Bethesda System

Bethesda System in Cervical Vaginal Cytology

Criteria defining specimen adequacy

•    Glass slides must be whole (ie. not broken and unable to be repaired)
•    Clinical information on the patient must be available
•    Slides must have an appropriate label/reference number that is referable to a patient’s identifiers
•    Squamous cells (intermediate squamous cells/metaplastic squamous cells) must be well-preserved and visible—less than 75% of these cells can be obscured by blood, inflammation, air drying, thick areas, poor fixation, contaminants
•    Conventional smears from a cervical sample must contain between 8000-12000 intermediate/metaplastic squamous cells
•    Slides from Thinprep/liquid-based preparations must contain more than 5000 intermediate/metaplastic squamous cells
•    At least 10 columnar/metaplastic cells (from the cervical transitional zone) should be seen—if not, then this must be mentioned in the report
•    Should an epithelial abnormality be seen, it should be reported regardless of specimen adequacy

Bethesda System categories included as squamous epithelial cell abnormalities

•    Atypical squamous cells (of uncertain significance, cannot rule out HSIL—ASC-US, ASC-H)
•    Low grade squamous intraepithelial lesion (LSIL)
•    High grade squmous intraepithelial lesion (HSIL)
•    Invasive squamous cell carcinoma

Terminology

•    Approach to management differs between each of these lesions