Clinical Significance of Renal Biopsy in Adults with Asymptomatic Microscopic Hematuria

Kim, Hyung Jong; Choi, Hoon Young; Kim, Dong Ki; Kim, Hyun Jin; Chang, Jae Hyun; Kim, Hyun Wook; Choi, Kyu Hun; Lee, Ho Yung; Han, Dae Suk; Kang, Shin Wook

Abstract

BACKGROUND
Hematuria is most frequently detected on routine urinalysis and the prevalence of hematuria in adults has been reported to range from 5 to 10 percent. Hematuria can originate from any site along the urinary tract and whether gross or microscopic, may be a sign of serious underlying disease including malignancy. The literature agrees that gross hematuria warrants a thorough diagnostic evaluation. By contrast, whether physicians should test for hematuria in asymptomatic patients remains at issue, and the role of renal biopsy in the investigation of this condition is still debated. The purpose of this study was to assess the clinical significance of renal biopsy in adults with asymptomatic microscopic hematuria on urinalysis. METHODS: From January 1993 to December, 2002, 119 patients (72 men, 47 women) with mean age 26.4 years (range 15 to 40 years), in whom renal biopsy was performed for evaluation of asymptomatic microscopic hematuria, were included. All patients were normotensive, with normal serum creatinine, sterile urine, and no abnormality on IVP and abdominal ultrasonography. RESULTS: In 119 patients, renal biopsy abnormalities were found in 100 patients (84.0%) whereas no histologic abnormality in 19 patients (16.0%). Histologic abnormalities included IgA nephropathy in 73 (61.3%), thin glomerular basement membrane disease in 12 patients (10.1%), minimal mesangiopathy in 7 (5.9%), and other glomerular diseases in 8 patients (6.7%). When the patients were divided into two groups based on the presence of proteinuria, 55 patients belonged to isolated hematuria group (H) and 64 patients to concomitant hematuria and proteinuria group (H+P). Histologic abnormalities were statistically more common in H+P group (62/64, 96.9%) compared to H group (38/55, 69.1%) (p<0.05). On the other hand, when the renal biopsy findings were analyzed according to the amount of hematuria (3-10/HPF vs. 10-20/HPF vs. many/HPF), there was no significant difference in the results of renal biopsy among the three groups. CONCLUSION: Eighty four percent of patients with asymptomatic microscopic hematuria had renal biopsy abnormalities. Therefore, renal biopsy should be performed in patients with asymptomatic microscopic hematuria, especially in patients with concomitant hematuria and proteinuria, if renal imaging is normal.