Cervical Cytology (Pap Test)

What it does

Cervical Cytology reads a whole scanned Pap slide, liquid-based (ThinPrep or SurePath) or conventional. A screening slide holds tens of thousands of cells, and the abnormal ones can be a handful; the run searches the whole slide and brings the most abnormal cells to the top.

The result gives specimen adequacy, the Bethesda 2014 interpretation (NILM, ASC-US, LSIL, ASC-H, HSIL, squamous cell carcinoma or atypical glandular cells), notes on organisms and reactive changes, and a gallery of the top-ranked abnormal cells, each linked to its position on the slide. Guidance takes an HPV co-test result into account when one is supplied.

Intended use

Decision support for primary screening and rescreening: the cytotechnologist or cytopathologist reviews the gallery first and the slide second. Glandular lesions, rare abnormal cells on a crowded slide and poorly focused preparations are the known difficulties.

Who it is for

Cytotechnologists, cytopathologists and screening laboratories, including small labs that lack a second screener. Developers use the run to add Bethesda-coded results and cell galleries to a cytology LIS or screening registry.

Accepted input

• One Pap slide per run, scanned as a whole-slide image: DICOM VL Whole Slide Microscopy Image or a vendor file (SVS, NDPI, MRXS, iSyntax, SCN, BIF, CZI, OME-TIFF).
• Preparations: ThinPrep and SurePath liquid-based slides and conventional smears.

Requirements

Requirement	Why
Pap stain recorded in the slide metadata or upload	Routes the slide to cytology rather than histology reading
Pixel spacing in µm/px	Cell and nuclear size are compared in micrometres
Sharp focus across the cell layer (z-stack where available)	Cell groups are three-dimensional; blurred groups are listed in quality flags
Preparation type (ThinPrep, SurePath, conventional)	Cell distribution and background differ between preparations

Optional context

The HPV test result and the clinical setting (routine screening or follow-up of a prior abnormality) can be passed in clinical_context; the guidance uses them.

The result

Section	Content
Bethesda category	Adequacy, Bethesda 2014 category, organisms and reactive changes, and the ranked abnormal-cell gallery with slide coordinates
Draft report	Opt-in (options.report): an English narrative that interprets the result for the reader (findings, impression, limitations); every number is checked against the findings

The gallery and the category arrive in one JSON result; each gallery cell keeps its coordinates so a viewer can jump to it on the slide.

Standards

• Reporting: The Bethesda System for Reporting Cervical Cytology, 2014 (Bethesda 2014): specimen adequacy, general categorisation and interpretation.
• DICOM: abnormal cells as Microscopy Bulk Simple Annotations, the category in SR TID 1500, the report as Encapsulated PDF.
• Interoperability: FHIR R4 DiagnosticReport and Observation, SNOMED CT coding.

Bethesda categories

The run reports these Bethesda 2014 interpretations: negative for intraepithelial lesion or malignancy (NILM); the squamous categories ASC-US, LSIL, ASC-H, HSIL and squamous cell carcinoma; and atypical glandular cells (AGC). Adequacy (satisfactory or unsatisfactory for evaluation) is reported before the interpretation.