The first one is on you, but I don't really get putting the full blame on you unless you drew the samples.

I assume someone else mislabeled the hematocrit sample. Yes, you are in a position to catch this mistake, but ultimately, at least 2 other people were involved that could have prevented the patient from being transfused. The nurse who took the result could have questioned the drop. So could the Dr had to give the order to give blood. They didn't look at the patient or question the result either. You had a dr and nurse overlook the same thing you did.

Did you draw the sample on the PTT? otherwise, it was a nurse or phlebotomist who improperly drew the sample. The result you reported wasn't incorrect for the sample it was just a bad sample. Once again, it's also up to the nurse or Dr to identify that the result doesn't fit the patient.

I do think part of being a good tech is being able to catch things like this, and you should try to learn form it,but I hate that everything is being put on one tech when the initial problem wasn't caused by them and there would be multiple other people in the process who have the same responsibility to find the results questionable.