ABSTRACT
Introduction: Human papillomavirus (HPV) testing is used as a means of triaging cervico-vaginalsmears with low grade squamous abnormalities or as part of co-testing with cytology. While HPVtesting has a high sensitivity, it has a low specificity in detecting cervical intraepithelial neoplasiagrade 2 and above (CIN 2+) leading to unnecessary colposcopy referrals. We investigate the accuracyof the p16/Ki-67 dual immunocytochemical stain in determining the presence of CIN 2+ lesions onhistology and its potential as a superior biomarker for triage. Methods: Liquid based cervico-vaginalcytology specimens with squamous abnormalities and corresponding histology from 97 women withsubsequent colposcopy and biopsy were included. The specimens were then subjected to the dual stainand Roche Cobas 4800 multiplex real time PCR HPV DNA testing. The sensitivity and specificity ofthe dual stain and HPV testing were calculated using CIN 2+ on histology as a reference standard.Results: The sensitivity and specificity of the dual stain in detecting histology proven CIN 2+ was93.7% and 76.5% while HPV testing was 85.7% and 14.7% respectively. Of the 44 women withASCUS or LSIL on cytology, the dual stain also reduced the number of unnecessary colposcopyreferrals from 27 to 7 when used as a triage marker compared to HPV testing. Conclusion: p16/Ki-67dual stain was more sensitive and specific than HPV testing in determining the presence of CIN 2+on histology. It could triage low grade cervico-vaginal specimens more effectively and potentiallyhelp women avoid unnecessary colposcopies. Future studies are needed to further evaluate its rolein cervical cancer screening programmes.