Reference ranges and diagnostic thresholds of laboratory markers of cardiac damage and dysfunction in a population of apparently healthy black Africans

Background: Due to the increasing migration flows mostly concerning Western countries, the problem of reference ranges and cut-off values is a living matter. In particular, the influence of ethnic origin on traditional and novel biochemical markers of cardiac damage, including cardiac troponin T (cTnT), ischemia modified albumin (IMA) and N-terminal prohormone brain natriuretic peptide (NT-proBNP), has not been investigated, to the best of our knowledge. Methods: CTnT, NT-proBNP and IMA were assayed by a Modular System in 34 apparently healthy black Africans originating mainly from Central Africa and in 34 apparently healthy white, non-immigrant Italians, matched for age and sex. Results: All the subjects investigated displayed cTnT values < 0.01 ng/mL. Black Africans displayed significantly increased concentrations of serum IMA (107 vs. 92 kU/L, p < 0.0001), but not of NT-proBNP (4.9 vs. 3.8 pmol/L, p = 0.4), as compared to the white, non-immigrant Italians. Conclusions: The results of our investigation indicate that the reference ranges and the thresholds values of IMA, but not those of cTnT and NT-proBNP, may be different according to the ethnic origin of the population. Therefore, although the current decisional thresholds of both cTnT and NT-proBNP may be appropriate for diagnosing cardiac damage and dysfunction in the black African population, that of IMA may require a revision toward higher values.