Clinical validation of the full genotyping clart4s HPV assay on Surepath collected screening samples according to the international guidelines for human papillomavirus test requirements for cervical screening

Background / Objectives
Novel HPV assays intended for cervical screening use must be evaluated in accordance with International guidelines for Human Papilloma Virus test requirements for cervical cancer screening. The CLART HPV4S assay (CLART4S, Genomica, Madrid, Spain) is a PCR based microarray assay targeting the L1 region, and the first full-genotyping assay to detect oncogenic HPV genotypes (16, 18, 31,33, 35, 39, 45, 51, 52, 56, 58, 59, 68) and three non-oncogenic-HPV genotypes (6,11, 66) to achieve fulfillment of international validation criteria using SurePath screening samples. Here we present the outcome of the validation of this novel fullgenotyping assay on SurePath collected screening samples, using the GP5+/6+ PCR assay (GP5/6) as a comparator/reference. The genotype concordance between CLART4S and GP5/6 was also assessed.
Results
To assess the performance of the CLART4S assay, SurePath screening samples from women 30 years and above participating in the Danish cervical cancer screening program were collected at Copenhagen University hospital, Hvidovre. For the clinical sensitivity analysis, 81 samples from women with confirmed CIN2 or greater were collected. For the clinical specificity analysis, 1184 samples from 475/490 women with less than CIN2 histology were collected. The assay results were compared to that of the GP5/6 assay in collaboration with Karolinska Institutet, Stockholm. The laboratory performance element involved testing 540 individual samples with known GP5/6 results. The inter-laboratory agreement was performed in collaboration with the Scottish HPV Reference Laboratory in Edinburgh, Scotland.
Conclusion
The relative sensitivity of CLART4S was 91.3% (GP5/6=92.6%) and relative specificity was 90.7% (GP5/6=91.0%). The CLART4S assay was shown to be noninferior to that of GP5/6 for both sensitivity (p=0.00) and specificity (p=0.02). The genotype specific concordance between CLART4S and GP5/6 was good for 12 oncogenic HPV types. The Kappa value for intra-laboratory reproducibility was 0.84 (lower confidence bound 0.92) and for the inter-laboratory agreement the kappa value was 0.72 (lower confidence bound 0.87).