Single Visit Clinical Validation of ScreenFire, a Low-cost HPV Test

ScreenFire HPV test (Atila BioSystems, Inc, Mountain View, CA) uses isothermal amplification to detect 13 high risk (hr)HPV types directly from clinical samples in approximately one hour. The test can be run on any real-time PCR machine and gives separate results for hrHPV types 16 and 18, as well as a pooled positive result for 13 other hrHPV types. The human cellular gene beta-globin is used as an internal control to measure sample adequacy. ScreenFire can be self-collected and does not require batching. AmpFire® obtained CE-mark in 2017.

The careHPV (QIAGEN, Gaithersburg, MD) test was developed in a public-private partnership specifically for use in low-resource settings. It is a simplified, robust, and affordable HPV test that does not distinguish specific HPV types; rather, it gives a positive result if any of 14 hrHPV types is present in the specimen. Electricity is necessary to run the test, but it does not need running water or air conditioning. In order to be most cost effective, the samples must be run with a full plate of 96 samples. Results take 3-4 hours to complete.

A colposcopic exam with biopsy entails visual magnification of the cervix and the removal of a small piece of cervical tissue. After the application of acetic acid 5% onto the cervix, a device called a colposcope allows the clinician to visually identify changes consistent with HPV. Areas of the cervix where lesions appear (or if not, randomly selected sections) are then biopsied (small piece of sample removed) and an endocervical curettage is performed (removing a small section from the inside of the cervix). Tissue specimens are then sent to the lab for pathology diagnosis.

"Cryotherapy is performed to treat high-grade cervical precancer. First, a speculum is introduced into the vagina to identify the cervix. Acetic acid 5% is applied to the cervix for one minute and the cervix is observed to look for changes consistent with precancer. If the cervix is able to be fully evaluated and there are no signs of invasive cancer, a metal probe is inserted into the vagina and the tip is pressed against the cervix. Compressed carbon dioxide or nitrous oxide gas at a temperature of approximately -50ºC/-58ºF freezes the tip and creates an ice ball on the cervix. The ice ball ablates or destroys the abnormal cells."

Thermal ablation is utilized to treat high-grade cervical precancer. First, a speculum is introduced into the vagina to identify the cervix. Acetic acid 5% is applied to the cervix for one minute and the cervix is observed to look for changes consistent with precancer. If the cervix is able to be fully evaluated and there are no signs of invasive cancer, the tip of the device is heated to 100ºC and applied directly to the cervix for 1-2 minutes, which ablates or destroys the abnormal cells.