Short-term experimental hypercalciuria does not produce hematuria in normal subjects

Hypercalciuria in the absence of urolithiasis has been considered to be a cause of asymptomatic hematuria. No mechanism for this association has been demonstrated. In an effort to establish the specificity of this association, we induced hypercalciuria in 10 healthy subjects by oral administration of 1,25(OH)2 vitamin D for 10 days. This protocol reproducibly produced markedly increased urinary calcium excretion (mean calcium:creatinine ratio 0.5). Despite this, no subject developed hematuria as seen by dipstick urinalysis or by alteration in erythrocyte Addis counts (mean counts 1.02 x 10(6)/12 h before vitamin D and 0.84 x 10(6)/12 h after 10 days of therapy). This study provides no evidence that short-term hypercalciuria alone produces hematuria in otherwise healthy individuals.