Applicabilità del valore della variazione di riferimento per l'interpretazione di dati ripetuti. L'esempio della troponina I plasmatica nella diagnosi di infarto miocardico acuto

Background. The aim of many recent studies was the evaluation of reference change value (RCV) by means of different calculation methods nevertheless the effectiveness and applicability of RCV to routine diagnostics is not yet established. The purpose of present study was to show the possible diagnostic use of RCV for the interpretation of repeated data of troponin I (cTnI) in patients with acute myocardial infarction (AMI). Methods. We retrospectively evaluated 40 patients admitted to the emergency cardiology department; they were classified by expert medical staff that compared the increase of cTnI both with decisional cut off for AMI and RCV. The effectiveness of RCV was verified with a cohort study evaluating the patients with and without RCV. We used a test of Chi square for the statistical analysis. Results. Statistical analysis demonstrated the non-significance between the two groups suggesting the lack of added value of RCV calculated using a commercial assay (p=0.51). However, the RCV, calculated with the present method, simplifies the interpretation of repeated data and introduces a methodological novelty in term of the analytical variability used in the formula estimated by a profile of imprecision. Conclusions. The results of cohort study suggest an applicability of RCV in a small number of patients with elevation of cTnI.