I got this info from one of those embryo-related forums that can't be linked here. Quite a few options cleared the basic chemical checks for preservative percentage and acidity level but never went through any bacteria or toxin screening in the report. Their preservative power and acidity lined up fine, yet nothing can be said about germ or fever agent safety based on what's out there. One version passed the preservative, acidity, and bacteria tests but came back too high on the toxin reading, above the allowed threshold. That shows even versions that look chemically solid might carry a toxin hazard. By comparison, a few others came in with far too little preservative, didn't pass bacteria checks, and carried very high toxin counts. A couple more had preservative levels that fell outside the acceptable range. One had roughly the right preservative amount but an acidity reading that was far too high. Another had zero preservative at all, making it identical to plain sterile water even though it was sold as the preserved type, which points to a labeling or mixing error. In the end I went with the hospital version.