Automated determination of angiotensin-converting enzyme in serum

This is an adaptation of the Fujirebio "ACEcolor" kit for automated measurement of angiotensin-converting enzyme (EC 3.4.15.1) in serum with the Cobas Fara centrifugal analyzer. The linear range extends to an activity of 110 U/L. Results obtained by the present method and by the manual method were identical, and correlated closely (r = 0.983) with those by Cushman's modified method. The reference interval for 77 adult blood-bank donors was 9-25 U/L (mean 17, SD 4 U/L). Within-run and between-run CVs are 1.7 and 4.0%, respectively. The present method permits rapid, precise, and economical measurement of the enzyme and allows users of a Cobas Fara centrifugal analyzer to introduce a fully automated assay for angiotensin-converting enzyme into their clinical laboratory.