I must respectfully disagree with those that consider calibrations of your microtome and stainer times "rubbish". I don't understand the reluctance of many of my histology colleagues to GLP compliance and to Quality Assurance. Firstly without QA there is no such thing as GLP compliance. I understand that sometimes QA people do not know much about histotechnique. At the same time they do know quite a bit about documentation and compliance. Most QA people are willing to listen, but again that should be a two way street.
In the example of the microtome, Pamela's solution is perfect. If the person doing the PM uses calibrated and and traceable equipment and provides you with documentation, you're set. What you have shown QA and the FDA (when they show up) is that your microtome operates according to the manufacturer's specifications. That's it. We all know that the thickness of a section can vary (thick-thin), but a GLP based calibration only addresses the operating condition of your equipment. A "trained" histotechnician would be able to spot any problems in sectioning thickness. Yes?
As far as stainer times are concerned, use a calibrated and traceable timer to check that the times match. Do it once, document it and you're done. Have QA check off on it and everybody is happy.
I would suggest any lab that does a fair amount of GLP work do an IQ, OQ, PQ on their system. I know it can be a pain, but more and more CLIENTS are asking for it, not just QA.
I understand that compliance can be more work. It is more work. What I don't understand is the reluctance of some to avoid making sure that their lab is in compliance with FDA or CAP. If your loved one had a biopsy come through a lab, how would you feel about someone using outdated reagents on that sample or using poorly maintained equipment?
Twin Cities Histology
>Date: Fri, 31 Oct 2008 10:20:36 -0400
>From: "Pamela Marcum"
>Subject: RE: [Histonet] Microtome calibration
>To: , "'Dr. med. Frauke Neff'"
>Content-Type: text/plain; charset="iso-8859-1"
>We have a GLP person who is not familiar with Histology at all. We have had
>to educate her about these issues and may other things. Calibration finally
>came down to having a PM on the units every year. After she understood all
>the things we do with a section during the cutting phase and pick up that
>would alter a true measurement.
>We also do MMA sections on the microtome and even those are next to
>impossible to measure due to some stretching of the section during pick up
>and drying. Oh Yes, the drying of the slides really put her in a tail spin
>as this was just not allowing the sections to stay the same as when they
>were picked up.
>Sometimes a long talk and demonstration is the only way to make the point
>that we are not standardized like clinical chemistry etc.
>Pamela A Marcum
>University of Pennsylvania
>School of Veterinary Medicine
>Comparative Orthopedic Laboratory (CORL)
>382 W Street Rd
>Kennett Square PA 19438
>[mailto:email@example.com] On Behalf Of Rene J Buesa
>Sent: Friday, October 31, 2008 10:08 AM
>To: Dr. med. Frauke Neff
>Subject: Re: [Histonet] Microtome calibration
>That calibration is ussually done by measuring the advance mechanism of the
>block holder and how many µm the block moves towards the blade, but that is
>--- On Fri, 10/31/08, Dr. med. Frauke Neff
>From: Dr. med. Frauke Neff
>Subject: Re: [Histonet] Microtome calibration
>Cc: firstname.lastname@example.org, email@example.com
>Date: Friday, October 31, 2008, 9:41 AM
>Dear Dr. Girish,
>I agree with rene, if the qualitiy of the cuts is fine it doesn't matter if
> are 1µm or 2.3µm thick.
>But I'm highly interested in how your GLP auditors want to calibrate the
>thickness of the section cuts. Are you supposed to measure the slides after
>cutting?! Before or after stretching in the water bath?! If they have a
>protocol how to do this I would be happy if they can share it with us.
>Quoting Rene J Buesa :
>> Dr. Girish:
>> BOTH "requirements" are rubbish invented by bureaucrats with
>lots of time in
>> their hands and trying to appear concerned and knowledgeable.
>> Thickness is not necessary as long as the section is diagnostically useful
>> if some quantitative method as to the intensity is done in which case
>> thickness = amount of matter, and would influence the outcome of the
>> quantitative process.
>> Timing the tissue processor is also totally irrelevant because it does not
>> really matter a few minutes each way during a processing protocol. More
>> important would be to keep a record of the fixation time that is the only
>> step really critical in tissue processing.
>> René J.
>> --- On Fri, 10/31/08, firstname.lastname@example.org wrote:
>> From: email@example.com
>> Subject: [Histonet] Microtome calibration
>> To: firstname.lastname@example.org
>> Date: Friday, October 31, 2008, 2:49 AM
>> Dear all
>> Is anyone practising microtome calibration for thickness of sections cut?
>> Our GLP auditors are frequently asking for it.
>> They also suggest that automatic tissue processor time in each reagent
>> should be calibrated.
>> any comments
>> Dr Girish
Histonet mailing list