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| IJCEP Copyright © 2007-All rights reserved. |
| International Journal of Clinical and Experimental Pathology |
Int J Clin Exp Pathol 1(3):285-290;2008
Original Article
Papanicolaou Test in the Detection of High-Grade Cervical Lesions: A Re-evaluation
Based on Cytohistologic Non-correlation Rates in 356 Concurrently Obtained Samples
Bhavini Carns and Oluwole Fadare
Department of Pathology, Wilford Hall Medical Center, Lackland AFB, TX 78236, USA; Department of Pathology, Brooke Army Medical
Center, Fort Sam Houston, TX 78234, USA; Pathology Program, San Antonio Uniformed Services Health Education Consortium, San
Antonio, TX 78236; Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
Received 25 Aug 2007; accepted and available online 1 January 2008
Abstract: Studies evaluating the routine Papanicolaou (Pap) test have traditionally used as the reference gold standard, the diagnoses
on the follow-up histologic samples. Since the latter are typically obtained days to weeks after the Pap test, the accuracy of the resultant
comparison may be affected by interim factors, such as regression of human papillomavirus, new lesion acquisitions or colposcopy-
associated variability. A subset of our clinicians have routinely obtained cervical cytology samples immediately prior to their colposcopic
procedures, which presented a unique opportunity to re-evaluate the test performance of liquid-based cervical cytology in detecting the
most clinically significant lesions (i.e. cervical intraepithelial neoplasia 2 or worse: CIN2+), using as gold standard, diagnoses on cervical
biopsies that were essentially obtained simultaneously. For each patient, cytohistologic non-correlation between the Pap test and biopsy
was considered to be present when either modality displayed a high-grade squamous intraepithelial lesion (HGSIL)/CIN2+ while the
other displayed a less severe lesion. Therefore, HGSIL/CIN2+ was present in both the Pap test and biopsy in true positives, and absent in
both modalities in true negatives. In false positives, the Pap test showed HGSIL while the biopsy showed less than a CIN2+. In false
negatives, Pap tests displaying less than a HGSIL were associated with biopsies displaying CIN2+. Combinations associated with
“atypical” interpretations were excluded. A cytohistologic non-correlation was present in 17 (4.8%) of the 356 combinations reviewed. The
non-correlation was attributed, by virtue of having the less severe interpretation, to the Pap test in all 17 cases. There were 17, 322, 0, and
17 true positives, true negatives, false positives and false negatives respectively. The sensitivity, specificity, positive predictive value and
negative predictive value of the Pap test, at a diagnostic threshold of HGSIL, in identifying a CIN2+ lesion were 50%, 100%, 100% and
95% respectively. Even in Pap test/biopsy combinations obtained on the same day by the same colposcopist and evaluated by the same
pathologist, there is a 4.8% (17/356) false negative rate associated with the Pap test. Our findings suggest that there may be an intrinsic
error rate associated with this test modality. (IJCEP708013).
Key Words: Cytohistologic correlation, Pap test, accuracy, sensitivity, specificity, performance, colposcopy
Full Text PDF
Address all correspondences to: Oluwole Fadare, MD, Wilford Hall Medical Center Department of Pathology, 2200 Bergquist Dr., Ste 1,
Lackland AFB, TX 78236, USA, Email address: oluwolefadare@yahoo.com
Original Article
Papanicolaou Test in the Detection of High-Grade Cervical Lesions: A Re-evaluation
Based on Cytohistologic Non-correlation Rates in 356 Concurrently Obtained Samples
Bhavini Carns and Oluwole Fadare
Department of Pathology, Wilford Hall Medical Center, Lackland AFB, TX 78236, USA; Department of Pathology, Brooke Army Medical
Center, Fort Sam Houston, TX 78234, USA; Pathology Program, San Antonio Uniformed Services Health Education Consortium, San
Antonio, TX 78236; Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
Received 25 Aug 2007; accepted and available online 1 January 2008
Abstract: Studies evaluating the routine Papanicolaou (Pap) test have traditionally used as the reference gold standard, the diagnoses
on the follow-up histologic samples. Since the latter are typically obtained days to weeks after the Pap test, the accuracy of the resultant
comparison may be affected by interim factors, such as regression of human papillomavirus, new lesion acquisitions or colposcopy-
associated variability. A subset of our clinicians have routinely obtained cervical cytology samples immediately prior to their colposcopic
procedures, which presented a unique opportunity to re-evaluate the test performance of liquid-based cervical cytology in detecting the
most clinically significant lesions (i.e. cervical intraepithelial neoplasia 2 or worse: CIN2+), using as gold standard, diagnoses on cervical
biopsies that were essentially obtained simultaneously. For each patient, cytohistologic non-correlation between the Pap test and biopsy
was considered to be present when either modality displayed a high-grade squamous intraepithelial lesion (HGSIL)/CIN2+ while the
other displayed a less severe lesion. Therefore, HGSIL/CIN2+ was present in both the Pap test and biopsy in true positives, and absent in
both modalities in true negatives. In false positives, the Pap test showed HGSIL while the biopsy showed less than a CIN2+. In false
negatives, Pap tests displaying less than a HGSIL were associated with biopsies displaying CIN2+. Combinations associated with
“atypical” interpretations were excluded. A cytohistologic non-correlation was present in 17 (4.8%) of the 356 combinations reviewed. The
non-correlation was attributed, by virtue of having the less severe interpretation, to the Pap test in all 17 cases. There were 17, 322, 0, and
17 true positives, true negatives, false positives and false negatives respectively. The sensitivity, specificity, positive predictive value and
negative predictive value of the Pap test, at a diagnostic threshold of HGSIL, in identifying a CIN2+ lesion were 50%, 100%, 100% and
95% respectively. Even in Pap test/biopsy combinations obtained on the same day by the same colposcopist and evaluated by the same
pathologist, there is a 4.8% (17/356) false negative rate associated with the Pap test. Our findings suggest that there may be an intrinsic
error rate associated with this test modality. (IJCEP708013).
Key Words: Cytohistologic correlation, Pap test, accuracy, sensitivity, specificity, performance, colposcopy
Full Text PDF
Address all correspondences to: Oluwole Fadare, MD, Wilford Hall Medical Center Department of Pathology, 2200 Bergquist Dr., Ste 1,
Lackland AFB, TX 78236, USA, Email address: oluwolefadare@yahoo.com