Hemocytometer Controls

[Darren 18]

Hello all. Am I the only one that doesn't get hemocytometer controls. We run a liquid control when we do them, but it really seems that manual counts should be an issue of competency with a validated hemocytometer, not a qc issue. Even if you get a manufactured disposable hemocytometer with multiple counting areas you're only running qc on two areas that you don't even use for counting the patients. So it seems that QC is assessing the tech performance rather than the hemocytometer. Particularly if using an old glass one with the same coverslip over and over.

[JasonS 24]

I've never entirely understood their purpose either.

We have a commercial control which we use with our classic re-usable hemocytometers. We use a homemade stain for our counting.

Yes, if a tech tends to count somewhat higher/lower than their peers they risk failing QC. This would also include variables for doing the setup such as overfilling the chamber, poorly cleaned chamber, or poor mixing(Since we use a stain). 

You could argue that since the QC is done once a day, that a competent tech would pass the QC, and later on a less competent tech would set up a body fluid and do it with poor accuracy(They're not doing QC so this can't be assessed). In my case you could say the QC proves the stain is working properly though in my experience our stain can be used for months and have no stability issue. It would also help prove that the hemocytometer they used is in satisfactory condition(We would use 2 hemocytometers for daily QC and we have 10 in use, so we might not QC each individual one every week since there is no plan for rotating them).

So we are kind of proving that some of the systematic parts of the fluid counts are working properly(but not all of them) and proving that at least one of the techs is counting properly. 

 

[JCarpenter 10]

I have also thought this is odd.  So I use a urine control since we are only assessing if the techs can count and fill a chamber properly.  We do have our QC set up so that each tech counting must do QC it is not just once per shift.  If the same tech is doing another body fluid they do not have to run QC again but if it is a different tech then they must do their own QC.