HPV primary screening and abnormal screen follow-up

Test types

There are several types of tests used in the primary screening and triage process. The four most common are: HPV partial genotyping, liquid-based cytology, P16-Ki67 immunostaining, and methylation.

HPV partial genotyping

This test identifies if HPV is present and which type. It is mainly used for primary screening but can also be used for triage. Partial genotyping of HPV 16/18 allows for identification of the highest risk strains of the virus. Australia uses this type of test.

Liquid-based cytology

This test detects abnormal or potentially abnormal cervical cells. It is used for triage in HPV primary screening programs. Cytology has the largest volume of historic follow-up data but cannot be used for triage with patient-collected samples. Australia, Finland, the United Kingdom, and the Netherlands all use cytology to triage screening participants who test positive for HPV.

P16-Ki67 immunostaining

This test measures a cellular protein related to the activity of HPV oncogene E7. It is used mainly for triage in HPV primary screening programs and improves risk stratification. It may more accurately distinguish between transient HPV infections and those more likely to progress to cancer. P16-Ki67 immunostaining provides high specificity when combined with HPV 16/18 genotyping but is not yet cost effective.

Methylation

This is a molecular test related to the development of malignancies. It is used for triage in HPV primary screening programs and can be performed on patient-collected samples, as intact cervical cells are not required. It can be used with HPV 16/18 genotyping as an alternative to HPV 16/18 genotyping with cytology.