How prevalent are clotting disorders and how do they affect candidacy for hair transplants?

I'm sorry to hear about your disappointing FUE transplant results. It's good that you and your surgeon are trying to understand what might have contributed to the lower-than-expected density. Excessive bleeding during the procedure, even if not extreme, can sometimes impact the grafts' ability to "take." Bleeding can interfere with the precise placement of grafts and may create an environment where grafts have difficulty settling and establishing blood flow, which is crucial for their survival.
While you haven’t been diagnosed with a clotting disorder, it's worth considering whether any underlying factors, like medications, supplements, or even a mild clotting irregularity, could have played a role. Bleeding disorders, if present, can certainly affect the outcome of hair transplants. Grafts rely on proper blood supply to thrive, and if there is prolonged bleeding or clotting difficulties, it can reduce the likelihood of graft survival.
That said, achieving success is still possible, even if a bleeding issue is present, but it may require a more tailored approach. Pre-operative assessments, including blood work to check for clotting factors, and adjusting surgical techniques or medications might help improve outcomes for future procedures. If you’re considering a revision, it would be important to discuss all these aspects.