Results of the first World Health Organization international collaborative study of detection of human papillomavirus DNA

Abstract

Twenty-nine laboratories in 12 countries participated in a study to assess the performance of various human papillomavirus (HPV) detection assays through the use of a recombinant HPV DNA standard reagent panel. The panel was designed by a group of HPV experts, and samples were prepared and distributed by the World Health Organization International Laboratory for Standards and Biologicals in The Netherlands. Each panel consisted of 24 coded samples including a dilution series for HPV types 16 and 18, alone or in combination with five other high-risk (HR) HPV types including HPV types 31, 33, 35, 45, and 52, the low-risk HPV type 6, and a negative control. Qualitative assays were generally consistent across laboratories, and most invalid results reflected a lack of HPV test sensitivity. The combined data sets had a proficiency for HPV 16 of 62.5% (15/24) and for HPV 18 of 73.9% (17/23). HPV 31 was the least accurately detected by participating laboratories. Approximately half of participating laboratories failed to detect high concentrations of HPV 31 and, to a lesser extent, to detect HPV types 35, 52, and 6. The panel sample materials offer a source of renewable and reproducible material that could be used in the future development of international standard reagents for calibration of HPV DNA assays and kits.

FIG. 1.

Linearity of HPV 16 and HPV 18 plasmid DNA dilution series. C_T, cycle threshold; y, slope. The theoretical ideal slope is expressed as y = −3.34x. Values for the input log (dilution) are as follows: 0, 10⁻⁹; 1, 10⁻⁸; 2, 10⁻⁷; 3, 10⁻⁶; 4, 10⁻⁵; and 5, 10⁻⁴.

FIG. 2.

Ability to detect HPV DNA 16 and 18. Each reference and each participating laboratory are listed on the top row from 1 through 19. Participating laboratories are identified as letters of the alphabet from A to U. Methods used for HPV DNA detection are identified as numbers from 1 through 19. Gray boxes, correct detection (positive); blank boxes, no detection (negative); dark boxes, incorrect detection (false positive); light gray boxes, not performed. Samples for HPV 16 and HPV 18 are listed to the left as dilution series (in descending order of DNA concentration). Actual numbers of the coded samples are listed to the left, in addition to the HPV types and dilutions.