RESUMO
BACKGROUND: In the PGMY-line blot assay, a human beta-globin fragment is co-amplified with human papillomavirus (HPV) DNA, and both analytes are detected by hybridization with probes fixed on a strip in a linear array. The beta-globin DIG-MWP test also detects beta-globin amplicons, but in a microtiter plate-based enzyme immunoassay format. Although the PGMY-line blot assay detected 50 cells per test, the beta-globin DIG-MWP test generated a signal above the detection cut-off with five cells per test. OBJECTIVE: The performance of the beta-globin DIG-MWP assay to detect beta-globin DNA was assessed. STUDY DESIGN: The beta-globin DIG-MWP assay was compared to a standard beta-globin PCR and to the PGMY-line blot strips on 401 genital specimens. Overall, the three beta-globin assays were compared on 325 undiluted lysates, 14 diluted lysates and DNA extracted from 62 lysate samples. RESULTS: Concordance between the PGMY-line blot and the standard beta-globin assay reached 99.5% (399 of 401 results), for a kappa value of 0.95. Concordant results were also obtained between the beta-globin DIG-MWP assay and PGMY-line blot assay for 387 (96.5%) of 401 test results, for a kappa value of 0.57. Discordant results were due to the increased sensitivity of the DIG-MWP assay. Using a cut-off for positivity at 1.500 optical density (OD) units for beta-globin DIG-MWP, concordance improved to 100% (401 of 401 results, kappa at 1.00). CONCLUSION: The beta-globin DIG-MWP assay was adequate to screen for sample adequacy for HPV analysis in genital specimens.
