I had a question from the Micro lab manager about how do people handle cultures when there is nothing left in the bag? The transfusion reaction either occurred after the unit was already transfused or they gave the rest of the unit anyway. She said that they have added saline that is supposedly sterile but when the culture is positive it is hard to say with certainty that it was really the unit and not the way that the culture was performed.

Thanks,

Colleen

We've never had a problem here with insufficient volume. Usually between the tag lines and what is left in the giving set there is enough. But where I worked previously they didn't insist on either the giving set or any fluids that had been injected during the transfusion and that did cause problems.

I have seen people doing the 'one arm centrifuge' though and shaking all the blood to the end of the bag by swinging it about lol

http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/08vol34/34s1/34s1-eng.php

Try this link from the Public Health Agency of Canada - they recommend adding aseptically tryticase soy broth or sterile saline to the bag, mix well, reaspirate and culture. I think one can always question whether the bag was actually contaminated or whether the bugs came from the culturing process (especially when the bugs could be the same either way); we can only be as careful as we can culturing. A common QA benchmark is to keep your false positive rate for regular blood cultures below 3%, so maybe we should be expecting a small # of false positives anyway.