosphatase, chloride, bicarbonate and urea obtained from hypercalcaemic patients on admission to hospital. They indicated the correct diagnosis in ninety-two of 103 new hypercalcaemic patients (89·3%) admitted to University College Hospital and in thirty-one of thirty-seven hypercalcaemic patients at two other hospitals. Revised discriminant functions have been calculated including the erythrocyte sedimentation rate as a sixth variable. These revised functions have led to some improvement in diagnostic accuracy. The correct diagnosis was indicated in ninety-three of ninety-eight patients (94·9%) at University College Hospital and in thirty-three of the thirty-seven patients at the two other hospitals.