In patients with resistant hypertension (RH) we investigated the importance of 
urinary neutrophil gelatinase-associated lipocalin (uNGAL- a chemiluminescent 
microparticle immunoassay (CMIA) method became using (Abbott Diagnostics) for 
the measurement of NGAL in urine samples) and incidence of chronic kidney 
disease using the Modification of Diet in Renal Disease Study (MDRD) and Chronic 
Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in estimating 
glomerular filtration rate (eGFR) based on standardised serum creatinine method 
traceable to isotope dilution mass spectrometry (IDMS) method. It would have 
been difficult to predict that levels of these biomarker would perform better 
organ damage than traditional measurements of kidney function such as 
standardised serum creatinine, MDRD, or CKD-EPI equations in special population 
such as RH. Serum creatinine concentrations were measured in 50 patients 
(24M:26F from RH Registar in Clinical Hospital Merkur) by the kinetic Jaffe 
method. There were no significant differences between the GFR values derived by 
MDRD and CKD-EPI equations in the group of patients with RH. 62% of patients 
have eGFR > 60 mL/minl/1.73 m2, while a 38% of patients have eGFR < 60 
mL/min/1.73 m2. The measurement of NGAL in urine samples of 40 patients with RH 
showed no difference and seems to be of no use in further determination of renal 
impairement. Higher value of uNGAL in some resistant hypertension patients could 
have link in the repair stage after AKI and would reveal pathways that could 
link AKI and CKD.