Assessment of MagNA pure LC extraction system for detection of human papillomavirus (HPV) DNA in PreservCyt samples by the Roche AMPLICOR and LINEAR ARRAY HPV tests

Roche Molecular Systems recently released two PCR-based assays, AMPLICOR and LINEAR ARRAY (LA), for the detection and genotyping, respectively, of human papillomaviruses (HPVs). The manual specimen processing method recommended for use with both assays, AmpliLute, can be time-consuming and labor-intensive and is open to potential specimen cross-contamination. We evaluated the Roche MagNA Pure LC (MP) as an alternative for specimen processing prior to use with either assay. DNA was extracted from cervical brushings, collected in PreservCyt media, by AmpliLute and MP using DNA-I and Total Nucleic Acid (TNA) kits, from 150 patients with histologically confirmed cervical abnormalities. DNA was amplified and detected by AMPLICOR and the LA HPV test. Concordances of 96.5% (139 of 144) (kappa = 0.93) and 95.1% (135 of 142) (kappa = 0.90) were generated by AMPLICOR when we compared DNA extracts from AmpliLute to MP DNA-I and TNA, respectively. The HPV genotype profiles were identical in 78.7 and 74.7% of samples between AmpliLute and DNA-I or TNA, respectively. To improve LA concordance, all 150 specimens were extracted by MP DNA-I protocol after the centrifugation of 1-ml PreservCyt samples. This modified approach improved HPV genotype concordance levels between AmpliLute and MP DNA-I to 88.0% (P = 0.043) without affecting AMPLICOR sensitivity. Laboratories that have an automated MP extraction system would find this procedure more feasible and easier to handle than the recommended manual extraction method and could substitute such extractions for AMPLICOR and LA HPV tests once internally validated.