[Clinical relevance of 25-hydroxyvitamin D estimation in plasma (author's transl)].

Plasma concentrations of 25-hydroxyvitamin D (25-OH-D) were determined in 40 healthy persons and in patients with primary osteoporosis (n = 43), primary hyperparathyroidism (n = 19), intestinal osteopathy (n = 13), and after small intestine bypass operations (n = 8). The control group showed physiologic seasonal variations which must be taken into account in the individual case. Whereas there were no deviations from the normal in patients with osteoporosis, significantly lower values were obtained in the other disease groups. Estimation of 25-OH-D in plasma represents a valuable contribution for the diagnosis of generalized osteopathies and for the differential diagnosis of hypercalcaemia. In addition, the effects of vitamin D treatment may be objectively assessed. Overdosage and intoxication may be recognized in time.