False-positive Papanicolaou (PAP) test rates in the College of American Pathologists PAP education and PAP proficiency test programs: evaluation of false-positive responses of high-grade squamous intraepithelial lesion or cancer to a negative reference diagnosis.
BACKGROUND
In cytology proficiency testing (PT), participants fail for incorrectly interpreting a high-grade squamous intraepithelial lesion or cancer (HSIL+) Papanicolaou test result as negative. This penalty may lead to a false-positive interpretation of negative slides as HSIL+ to avoid failure.


OBJECTIVE
To investigate factors related to false-positive responses in a PT versus an educational environment.


METHODS
We analyzed 420,079 responses from 9414 validated negative reference slides in the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytopathology (PAP Education) and compared them with responses from the Gynecologic Cytology Proficiency Testing Program for the percentage of false-positive (HSIL+) interpretations in each of 7 negative subcategories. We evaluated the influence of preparation type (ThinPrep, SurePath, and conventional Papanicolaou test), participant type (pathologist or cytotechnologist), and program time interval (preproficiency test or PT) on a false-positive response.


RESULTS
Reference diagnosis and participant type, but not preparation type, were statistically correlated to false-positive responses. The interaction between program time interval and participant type was also significant. Pathologists had higher rates of false-positive results on preproficiency test (1.2% [800 of 68,690]) than they did on PT (0.8% [993 of 129,857]). Cytotechnologists had no differences between program time intervals (preproficiency, 0.9% [515 of 63,281] versus PT, 1.0 [1231 of 121,621]; P = .91). Negative subcategories frequently mistaken for HSIL+ were reparative changes (4.7% [427 of 9069]), atrophic vaginitis (1.8% [18 of 987]), and negative for intraepithelial lesion or malignancy (1.2% [2143 of 178,651]), but during PT, false-positive rates were significantly increased only for the negative for intraepithelial lesion or malignancy and herpes simplex virus (P < .001).


CONCLUSIONS
Pathologists had lower false-positive rates in the Gynecologic Cytology Proficiency Testing Program than they did in PAP Education, but participants were more likely to report a false-positive response (HSIL+) for negative for intraepithelial lesion or malignancy and herpes simplex virus in the Gynecologic Cytology Proficiency Test Program.
From the Department of Pathology and Laboratory Medicine, Walter Reed National Military Medical Center, Bethesda, Maryland (Dr Crothers); the Department of Anatomic Pathology, Cleveland Clinic Foundation, Cleveland, Ohio (Dr Booth); the Pathology Cytopathology Laboratory, Mount Zion Medical Center Clinic, University of California, San Francisco (Dr Darragh); Department of Pathology, Magee-Women's Hospital of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Dr Zhao); and the Departments of Statistics/Biostatistics (Ms Souers), CAP PAP Program (Ms Thomas), and Pathology (Dr Moriarty), College of American Pathologists, Northfield, Illinois.
Barbara A
BA
Crothers
Christine Noga
CN
Booth
Teresa Marie
TM
Darragh
Chengquan
C
Zhao
Rhona J
RJ
Souers
Nicole
N
Thomas
Ann T
AT
Moriarty
D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000453:epidemiology; D003951:Diagnostic Errors / Q000706:statistics & numerical data; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D015994:Incidence; D059021:Laboratory Proficiency Testing / Q000592:standards*; D065006:Papanicolaou Test / Q000706:statistics & numerical data*; D010338:Pathology, Clinical / Q000193:education*; D011361:Professional Competence / Q000592:standards*; D012015:Reference Standards; D012189:Retrospective Studies; D013997:Time Factors; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis* / Q000453:epidemiology