Sammanfattning
Background. A highly sensitive troponin T analysis became available in Norway in 2009. The Norwegian Society of Medical Biochemistry believed that a national strategy for implementation of the analysis would ensure a more coherent practice for diagnosing acute myocardial infarction (AMI).
Material and methods. 70 laboratories were requested to identify (in a questionnaire) the type of assay used, routines for reporting results of analyses, internal quality control programmes (IQA) and local cut-off values for making the diagnosis AMI.
Results. 62 laboratories responded and 57 of these analyzed troponins; 60 % used troponin T and 40 % troponin I. 82 % of laboratories were familiar with the decision limit used for diagnosing AMI at their hospital; 43 % of troponin T laboratories used the cut-off recommended by the Norwegian Society of Cardiology (0.03 µg/l) to diagnose AMI. For the two most used troponin I methods (16 laboratories) eight different cut-off values were reported. 24 % (troponin T) and 35 % (troponin I) of laboratories performed IQA at a concentration similar or lower than the local decision limit used when diagnosing AMI. 73 % (troponin T) and 54 % (troponin I) of laboratories used the lower limit of quantification as the lower cut-off value for reportable results.
Interpretation. In Norwegian hospitals, users of the same methods for analysis of troponin have different routines for interpreting, IQA and reporting of results. Patient diagnoses may therefore vary according to the hospital used. The Norwegian Society of Medical Biochemistry has developed recommendations for implementation of troponin analyses in Norwegian laboratories.