Human retinol-binding protein: its relationship to renal function in renal diseases

Human Retinol-binding protein (RBP) was measured in serum and urine of 30 healthy volunteers and 66 renal disease patients with varying degrees of renal insufficiency in order to establish its clinical relevance in evaluating renal function. 24-hour creatinine clearance (Ccr) was used to assess renal dysfunction in all cases, and the serum RBP related to Ccr. There was a good correlation between serum RBP and creatinine (r = 0.80, n = 96, p less than 0.001) and, on logarithmic scale, between serum RBP and Ccr(r = 0.77, n = 80, P less than 0.001). Serum RBP was more sensitive in detecting early changes in glomerular filtration than serum creatinine and it is suggested that RBP may be useful in predicting glomerular filtration rate without the need for a 24 hour or time urine collection. Urinary excretion levels of RBP may also be useful in monitoring renal tubular function. It is concluded that RBP is useful in assessing renal function for the purposes of diagnosis and monitoring the course of progression of renal disease.