Design, validation and performance of aspartate aminotransferase- and lactate dehydrogenase-reporting algorithms for haemolysed specimens including correction within quality specifications

Abstract

Background In vitro haemolysis is a major operational challenge for medical laboratories. A new experimental design was used to investigate under what conditions algorithms could be designed to report either quantitative or qualitative aspartate aminotransferase and lactate dehydrogenase results outside the manufacturer’s haemolysis specifications. Quantitative corrections were required to meet prespecified quality specifications. Methods Twenty-five patient samples were used to design reporting algorithms and another 41 patient samples were used to validate the algorithms. Aspartate aminotransferase, lactate dehydrogenase and haemolysis index were determined using a Cobas 6000 analyser (Roche diagnostics, Mannheim, Germany). Correction factors were determined, and the accuracy of the correction was investigated. Reporting algorithms were designed based on (i) the manufacturer’s cut-off for the haemolysis index, (ii) corrections within the total allowable error specification and (iii) qualitative reporting based on obtained results. The impact of the reporting algorithms was retrospectively determined by recalculating six months of aspartate aminotransferase and lactate dehydrogenase results. Results No correction for aspartate aminotransferase/lactate dehydrogenase was possible for results below the upper reference interval limit, while results equal to or greater than the upper reference interval limit could, up to mild haemolysis, be corrected within the total error criterion. All samples generated from the validated patient cohort fulfilled the set criteria. The algorithms allowed reporting 88.5% and 85.9% of otherwise unreported aspartate aminotransferase and lactate dehydrogenase results, respectively. Conclusions An approach is presented that allows to generate and validate reporting algorithms for aspartate aminotransferase and lactate dehydrogenase compatible with prespecified quality specifications. The designed algorithms resulted in a significant reduction of otherwise unreported aspartate aminotransferase and lactate dehydrogenase results.

Lung cancer tumor marker analysis: A clinical laboratory perspective

“…Two tumor markers, NSE and lactate dehydrogenase (LDH), are among the analytes most sensitive to in vitro hemolysis. Even minimal erythrocyte lysis can falsely increase the concentrations of these tumor markers, as they are released from the erythrocytes [5,6]. The other pre-analytical processes that potentially affect the accuracy and reliability of lung cancer tumor markers are sample management, transport, and storage.…”