False myths and legends in laboratory diagnostics.

Remarkable advances in understanding human biology in health and disease, propelled by technological innovations, have contributed to an increase in the number and quality of diagnostic tests. This evolving scenario has been accompanied by the proliferation of false myths and legends in laboratory diagnostics, consuming valuable human and economic resources and jeopardizing the clinical reasoning. The aim of this article is to provide a synthetic overview about some paradigmatic examples of false beliefs in laboratory diagnostics involving activated partial thromboplastin time (APTT), cardiospecific troponins, ischemia modified albumin (IMA), D-dimer, prostate specific antigen (PSA), dibucaine number, Bence Jones protein (BJP), lipoprotein(a), neutrophil gelatinase-associated lipocalin (NGAL), potassium and reference ranges. Although the suggestive cases described in this article are not intended to be comprehensive, we hope that their description may help remove some mysticisms in laboratory diagnostics.