PPV of an HSIL cervical cytology result in China's largest CAP-certified laboratory

Cervical cancer remains a major health problem in China, where no uniform national standards for cervical cytology quality control exist. This study extends previously reported findings on cervical cytology performance in China's largest independent laboratory to have achieved accreditation under the international Laboratory Accreditation Program of the College of American Pathologists.

A retrospective study identified high-grade squamous intraepithelial lesion (HSIL) cervical cytology reports between 2007 and 2013 from the Cytology Laboratory, Guangzhou Kingmed Diagnostics. Four liquid-based cytology (LBC) preparations were used in 73% of cases and conventional Papanicolaou tests (CPT) in 27%. Follow-up histopathologic diagnoses after HSIL reports were identified in the laboratory database. The positive predictive value for laboratory HSIL cytology results was determined for follow-up histopathologic diagnoses of cervical intraepithelial neoplasia 2 or worse (CIN2+), a recognized international quality control monitor.

Of 1,804,108 cervical cytology reports, 11,929 HSIL reports (0.66%) were identified. The LBC HSIL rate was 0.79%, which was higher than the CPT HSIL rate of 0.33% (P < 0.001). Follow-up CIN2+ histopathologic diagnoses within 6 months after HSIL were identified in 1994 of 2414 patients (82.6%), including 1860 of 2246 LBC HSIL (82.8%) and 134 of 168 CPT HSIL (79.8%). Cervical cancers were diagnosed on follow-up in 244 of 2414 HSIL cases (10.1%).

The positive predictive value of HSIL cervical cytology results for follow-up histopathologic CIN2+ was within currently recognized benchmark ranges for cytology laboratories. The high rate of cervical cancer diagnoses likely reflects the largely unscreened population. The College of American Pathologists Laboratory Accreditation Program provided quality standards not otherwise available in many international settings.