The acceptable range for thawing plasma and cryo is 30 to 37 C. We have a note in our SOP that states, "A temperature <38 C is considered acceptable for the required 30 to 37 C range required by Standards for thawing plasma and cryo." We can't find the source of this statement . We've looked in Standards, Technical Manual, all the obvious places. Has anyone seen this statement in print anywhere?

"Less than 38 C" implies that the temp could be 37.99999 C, but probably means that the decimal point on the digital thermometer is immaterial -- and it probably is! We set our waterbath at 36.0 C to make sure the digital display doesn't exceed 37.0 C.

I had the pleasure of speaking to a Metrologist years ago, who all but laughed at my assertion that the thermometers I was using were accurate because they were NBS-certified or -calibrated. I wish I still had the article he gave to me that delved heavily into the uncertainty of measurements.

I'm afraid in my many years in the business I have never seen that statement. The 30 - 37oC is the only thing I remember ever seeing in reference to thawing plasma products. It's just a guess but I suspect that some one from the forgotten past in your facility thought it sounded good and kept them from over reacting if the thawing bath ever dropped below 30oC or (heaven forbid) went up to 37.1oC.

It will be interesting if someone really can find a reference for it. Personally I kind of like it for the very reasons I have mentioned above.