First, the part that outranks everything else on this page: blood in your urine — visible, or found on a test — always deserves medical assessment in its own right, regardless of anything this check suggests. Most causes are common ones (infections, stones), and a doctor should look. That stands alone.
Why it's in a pelvic-vein check at all: in Nutcracker syndrome, the compressed renal vein raises pressure inside the left kidney until small amounts of blood cross into the urine — typically painless, sometimes only microscopic, sometimes appearing after exercise. Combined with left flank pain and pelvic congestion symptoms, it completes a recognisable trio that many clinicians have simply never been taught to assemble — urology checks the kidney, finds it healthy, and the vein level goes unexamined.
If you answered yes: see a doctor about the blood itself, and if the standard work-up comes back clear while the rest of your pattern fits, "could this be renal vein compression — Nutcracker syndrome?" is the question that connects the dots. Your check summary lays that pattern out for exactly this conversation.