Study Shows Labs Should Specify HPV Assay Used
By Labmedica International staff writers
Posted on 24 May 2018
Image: The Cervista HPV HR assay, a cervical cancer rapid diagnostic test for human papillomavirus (HPV) (Photo courtesy of Hologic).
Human papillomavirus (HPV) is a double-stranded DNA virus that infects squamous and glandular epithelial cells in the ectocervix and endocervix and integrates its genome into the host DNA, causing either an active or a latent infection without detectable symptoms.
The two most common methods of testing for HPV DNA are Hybrid Capture 2 and polymerase chain reaction. The DNA-based HPV assay detects the presence or absence of an HPV infection and cannot distinguish between an active and a latent infection. A negative DNA test signifies that there is no HPV infection present.
Scientists at the Memorial Hermann Hospital (Houston, TX, USA) carried out a retrospective study of pathology charts that were electronically searched to identify women older than age 30 years who had had at least one positive HPV DNA result reported in the laboratory system before November 2014 and also had results from at least one HPV mRNA assay reported between November 2014 and June 2016. The age of 30 years was selected intentionally because “older” age is associated with a greater likelihood of a persistent HPV infection.
All HPV test results, cytology, and colposcopic-directed biopsy results were entered into a deidentified electronic database by the data extractor. The mRNA test utilized is the APTIMA HPV assay and the DNA test used is the Cervista HPV-HR assay. Both tests were created by Hologic (Marlborough, MA, USA) and detect the same 14 HPV high-risk types. The sensitivity and specificity for each respective assay are readily available.
The team identified 425 charts for female patients 30 years of age or older with one or more prior high-risk HPV infections by DNA assay. There was a 69.3% difference in HPV mRNA results compared with previous HPV DNA–positive results. There was a potential change in follow-up for 71.7% of patients with one prior high-risk-HPV-positive result and 60.0% of patients with two or more prior high-risk HPV-positive results. There were 231 colposcopy reports evaluated in this study. Of these, 62 (26.8%) were abnormal colposcopy reports, including 45 low-grade squamous intraepithelial lesions, 15 high-grade squamous intraepithelial lesions, and two cancers. Twenty-five (40.3%) abnormal colposcopy findings were in patients with a history of at least than two prior HPV DNA–positive results and a report of currently being HPV-negative with the mRNA assay.
The authors concluded that the HPV mRNA assays are less sensitive for detection of latent HPV infections compared with HPV DNA assays. Based on these data and the potential change in follow-up care, the HPV mRNA assay should not be used for a primary screening tool for cervical cancer. Many pathology laboratories have shifted to using the HPV mRNA assay without clear discussion with gynecologists about the effects on patient follow-up. The type of HPV assay being used should be documented and any HPV mRNA result confirmed by HPV DNA assay. The study was published in the April 2018 issue of the journal Obstetrics and Gynecology.