Specimen Collection Guideline

Cytology

• Performed on fine needle aspirates (FNA), fluids, scrapings, and imprints.
• We recommend using slides with one end frosted, on which sample identification data can be written in with a pencil, as pen and felt tipped markers will wash off in fixative during staining. Label the sample clearly with the patient name, date of collection, and sample location. Always use a pencil when labelling as ink will be washed off during staining.
• Avoid submitting slides in the same packaging with formalin-fixed samples as exposure to formalin can render cytology slides unreadable.
• Cytology cannot be done on swabs submitted in transport media.
• Body fluids (which includes abdominal, thoracic, pericardial, joints, and CSF) are best submitted in both EDTA and sterile tubes/containers. The EDTA preserves the cytology and prevents clotting to allow cell counts and protein estimates required for a full fluid analysis. The sterile tube/container may allow other procedures eg. culture, some biochemistry. However if there is insufficient volume available (as may be the case especially with CSF and joint fluid), then an EDTA sample is preferred (or at least a smeared slide preparation made from a small amount of the fluid).
• Other fluids are best submitted in EDTA as cytology is required. However if culture is also required, a separate sample of the fluid must be submitted in a sterile container.
• For FNA samples, it is strongly recommended that slides be forwarded from 2-3 separate aspirations taken from the lesion, from various locations within the sample, if size allows. This will increase the likelihood of a diagnosis. FNA samples that results in thick clumps on the slide do not typically have a monolayer of cells that is required for diagnosis. Visible clumps of cells should be spread over the surface of the slide by placing another slide at 90° to the first slide and smearing the clumps out with light pressure.

CityU VDL fees apply to cytology examinations whether the slides contain diagnostic material or not. We recommend that submitters prepare at least 3 slides of aspirates, stain and examine one of them at the clinic to ensure that diagnostic material is present before submitting all slides (stained and unstained) to the laboratory.