AIM: To study an association between clinical and morphological evidence and the 
serum and daily urinary levels of cystatin C (CysC) and neutrophil 
gelatinase-associated lipocalin (NGAL) in patients with primary 
glomerulopathies.
SUBJECTS AND METHODS: The investigation included 104 patients; morphological 
examination showed minimal change disease in 15 (14.4%) patients, focal 
segmental glomerulosclerosis in 24 (23.1%), membrane nephropathy in 32 (30.8%), 
and IgA nephropathy (mesangioproliferative glomerulonephritis) in 33 (31.7%). 
The investigators analyzed the clinical type of nephropathy, performed 
conventional laboratory and instrumental examinations, and determined the level 
of CysC (by immunoturbodimetry) and NGAL (by enzyme immunoassay) in the serum 
and daily urine taken before kidney biopsy. The degree of glomerulosclerosis, 
tubulointerstititial sclerosis, and tubular atrophy was semiquantitatively 
estimated.
RESULTS: Urinary CysC and NGAL excretion correlated with the degree of 
glomerulosclerosis and proteinuria and the reduced glomerular filtration rate 
(GFR) regardless of the method of its determination. The urinary level of NGAL 
positively correlated with the degree of tubular atrophy. The GFR value 
determined from serum CysC and creatinine levels more precisely reflected the 
degree of glomerulosclerosis.
CONCLUSION: The tubulointerstitial compartment in primary glomerulopathies 
should be determined not only by morphological changes, but also by tubular 
function parameters by estimating the urinary excretion of biomarkers. The 
urinary content of CysC reflects tubular epithelial dysfunction whereas that of 
NGAL also characterizes tubular atrophy. To estimate the degree of 
glomerulosclerosis, it is more preferable to use the GFR calculated from the 
blood concentrations of CysC and creatinine, by keeping in mind clinical 
findings (using Chronic Kidney Disease Epidemiology Collaboration formula, 
2012).