Hybrid Capture 2 Test Results after an Initial Equivocal RLU/CO Value Are Dependent on Age
Camille T Elkins, Christiaan E de Vries, Julie A Stephens, Adrian A Suarez. The Ohio State University, Columbus, OH
Background: Manufacturer recommended interpretation guidelines for the high risk human papilloma virus (HPV) test Hybrid Capture 2 (HC2) require retesting specimens with an initial equivocal result, defined as a Relative Light Unit/ Cut Off (RLU/CO) value between 1 and <2.5. While a retest with RLU/CO≥1 leads to a “positive” HC2 result, a lower value requires a second retest which is then considered final (“positive” if RLU/CO≥1). However, we have previously documented a low predictive value for cervical intraepithelial neoplasia 2 or worse in women ≥50 years with specimens within the equivocal range and questioned the use of a single interpretative algorithm regardless of age. Therefore, we now decided to investigate the influence of age on HC2 final results produced by the current interpretative algorithm for initial equivocal RLU/CO values.
Design: We identified 365 consecutive cervico-vaginal liquid cytology specimens with initial HC2 HPV tests within the equivocal range. Retest and second retest RLU/CO values were compared for women of three different age groups (15-29, 30-49 and ≥50 years).
Results: The proportion of retests with RLU/CO<1 increased with age (p<0.001 based on Chi-square test).
|Age in Years||RLU/CO<1||RLU/CO≥1||Total|
|15-29||12 (7.4%)||151 (92.6%)||163|
|30-49||28 (20.1%)||111 (79.9%)||139|
|≥50||17 (27%)||46 (73%)||63|