BETA-TRACE PROTEIN AS A MARKER OF RENAL DYSFUNCTION IN PATIENTS WITH CHRONIC KIDNEY DISEASE: COMPARISON WITH OTHER RENAL MARKERS

Beta-trace protein (BTP), also known as prostaglandin D synthase, is a low-molecular-mass protein which belongs to the lipocalin protein family. It was found to be increased in the serum of patients with renal diseases. The aim of this study was to compare the clinical usefulness of serum levels of beta-trace protein for the detection of renal dysfunction in patients with chronic kidney disease (CKD) with levels of other renal markers: creatinine, cystatin C and beta(2)-microglobulin (B2M). The study included 134 patients with a wide range of renal dysfunction that encompassed all five CKD stages. Obtained data showed that beta-trace protein highly correlated (Spearman test) with creatinine (r = 0.890), cystatin C (r = 0.904) and B2M (r = 0.933) and its levels in serum significantly increased from CKD stage 1 to 5. Furthermore, the values of glomerular filtration rate (GFR) estimated from a BTP-based formula significantly correlated with GFR calculated from creatinine-based and cystatin C-based formulas. ROC analyses showed that BTP had similar diagnostic accuracy for detection of reduced renal function in CKD stages as other renal markers, for estimated GFRs of < 30, < 60 and < 90 mL/min/1.73 m(2). The areas under the ROC curves (AUC) for BIT; for these GFR limits, were from 0.983 to 0.917 and they were not significantly different from AUCs for other renal markers. The results of this study showed that BTP may be a useful and reliable serum marker for identifying the magnitude of renal dysfunction in patients with CKD and may have its place beside serum cystatin C and creatinine as an alternative endogenous GFR marker.