[Histonet] Temperature Monitoring Questions

[Melanie Walker]

Dear Histonetters,

We are considering overhauling our temperature monitoring SOP for GLP preclinical veterinary histology laboratory and would like to give ourselves some leeway with minor / short term temperature excursions. I recently attended a workshop wherein it was mentioned that you could include acceptable excursions into your SOPs. Currently we are writing a lot of deviation reports for minor excursions.  I would love some opinions on temperature excursions in a GLP (not GMP/CAP) histology lab environment. We do not store temperature dependent study materials such as test articles / drugs / fresh or frozen tissues, etc., only staining reagents.

Is it acceptable to state that since stain reagents are regularly removed from the refrigerated environment during staining use for up to an 8 hour shift, that excursions up to room temperature for a period of less than 8 hours are acceptable? How about if we include the language that each staining run will be completed with a known positive control to demonstrate continued effectiveness of the staining reagents? What about excursions below standard fridge temp of 2-8C? Anything above freezing OK? Does the use of a known positive control with each run effectively negate the need to report excursions? Would the same logic apply to IHC reagents that are stored at fridge temperatures? Similarly if a -20 freezer is still within freezing temp would that be acceptable - right now we have a +/- 3C range on the -20 storage but we are really just trying to avoid freeze / thaw cycles right? Going down to -12 C for a couple hours shouldn't be detrimental...

Similarly, we are monitoring the room temperature of the histology laboratory but have noted previously that sometimes in the summer the afterhours temps can sometimes be OOS (the AC can only work so hard!) - since work is not being performed during this time there is no detrimental effect on sectioning / embedding quality and reagents are tested upon each use with known controls, can we include some language to that effect to reduce the number of deviations reports for OOS temps?

Is it required to have a NIST certified thermometer / calibrate against such if we are not manufacturing nor storing drugs  / test articles / etc.? Can we use  another acceptable accredited calibration standard (i.e., ISO/IEC 17025 accredited calibration laboratory)? Is this necessary for our purposes?

Also, we recently acquired data logging thermometers with alarm capability - the procedure would move from daily tech review of each thermometer to monthly management review of the data (along with of course addressing any OOS situation that sets off the alarms in the moment). We would log the monthly review as well as retain the data printouts for facility records. Any concerns with this approach?  I think one concern is that if they set the alarm to go off below the stated acceptable range they will need to produce a deviation however if they set it above so it notifies them before an OOS has occurred they are dealing with alarm situations when the temp is still within range... how do others handle this?

Any additional advice/ feedback regarding monitoring fridge / freezer / lab space temps as pertains to histology staining / processing would be much appreciated!
Sorry for the million questions! Thanks in advance!