Replying to Robyn P. 23/07/2025 - 10:57
Great question!
Lovely o hear from you. I hope you are well and enjoying the course.
For Diff-Quik or similar Romanowsky-type stains, here’s what’s generally recommended to maintain stain quality and avoid cross-contamination:
Recommended Frequency of Changing Stain Solutions:
Every 100–150 slides is a common general rule of thumb.
More frequently if you’re processing dirty or infectious samples, like abscesses, ear swabs, or cytologies from ulcerated masses. These contaminate the fixative and stain solutions much more quickly.
If you notice stain precipitate, contamination, or colour shift, that’s a red flag the stains need changing — even if you haven’t hit the “slide limit.”
At least monthly is a good minimum for routine use in low-throughput clinics, even if the stain still looks OK.
Best Practice:
Use separate stain sets for potentially contaminated samples (like ear or faecal swabs) versus clean cytologies (like lymph nodes or FNA of internal organs).
Always close the lids tightly and avoid topping up old solutions — replace fully.
Clean and dry the Coplin jars before refilling.
Document your stain change dates somewhere visible in the lab to help everyone stay on the same page.
I hope that helps! Have a lovely weekend.
Scott 🙂
