First international proficiency study on human papillomavirus testing in cervical cancer screening.

BACKGROUND: Although cervical screening using Human Papillomavirus (HPV) testing is globally recommended public health policy, there has been no international proficiency studies specifically targeting HPV testing for cervical screening. OBJECTIVE: To obtain the first global overview of the current proficiency of HPV testing services for cervical cancer screening. STUDY DESIGN: A coded proficiency panel of 12 samples containing HPV types 16, 18, 31, 33, 45, 52, 58 or 35/39/51/56/59/68 in human DNA in varying amounts as well as control. Datasets detecting at least a) 10 International Units (IU) of HPV16 and 18, b) 1000 IU of HPV types 31, 33, 45, 52, 58 and c) having no false positives were considered proficient. RESULTS: In total, 84 laboratories worldwide submitted 158 datasets (some laboratories used >1 HPV testing platform). Of those, 122 (77%) were 100% proficient. Only 14/158 datasets (9%) contained false positive results. Comparison of results with assays approved by the Food and Drug Administration (FDA) suggest that future proficiency requirements should also accommodate assays detecting only 100 IU of HPV16/18. A pool of low oncogenicity HPV types that contributed very little to sensitivity, but adversely affected specificity, was detectable by most datasets. CONCLUSION: Internationally recognized proficiency studies of HPV screening, traceable to international standards, provided an overview of current testing performance. There was a high level of proficiency in terms of sensitivity and few false positives, but specificity was not optimal and further research on optimal specificity of HPV screening tests may be warranted.

Improving human papillomavirus (HPV) testing in the cervical cancer elimination era: The 2021 HPV LabNet international proficiency study.

BACKGROUND: Proficient Human Papillomavirus (HPV) genotyping services are essential to support HPV and cervical cancer elimination strategies, in particular to support HPV vaccine research. OBJECTIVES: To perform a global HPV genotyping proficiency study, with evaluation in relation to previous proficiency studies. STUDY DESIGN: The proficiency panel contained 44 coded samples (40 samples containing one or more purified HPV types (HPV6/11/16/18/31/33/35/39/45/51/52/56/58/59/68a/68b) in human DNA, 1 human DNA control and 3 DNA extraction controls). Proficiency required detection of both single and multiple infections of 50 International Units of HPV 16/18, of 500 genome equivalents for other HPV types and no false positivity. RESULTS: One hundred and thirty-two laboratories submitted 211 datasets. Most assays used (182/211 datasets) were commercially available. An all-time high of 75% of the datasets were 100% proficient. One or more false positives were found in 17.5% of datasets. Among laboratories who participated in the 2019 proficiency study, full proficiency increased from 25% in 2019 to 60% in 2021. The high overall proficiency was mostly attributable to a large number of new laboratories, which used similar assays. CONCLUSIONS: The worldwide deterioration in comparability and reliability of HPV testing found in 2019 is now reversed and an overall increase in proficiency is found.

The 2019 HPV Labnet international proficiency study: Need of global Human Papillomavirus Proficiency Testing.

BACKGROUND: Accurate and internationally comparable human papillomavirus (HPV) testing services are essential for cervical cancer elimination programs. The WHO HPV Laboratory Network started issuing international HPV testing proficiency panels in 2008. OBJECTIVES: We report the results of the 2019 global proficiency study and evaluate the proficiency over time. STUDY DESIGN: The proficiency panel contained 40 coded samples containing mixes of purified HPV types (HPV6/11/16/18/31/33/35/39/45/51/52/56/58/59/68a/68b) and 4 controls. Proficiency required detection of both single and multiple infections of 50 International Units of HPV 16/18, of 500 genome equivalents (10x higher concentration) for other HPV types, and no false positives (stricter requirement compared to previous panels). RESULTS: Seventy-eight laboratories submitted 110 datasets with 38 different assays. Most samples (38/44) were reported with 100% proficiency in most datasets. Mostly commercial assays were used (88/110 datasets). Overall, 47.3% of the datasets were 100% proficient. False positivity was detected in at least one sample in 30.1% of datasets. When analysing all datasets ever since 2008 using exactly the same proficiency criteria, there was a steady improvement up to 2017 (the proportion of datasets being completely proficient increased from 25% to 73%). However, in the 2019 proficiency testing the proportion of fully proficient datasets dropped to 50%. CONCLUSIONS: Although we initially documented a worldwide improvement in comparability and reliability of HPV testing services, the trend now appears to be reversed. In response, the International HPV Reference Center will provide support for improved quality of laboratory services, including issuing of global proficiency panels every year.