“To be a fecal matter donor in the first place you already need to have a superior gut. At OpenBiome, the sole U.S. stool bank that provides samples for most of the transplants, requirements include the obvious: no family history of inflammatory bowel disease or colon cancer, no frequent stomach issues like bloating, constipation, or diarrhea, and no recent antibiotic use. But they also screen for autoimmune and mental health conditions like depression, anxiety, asthma, and allergies, which have all been potentially linked to the microbiome.
“Our donors, they go through a pretty rigorous screening process; overall the pass rate is just under 3 percent,” says Majdi Osman, the clinical program director at OpenBiome. “We always joke here that it's harder to become a stool donor at OpenBiome than it is to get into Harvard.”
Right now, beyond the rigorous health screen, scientists aren’t exactly sure what they’re looking for in a donor, which makes identifying super stool difficult. No one strain of bacteria ensures a healthy gut. In fact, entire families of bacteria are present in one seemingly healthy person and absent in another. The only thing that healthy guts seem to all have in common is diversity—the more bacterial strains, the better.”