Determining the utility and effectiveness of the NeoPath AutoPap 300 QC System used routinely

To evaluate routine use of the NeoPath AutoPap 300 QC System (AP 300) as it influences diagnostic quality and operations in a large cytology laboratory.

During a three-month period, 35,143 conventionally prepared consecutive cervical cytologic smears taken from non-high-risk women and evaluated as negative by our staff of 25 cytotechnologists were selected for processing by four AP 300 instruments. Slides flagged for review by the AP 300 were reevaluated by our five quality control (QC) cytotechnologists. False negative (FN) results were compared with results of our current practice (CP), random-selection QC method, used during the preceding six months.

A 240% increase was seen in the FN detection rate for atypical squamous cells of undetermined significance (ASCUS) and squamous intraepithelial lesions (SIL) (n AP = 65 FN in 5,034 QC, n CP = 77 FN in 22,052 QC) and a 744% increase in the FN detection rate for low and high grade SIL (n AP = 24 FN/5,034 QC, n CP = 12 FN/22,052 QC). The rate of overcall by cytotechnologists did not increase. The QC ASCUS/SIL ratio improved. FN biopsy correlation increased from 45% to 85% (n CP = 17/38 agreement, n AP = 23/27 agreement). Turnaround time increased by one or more days for negative and 1.5 days for QC result reporting. Sensitivity varied among instruments.

More FN results and greater specificity were seen using the AP 300 than using CP. As with other instrumentation, each laboratory should establish acceptable ranges of performance and baseline values for sensitivity and specificity.