NPL Test Slides Query

[Colette WilloughbyModerator]

The following query was received by a Norac Member:

I have a bit of an enquiry for you that you may also wish to circulate to members of the NORAC group with regard to HSE test slides. I am currently on my third batch of slides received from my supplier (no surprise – JS Holdings). I have so far returned 12 slides to them in total, as when I have checked them prior to issue with testing equipment, I have found them to perform inadequately. All have come with the green coloured calibration certificates from HSL stating that Band 5 and partial Band 6 are visible. I can only see Band 4 as I would expect to see Band 5, none of Band 5, and you can forget about being able to see any of Band 6. This has been the case on all 12 slides returned. I have questioned whether the slides received are Mark II or Mark III, as discussed within HSG 248, as my findings reflect what I should find with those described as a Mark III slide which is issued with a red certificate. I have been assured this is not the case. What doesn’t help this is that there does not seem to be any consistency with the calibration certificates issued by HSL. After looking through historical calibration certificates I seem to have a mixture of some stating slides as being Mark II and some stating Mark III.

 

I have sent e-mails to HSL and included ULO Optics (manufacturer), and only received a defensive reply from HSL accepting no blame even though they have provided the calibration. I was told to chase this with my supplier (JS Holdings), who receive the calibrated slides from ULO Optics, put them into a JS Holdings labelled plastic case and sell them on. Not exactly a process that strikes me as capable of having an impact upon the suitability of a test slide.

I have tried these Test slides on a number of our Phase Contrast Microscopes (including Motic, Meiji Techno and Nikon) and the findings are the same on all of them. I have asked colleagues, including my Technical Manager and Quality Manager, as well as some of our analytical staff, to assess them in case it was my ageing and faltering eye sight, and again findings were the same. I have even assessed some of our current test slides on the same microscopes and on those the expected test bands are visible. I also took the liberty of asking our external microscope servicing engineer who happened to be at our head office during the time we had the first batch of test slides, to have a look at them. He also stated that they were not right.

What is interesting is that aside from ourselves and one small local laboratory that is run by a friend of mine, according to JS Holdings and HSL, we are the only laboratories to have reported such an issue. Interesting…

The response can be seen within the attached document.

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