A validation study of the FocalPoint GS imaging system for gynecologic cytology screening.

BACKGROUND: Studies of the performance of the automated FocalPoint Guided Screening (FPGS) imaging system in gynecologic cytology screening relative to manual screening have yielded conflicting results. In view of this uncertainty, a validation study of the FPGS was conducted before its potential adoption in 2 large laboratories in Ontario. METHODS: After an intense period of laboratory training, a cohort of 10,233 current and seeded abnormal slides were classified initially by FPGS. Manual screening and reclassification blinded to the FPGS results were then performed. Any adequacy and/or cytodiagnostic discrepancy between the 2 screening methods subsequently was resolved through a consensus process (truth). The performance of each method's adequacy and cytodiagnosis vis-a-vis the truth was established. The sensitivity and specificity of each method at 4 cytodiagnostic thresholds (atypical squamous cells of undetermined significance or worse [ASC-US+], low-grade squamous intraepithelial lesion or worse [LSIL+], high-grade squamous intraepithelial lesion or worse [HSIL+], and carcinoma) were compared. The false-negative rate for each cytodiagnosis was determined. RESULTS: The performance of FPGS in detecting carcinoma, HSIL+, and LSIL+ was no different from the performance of manual screening, but the false-negative rates for LSIL and ASC-US were higher with FPGS than with manual screening. CONCLUSIONS: The results from this validation study in the authors' laboratory environment provided no evidence that FPGS has diagnostic performance that differs from manual screening in detecting LSIL+, HSIL+, or carcinoma.

Aptima Combo 2 testing detected additional cases of Neisseria gonorrhoeae infection in men and women in community settings.

Aptima Combo 2 (AC2) Neisseria gonorrhoeae testing of 81,405 patients who were tested by culture and 14,666 who were AC2 tested for Chlamydia trachomatis detected 142 extra infections and confirmed 106 culture-positive samples (the positivity rate increased from 0.13 in testing by culture to 0.26 in testing by AC2). Retrievable AC2 positive samples were confirmed (98.5%) by an alternate AGC test.

Comparative evaluation of AMPLICOR HPV PCR and Linear Array assays on SurePath liquid-based Pap samples for the detection of high-risk HPV genotypes.

BACKGROUND: Persistent cervical infection with high-risk [HR] HPV is a causative factor for cancer. Liquid-based [L-Pap] Pap samples are convenient for HPV testing and SurePath samples have been least studied. Most HPV tests have multiple step protocols and testing laboratories experience large volumes of samples. OBJECTIVES: Using SurePath L-Pap residual samples the objectives were as follows: [1] to test the performance of AMP-HPV and LA-HPV. [2] To perform an agreement study between two laboratories for the AMP-HPV test and [3] to compare agreement of results between AMP-HPV and LA-HPV and HC2. STUDY DESIGN: Samples from 657 women were tested for Pap cytology then assayed for HR-HPV using AMP-HPV and LA-HPV tests. AMP-HPV performance was compared between 2 laboratories and agreement studies were conducted between AMP-HPV, LA-HPV and HC2. RESULTS: HR-HPV genotypes were associated with L-Pap readings as follows: HSIL 92% [23/25], LSIL 73.6% [162/220], ASCUS 70.4% [131/186], normal 31.9% [72/226]. More women less than 30 were infected with HR-HPV and multiple genotypes regardless of the L-Pap reading. AMP-HPV and LA-HPV testing had an overall raw agreement with each other of 84.2% [Kappa 0.66] and each had agreement of 94% with HC2 testing of 133 samples [Kappa 0.86/0.87]. AMP-HPV agreement between two laboratories was better at 93% [Kappa 0.84] compared to 76.1% [Kappa 0.40] when extraction was standardized. CONCLUSION: It is feasible to perform AMP-HPV and LA-HPV on SurePath samples to detect HR-HPV genotypes. HC2, AMP-HPV and LA-HPV showed strong agreement. The extraction component of the AMP-HPV assay needs careful attention to yield consistent results.

Validation of the APTIMA Combo 2 assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in SurePath liquid-based pap test samples taken with different collection devices.

Mocked samples of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) diluted in SurePath liquid-based Pap (L-Pap) fluid were detected by the APTIMA Combo 2 assay to end points 10-fold greater than dilutions in specimen transport media. Pooled L-Pap clinical specimens yielded CT-positive results after storage at room temperature for 10 days. Based on an infected patient standard for comparison, cervical swabs, urine, and SurePath L-Pap test samples collected with a SurePath cervical broom or ThinPrep cytobrush from 520 women then tested by APTIMA Combo 2 assay, detected 25 (4.8%) with CT, 5 (1.0%) with (GC), and 3 (0.6%) with both. Percent sensitivities (80-84), specificities (99.8-100), positive (99.5-100) and negative (99.2-99) predictive values of SurePath L-Pap for CT were validated as similar to those reported in a previously published multicenter trial. All values for GC were 100%. One collection device was not significantly better than the other.