Angiotensin-converting enzyme in hypercalcaemic disorders.

. Serum angiotensin-converting enzyme (SACE) was elevated (mean ± S.D. 55.2±19.8 U/ml) in 11 patients with hypercalcaemia due to sarcoidosis, whereas it was within the normal limits (20.0±5.2 U/ml) in 23 patients with other hypercalcaemic conditions. Among these, 16 had primary hyperparathyroidism and a SACE level of 18.6±4.7 U/ml, significantly lower than in healthy controls (24.4±6.2 U/ml). In 7 patients with hypercalcaemia due to malignancies or prolonged immobilization SACE was 21.8±5.9 U/ml. A weakly positive correlation was found between SACE and S-calcium in hypercalcaemic sarcoidosis patients but not in the other patients or in a control group of 144 consecutive sarcoidosis patients. Sarcoidosis with hypercalcaemia seems to be associated with a very high prevalence of elevated SACE. Especially when sarcoidosis is suspected to be the cause of hypercalcaemia, SACE measurement may be useful as a rapid diagnostic guide.