Objective: Non-invasive sampling of human genitals to identify high-risk individuals with subclinical oncogenic HPV infection remains a challenge. The study was designed to see if self-collected urine can be used as a simple, non-invasive sampling for screening HPV, particularly for screening/monitoring general population or young adolescents or infants, if they are to be immunized by HPV vaccines.
Method: Self-collected urine samples from 100 sexually unexposed college going girls and cervical scrapes from 104 normal healthy sexually active married women were used in this study. Additionally, a group of 55 women were recruited for collecting first urine and later scraped cervical cells to validate urine sampling by directly comparing HPV positivity between the two types of biological specimens. A dry 'paper smear' method for specimen collection and a simple single tube protocol was employed for PCR detection of HPV infection.
Results: Out of 100 sexually inexperienced college going girls, only 6 (6%) were positive for HPV infection as revealed by L1 consensus primer and 4 (4%) of them were positive for HPV 16 but none was found positive for HPV 18 DNA. Out of 104 sexually active married women who were cytologically reported as negative by Pap test, 11 (10.5%) were found HPV positive and 7 (6.7%) of them had infection of high-risk HPV type 16. Both urine and later cervical scrapes from a group of 55 women collected as dry 'paper smear' showed perfect matching positivity for HPV between urine and cervical scrape.
Conclusions: The use of urine coupled with its dry collection as 'paper smear' facilitating their easy transport, storage and direct PCR detection of HPV DNA opens up an alternative non-invasive approach for population screening of HPV infection, at least in such cases as children and infants in whom invasive samples are difficult to obtain.