[Correlation between urinary sediment spectra and pathological patterns of renal biopsies]

To investigate the clinical value of urinary sediment analysis, a non-invasive diagnostic means, in the evaluation of pathological patterns of renal diseases.

A total of 1 140 pairs of matched renal biopsies and fresh fasting morning urine specimens were collected from hospitalized patients in Peking University First Hospital. Their urinary sediments were examined with phase-contrast microscopy; the 24 h urine proteins were measured. Based on urinary sediment features combined with urine protein amount, the spectra of the urine sediments were classified into four types, Type I: hematuria-dominant, with multiple cells and casts; Type II: proteinuria-dominant, with hyaline or fine-granular casts but scanty cells; Type III: renal tubular epithelial cell(RTEC)-dominant, minor proteinuria; Type IV: non-specificurine sediments,minor proteinuria. According to the pathological lesions detected in renal biopsies, the renal diseases were classified into three patterns: proliferative glomerulopathy(P-GP), non-proliferative glomerulopathy (NP-GP) and tubulointerstitial nephropathy(TIN). The urinary sediment spectra of different pathological patterns and the correlation between urinary sediment types and pathological patterns were analyzed. Statistical analyses were performed using kappa test, and χ(2) test, and significance was accepted at P<0.05.

(1) Of the 840 cases of matched urine samples and renal biopsies, 419 cases were diagnosed with P-GP; 375 cases with NP-GP; 46 cases with TIN respectively. (2) The spectra of urine sediments were associated with pathological patterns of the renal biopsies, and 84.0% of the patients with P-GP manifested type I urine sediments; 93.1% of the patients with NP-GP had type II urine sediments; 67.4% of the patients with TIN had type III urine sediments. (3) The correlation between the urinary sediment types and renal pathological patterns was validated in an additional 300 matched samples. The positive predictive values of urinary sediment spectra in predicting renal pathological lesions were 84.8% for typeI to P-GP, 86.0% for type II to NP-GP and 73.7% for type III to TIN, respectively.

As a non-invasive diagnostic means, the urinary sediment analysis is valuable in the evaluation of pathological patterns of renal diseases.