Principle of specimen preparation
To harvest as many viable cells from a specimen for an accurate Cytological assessment.
Accurate interpretation of cellular material is dependent on the following factors:
Types of non-gynaecological (general) Cytology specimens:
Fixation of Cytology Specimens
The main objective of fixation in cytology is to maintain the morphologic characteristics of the cell in as perfect as possible condition.
Cytology specimen should be smeared on the slide in a thin, even layer and immediately fixed in 95% alcohol or spray fixative. Immediate fixation of cellular material is an essential step for accurate cytological interpretation.
Equal volume of 50% alcohol is added to most fluids for fixation purposes and if delay in transportation is expected.
(50% dilution is made up by mixing equal volumes of 95 – 100% alcohol and distilled water)
If slides prepared at peripheral labs, describe the specimen type,(precise site of origin), macroscopic appearance, volume of the specimen, colour, clot present and the number of slides received and/or prepared.
Handling of specimens
Large quantity fluid: Let the specimen stand, this will cause the cells to settle at the bottom. Decant the supernatant carefully, not disturbing the sediment and extract the sediment with a pipette and prepare.
Small insignificant quantity (<0.5 ml) of fluid: Add saline and Cytospin. If the sample can’t be processed the clinician must be informed and comment logged onto Meditech.
When more than one sample is received from the same site, slides must be preparedfrom each sample.
When more than one sample is received from different sites, slides must be labelled accordingly.
Centrifugation: 1900 RPM for 10Min
Cytospin: 1000RPM for 10 Min.
cells, placing them on a labelled slide Go back in again, this time taking up cells from the bottom of the button or fluid that is there.
Reagents: Serum, thrombin.