We report 12 patients belonging to five different families in whom persiste
nt isolated microhematuria was associated with hypercalciuria and/or hyperu
ricosurla, Four patients had episodes of gross hematuria, three patients ha
d passed renal stones, and a history of nephrolithiasis was obtained in fou
r of the families (80%), Calcium oxalate and uric acid crystals were common
ly observed in the urine sediments. Urinary erythrocytes had a normal appea
rance on phase-microscopic examination. Reduction of calciuria and uricosur
ia by thiazide diuretics, allopurinol, forced fluid intake, and dietetic me
asures led to a persistent normalization of urine sediment with complete di
sappearance of hematuria. Determination of calcium and uric acid urinary ex
cretions should be included in the study of familiar hematuria. (C) 2000 by
the National Kidney Foundation, inc.