Discriminant functions in differential diagnosis of hypercalcemic patients

Using readily available biochemical assays of plasma and urine constituents, we have defined discriminant functions useful as a guide to the differential diagnosis of patients with hypercalcemia. The decreasing rank order of contribution of the variables to the discriminant functions was as follows: plasma albumin, plasma phosphate, plasma chloride, log10 (calcium excretion per liter of glomerular filtrate), and log10 (plasma gamma-glutamyltransferase). Discriminant functions have been defined for patients with values for plasma creatinine above and below 185 mumol/L, and for practical conditions in which plasma and urine samples, or plasma samples only, are available.