We have a both a teperature chart and digttal readout on our refrigerators, platelet storage and freezers. Both readings are recorded daily and the SOPs state that not only must they be within range, but the difference between the 2 must be less than or equal to 2.  This is no problem for the fridges and platelet storage but the chart and digital readouts for the freezers sometimes differ by slightly more than 2.  With the wide temperature range (-18 t0 -30), I'd like to change the difference to 5 for just the freezers.  Would this violate any regulations?  I cant find anything...we are inspected by CAP, CAP-ISO, and FDA.  thanks 

I would suggest using a certified digital thermometer to check the accuracy of your digital readout - I would bet that's the accurate reading of the two (mine are always within 0.1-0.2oC of the reference thermometer). Then you should be able to adjust your temperature scribe (the weekly discs, right?) to exactly that temperature. Then you shouldn't have a problem. I like that better than making your tolerances bigger. The whole idea of the temperature scribe is to have a permanent record that your temperature is always within range, and there's no reason why this record should not be as accurate as possible. A 5oC acceptable difference is way too much.

Edited March 25, 201510 yr by Dr. Pepper