Ludmia Taibi, Bénédicte Bénéteau-Burnat, Michel Vaubourdolle, Bruno Baudin
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引用次数: 1
Abstract
Determination of angiotensin-converting enzyme (ACE) activity in cerebrospinal fluid (CSF) can help for establishing the diagnosis of neurosarcoidosis. We investigated the performance characteristics of two assays for ACE determination in 57 CSF, radiometry with [glycine-1-14C] benzoyl-L-histidyl-L-leucine and spectrophotometry with furylacryloyl-phenylalanyl-L-glycyl-L-glycine (FAPGG) as substrates. We compared both kinetic assays to an ELISA specific for human ACE. Within run and between run imprecisions were 14-17% for radiometry, 6-19% for spectrophotometry and 5-8% for ELISA. The limit of detection was 0.04 U/L for radiometry, 1.0 U/L for spectrophotometry and 0.156 μg/L for ELISA. The limit of quantification was 0.06 U/L for radiometry, 1.5 U/L for spectrophotometry, but not known for ELISA. The domain for quantification was 0.06-4.0 U/L for radiometry, 1.5-24 U/L for spectrophotometry and 0.156-10 μg/L for ELISA. Deming regression and Bland-Altman plots show good correlations between the three assays, but with high slopes, because both kinetic assays use different substrates and ELISA measures ACE molecule but not activity. Radiometry was more sensitive than spectrophotometry, which has a limit of detection above most pathological levels. ELISA could be an alternative to radiometry but only after complete evaluation, determination of normal values and assessment of its clinical value. We claim for standardization of ACE determination as well as in serum as in other biological fluids, in particular CSF.
期刊介绍:
Multidisciplinary information with direct relevance to everyday practice
Annales de Biologie Clinique, the official journal of the French Society of Clinical Biology (SFBC), supports biologists in areas including continuing education, laboratory accreditation and technique validation.
With original articles, abstracts and accounts of everyday practice, the journal provides details of advances in knowledge, techniques and equipment, as well as a forum for discussion open to the entire community.