External quality assessment for human papillomavirus 16/18 DNA detection and genotyping in Shanghai, China

Human papillomavirus (HPV) DNA detection and genotyping is now being used for cervical screening by a growing number of laboratories in Shanghai, but they may have various levels of proficiency. The objective of this study was to evaluate the performance of clinical laboratories for HPV DNA detection and genotyping by an external quality assessment (EQA) program.

The EQA panels were clinically validated by the Cobas 4800 HPV test, and then distributed to the participating laboratories in May 2015 (round 1) and September 2015 (round 2). Each panel consisted of one negative sample and nine positive cell or clinical samples of HPV16 and HPV18 types at different concentrations. In total, 40 laboratories submitted 18 qualitative and 22 genotyping data sets in round 1 and 44 laboratories submitted 18 qualitative and 26 genotyping data sets in round 2. In both rounds, all laboratories used commercial assays.

The negative samples were detected correctly in both rounds by all participating laboratories. There were no false-positive results in the qualitative data sets and only two false-positive results in the genotyping data sets in each of round 1 and round 2. The false-negative rates were 8.0% for round 1 and 2.7% for round 2. For the qualitative data sets, almost all of the laboratories (100% for round 1 and 97.8% for round 2) obtained a score of acceptable or better. For the genotyping results, acceptable or better scores were obtained in 81.8% (round 1) and 100% (round 2).

Our results indicate that the majority of laboratories in Shanghai have reliable diagnostic ability for HPV detection and genotyping. Moreover, this study emphasizes the importance of EQA for monitoring the performance of clinical laboratories.