Objectives To reveal etiologies of persistent isolated hematuria (PIH) through ultrastructural pathological examination

to disclose clinicopathological correlation in cases with PIH

and to summarize appropriate management of patients with PIH. Methods we retrospectively studied 155 PIH patients receiving renal biopsy between January

2003 and December

2008 in Peking Union Medical College Hospital. All the clinical data and follow-up result were analyzed. Results All subjects included 38 children and 117 adults

with mean age of 11.38±3.25 years for children and 35.17±8.44 years for adults. Thin basement membrane nephropathy (TBMN) was the most common pathology (55.3% of children and 49.6% of adults)

followed by IgA nephropathy (18.4% of children and 32.5% of adults

mainly grade 2-3) and mesangial proliferative glomerulonephritis (MsPGN) without IgA deposition (13.2% of children and 12.8% of adults). Besides

Alport syndrome (2.6% of children) and membrane nephropathy (2.6% of children and 0.9% of adults) were demonstrated as other causes of PIH. Elevated mean arteral pressure or protein excretion rate

as well as episodic macrohematuria

indicated higher risk for MsPGN rather than TBMN. On the other hand

severity of microhematuria was irrelevant to pathological types of PIH. Totally

86 patients were followed up and 37 cases therein stayed on track for long term (mean duration 41.11?28.92 months

range 8-113 months). Most cases had benign clinical course except 3 cases with TBMN

5 cases with IgA nephropathy

1 case with MsPGN (without IgA deposition)

and 1 case with Alport syndrome

who developed hypertension or proteinuria. All of them were administered timely intervention. Conclusions Close follow-up should be required as the primary management for PIH. Equally important is careful monitoring for early identification of undesirable predictors; while renal biopsy and other timely intervention are warranted if there is hypertension

significant proteinuria or renal impairment.