The HPV test is primarily used as an alternative to the pap smear for cervical cancer screening today. It helps to detect the presence of high risk types of HPV viruses that are associated with the development of cervical cancer.
Studies have shown that compared with pap cytology, HPV testing is more sensitive for identifying women who have CIN2+ (precancer of cervix) though it has a slightly lower specificity (false positives) compared with cytology .
Hence HPV testing in women younger than 30 years would have even lower specificity and not be useful in these women. In Singapore, the HPV test is recommended only for women above the age of 30 years for cervical cancer screening according to the Singapore national guidelines. On the other hand, pap smear cytology is recommended from 25 to 29 years of age.
If the HPV test positive, further evaluation is performed depending on the genotype of virus detected. If type 16 and 18 are detected, it would be recommended that the woman goes for a colposcopy evaluation as the risk of developing high grade precancer is above 10% in next 2 years.
Colposcopy is a diagnostic tool performed by trained gynaecologists to look for any areas of abnormality on the cervix or vagina which may have resulted in the abnormal screening test.
On the other hand, if other types of HPV (other than 16 or 18) are detected, a pap smear cytology is recommended or performed to check for the presence of abnormal cells. If abnormal cells are present, the woman would need to have a colposcopic evaluation. If it is normal, then a repeat HPV test is recommended a year later to check for clearance of the viral infection.
