My 10 year old's urine shows +1 occult blood. is this concerning and what could it be? he's had 2 done and shows same results.

Hematuria: Since he has no other symptoms he may have benign hematuria. If his father had a similar problem it would be called familial benign hematuria, and as the name implies it is a benign condition.

Needs follow-up: Microscopic hematuria unassociated with proteinuria needs further follow-up. Persistent microscopic hematuria over 18 months warrants kidney biopsy.