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Two dry-reagent systems evaluated for determinations of enzyme activities
J C Hafkenscheid1, J van der Ven-Jongekrijg
1Department of Internal Medicine, St. Radboud Ziekenhuis, Nijmegen, The Netherlands.
Clinical Chemistry
|January 1, 1988
Summary
This study compared two dry-chemistry systems, Kodak Ektachem and Boehringer Mannheim Reflotron, for enzyme activity measurements. Results showed significant discrepancies between the systems and routine methods, indicating dry-chemistry and wet-chemistry results are not interchangeable.
Area of Science:
- Clinical Chemistry
- Biomedical Diagnostics
- Laboratory Medicine
Background:
- Dry-chemistry analyzers offer potential advantages in speed and ease of use for clinical enzyme assays.
- Evaluating the accuracy and interconvertibility of different dry-chemistry systems against established methods is crucial for reliable patient diagnostics.
Purpose of the Study:
- To assess the performance of Kodak Ektachem DT60/DTSC and Boehringer Mannheim Reflotron analyzers for measuring six enzyme activities.
- To compare the results obtained from these dry-chemistry systems with a routine wet-chemistry method.
- To determine if results from dry-chemistry and wet-chemistry procedures are interconvertible for key enzyme analytes.
Main Methods:
- Enzyme activity concentrations for six enzymes were measured using Kodak Ektachem DT60/DTSC and Boehringer Mannheim Reflotron analyzers.
- Results were compared against a standard wet-chemistry procedure.
- Commercial test sera were assayed on both dry-chemistry and wet-chemistry systems to evaluate interconvertibility.
Main Results:
- Kodak Ektachem showed high coefficients of variation (CVs) for low concentrations of aspartate aminotransferase (AST) and alanine aminotransferase (ALT).
- Reflotron yielded lower AST and ALT values compared to Ektachem and wet-chemistry, attributed to the absence of pyridoxal 5 ahydroximate phosphate in its slides.
- Activity concentrations of gamma-glutamyltransferase (GGT) and creatine kinase (CK) measured by Ektachem showed poor agreement with the routine procedure, potentially due to overestimation by the Ektachem.
- Assays on commercial test sera indicated that results from dry-chemistry and routine procedures are not interconvertible.
Conclusions:
- The Kodak Ektachem and Boehringer Mannheim Reflotron dry-chemistry systems exhibit significant performance differences and limitations for specific enzyme assays.
- Discrepancies in enzyme activity measurements between dry-chemistry analyzers and conventional wet-chemistry methods highlight the lack of interconvertibility.
- Clinical laboratories should exercise caution when adopting dry-chemistry systems, as results may not be directly comparable to established wet-chemistry protocols, necessitating method-specific validation.