Establishing equations to evaluate 24 hour urine protein excretion using routine urinalysis.

ABSTRACT

AIM: It is necessary to screen people at high risk for proteinuria with an economical, reliable and convenient method. The aim of this study is to establish a new approach to predict 24 h urine protein (24 h UP) by routine laboratory assays. METHODS: Five centres were included and a total of 4211 hospitalized patients were enrolled. All samples were assayed for dipstick protein (DSP), specific gravity (SG), 24 h UP and serum albumin (ALB) simultaneously. 4211 patients were randomly divided into two groups for establishing and testing the equations. Equations were built by multiple log-linear regressions. RESULTS: (i) DSP is significantly correlated to 24 h UP in a logarithmic pattern; (ii) SG interprets 24 h UP for specific DSP; (iii) Equation 1 = 0.203 × 10(dummy-variable F) × [100 (SG-1)](-0.470) ; and (iv) Equation 2 = 13.366 × 10(dummy-variable F) × [100 (SG-1)](-0.547) × [ALB (g/L)](-1.130) The dummy-variable F had a point-to-point accordance to DSP (detailed in text). CONCLUSION: Combination of DSP and SG can interpret normal-range proteinuria well, and helped by ALB, their interpretation for macro proteinuria is much improved. It is dependable and economical for routine urinalysis to evaluate pathological proteinuria by equation.