A 32 year old man presents following the passage of dark red urine with blood clots, soon after his regular morning jog. He also complains of a feeling of fullness in the left flank.

There is no history of trauma, or of other urinary symptoms. Nor is there a family history of bleeding disorders.

His smoking history amounts to 5 pack years. He only drinks socially, and does not use recreational drugs.

When a urine sample is requested, he complains of difficulty voiding, and can only partially empty his bladder. Urinalysis demonstrates a field full of red blood cells, with no cell casts or pus cells.

A full blood count is significant for a hemoglobin level of 10.1 g/dL. A renal function assay is within normal parameters.