[1855] Making a Case for Rapid Prescreening of Pap Tests in Quality Assurance/Quality Control and Systems Based Approach to Reducing Errors.

Vijayalakshmi Padmanabhan, Samuel Q Armstrong, Diane M Green, Francis M Quinlisk, Susan L Augustinowicz, Vickie E Johncox. Dartmouth Hitchcock Medical Center, Lebanon, NH

Background: To increase the sensitivity of Pap tests, 10% of randomly selected negative Papanicolaou (Pap) smears are rescreened as a quality control (QC) measure. This has been mandated to reduce the false negative rate. Recently, there has been an interest in alternatives to the 10% QC, either rapid prescreening (RPS) or rapid rescreening (RRS). In the United Kingdon, RPS is the most widely used QC method though this is not the practice in the U.S. In this study, we use RPS as a tool for QC and as a system absed approach to reduce errors.
Design: Four hundred and forty seven ThinPrep Pap test smears were reviewed. These cases were initially processed on the ThinPrep Image system. RPS was performed by the cytopatholgy supervisor at a rate of 1 slide a minute. Additional time was taken to enter the interpretation in a standardized work sheet. No marks were made on these slides. These cases were then given to the cytotechnologists for review on the ThinPrep Image system review microscopes. RPS diagnosis and final diagnosis by the cytotechnologists and/ or the cytopathologists were noted (Table 1). Cases where the RPS diagnosis and the final diagnosis were negative were not reviewed; but cases with a difference of diagnosis between the 2 were reviewed. After a full manual rescreen, those cases that needed review by the pathologist were submitted to the pathologist. Cases with 10% QC diagnosis were also noted (Table 2).
Results:

Table 1
n= 447RPSFD
Unsatisfactory45
NILM383398
Ractive/ Repair39
ASCUS3723
ASC-H03
LSIL167
LSIL, cannot exclude HSIL12
HSIL30
Rapid prescreening (RPS) assessment versus final diagnosis (FD)



Table 2
 RPS10% QC review
ASCUS64
ASC-H20
LSIL10
Total94
RPS versus 10% QC review diagnosis


Conclusions: RPS identified more disease (9 cases) than the 10% QC (4 cases); 2.01% versus 0.89% respectively. Automated rescreening methods have been shown to be better than manual rescreening in some studies. In spite of using automated methods like the ThinPrep image system, the final interpretation is given by the cytotechnologist who has to decide whether the cells present in the fields of view are abnormal. The experience of the cytotechnologists varies in most laboratories, including ours. This is a good system-based approach to monitor new cytotechnologists and improve sensitivity and reduce false negative rates in the laboratory. In summary RPS is an inexpensive and efficient method to improve the sensitivity of the Pap test.
Category: Quality Assurance

Monday, February 28, 2011 1:00 PM

Poster Session II # 221, Monday Afternoon

 

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