A short guideline on chronic kidney disease for medical laboratory practice

Abstract

Chronic kidney disease (CKD) is asymptomatic in the early stage. Kidney function might be lost 90\% when the symptoms are overt. However, in case of early detection, progression of the disease can be prevented or delayed. If not detected it results in end stage renal disease. Therefore, the level of awareness about CKD should be increased. The role of medical laboratory is utmost important for the diagnosis and staging of CKD. In this paper, the main tasks of the laboratory specialists are described and the outlines are as follows. Creatinine assays should be traceable to internationally recognised reference materials and methods, specifically isotope dilution mass spectrometry. When reporting the creatinine result, eGFR should also be reported in adult (> 18 years) population. A warning expression should be included in the report form if eGFR result is <60 mL/min/1.73 m(2). eGFR values should be expressed quantitatively up to 90 mL/min/1.73 m(2) by CKD-EPI equation. Above 90 mL/min/1.73 m(2), eGFR values can be expressed quantitatively or >90 mL/min/1.73 m2. eGFR equations of the adult population should not be used for pediatric population. Different equations utilizing also patient height should be used. The enzymatic creatinine assay should be preferred. eGFR based on cystatin C can be used for confirmation in the pediatric population. Cystatin C measurements, at least when eGFR based on creatinine is not reliable and for confirmation should be encouraged. Proteinuria or albuminuria values should be measured in spot samples and reported in proportion to creatinine.