Type and crossmatch

People that get frequent blood transfusions can develop other antibodies that can effect compatibility. Not major issues, like A vs B, but less common antibodies.

It's because each unit needs to be physically crossmatched, and the sample is only good for 72 hours. Of course computer assisted crossmatching is becoming more widespread, but you still need a new sample every 3 days to ensure there is no change in the patient's antibody status.

Hope that helps- I rarely give blood so someone more experienced might have more insight.

I understand that aspect of it sure, but let's say for example no blood was given in that 72 hour window of needing another type and crossmatch and then the patient for whatever needed blood after that 72 hour window from the first sample drawn. If no blood products were given that would cause the patient to have come into contact with other antibodies then I don't understand why it needs to be rechecked at that point, why did it expire? Thanks!

Blood is perishable. They can only retest for a finite period of time. The retest is not only due to potential antibody development but also sample degradation.

If the patient does not receive any transfusions the crossmatch should be good for 30 days, if the patient is transfused then the crossmatch needs to be repeated for additional transfusions more than 72 hours after the first transfusion.

I understand that aspect of it sure, but let's say for example no blood was given in that 72 hour window of needing another type and crossmatch and then the patient for whatever needed blood after that 72 hour window from the first sample drawn. If no blood products were given that would cause the patient to have come into contact with other antibodies then I don't understand why it needs to be rechecked at that point, why did it expire? Thanks!

I am pretty certain most places rely on serum cross matching and not computer assisted. So the sample needs to be redrawn to allow for crossmatching.