PAP/NGC Programs Review
Q. Our laboratory maintains cytology/histology correlation in a separate
file and keeps track of any discrepancies noted. We send out a letter to clinicians
for all abnormal cytology cases without correlation asking for documentation
of followup. We have several questions about these correlations: Should a comment
on correlation be included in our pathology reports? When should requests for
followup be made, and what should be done with this information?
A. CLIA ’88 mandates that there is laboratory comparison
of clinical information, when available, with cytology reports and comparison
of all gynecologic cytology reports with a diagnosis of high-grade squamous
intraepithelial lesion (HSIL), adenocarcinoma, or other malignant neoplasms
with the histopathology report, if available in the laboratory (either on-site
or in storage), and determination of the causes of any discrepancies.1
These requirements are reflected in cytopathology checklist questions CYP.01900,
CYP.07543, CYP.07556, and CYP.07569.2
The method for documenting the cytohistologic correlation results is not specified
and is left to each individual laboratory’s discretion. Communication
of cytology and biopsy correlation results to clinicians is key and provides
critical information for optimal patient management.6
Cytohistologic correlation for individual patients can be documented in biopsy
reports, via phone calls, or in letters, and, in more general terms, correlation
statistics can be discussed in interdepartmental committees or conferences.
Evaluation of cytohistologic correlations is also an important part of a laboratory’s
quality improvement program.10 The definition
of what constitutes diagnostic discrepancy should be established, and it should
be recognized that perfect correlation is not realistic. The 1996 CAP Q-Probes
study5 of 22,429 paired cervicovaginal cytology
and biopsy specimens reported a discrepancy rate of 16.5 percent with a Pap
sensitivity of 89 percent and specificity of 65 percent. The majority of discrepancies
in this study were due to sampling differences rather than screening or interpretive
errors. Because both the Pap test and colposcopic biopsy are subject to sampling
errors, reasons for discrepancies should be pursued when the biopsy is negative,
as it may not always represent the gold standard. Negative cytology cases should
also be reviewed, if available, when the biopsy is positive. Peer or multidisciplinary
review or both of noncorrelating specimens may be helpful in achieving consensus.
Regular summary and evaluation of results can identify trends and improvements.
There is no requirement for correlating biopsies with lesser abnormalities,
for correlating subsequent cytology with previous biopsies, or for correlating
concurrent biopsies. However, these cytohistologic correlations are recorded
in many laboratories and may be a useful part of the quality improvement program.
Laboratories are required to document the number of cases that do have histologic
correlation in the annual laboratory cytology statistical report.
In a 1997 article by Andrew Renshaw, MD,7
the optimal time for correlation of cytology and subsequent biopsies was found
to be between 60 to 100 days, during which time the correlation of the Pap test
and the subsequent biopsies was the highest. Biopsies performed over 100 days
were less likely to correlate with the initial Pap. The difference may be explained
by regression of lesions over time.
When followup material is not available in the laboratory, documentation of
followup correspondence or reports, telephone calls, or requests for information,
whether as separate letters or in the histology report, must be maintained and
kept for two years. In cases without biopsy followup, other studies such as
human papillomavirus testing, repeat Pap tests, and colposcopic examination
findings may provide useful information, especially in cases of HSIL, glandular
abnormalities, and carcinoma.
1. Department of Health and Human Services, Centers for Medicare and Medicaid
Services. Clinical Laboratory Improvement Amendments of 1988; final rule. Fed
Register. 2003(Jan 24):3712 [42 CFR493.1274(c)(2)].
2. College of American Pathologists Laboratory Accreditation Program. Cytopathology
checklist, January 2005.
3. Joste NE, et al. Cytologic/histologic correlation for quality control in
cervicovaginal cytology. Experience with 1,582 paired cases. Am
J Clin Pathol. 1995;103:32–34.
4. Tritz DM, Weeks JA, Spires SE, et al. Etiologies for non-correlating cervical
cytologies and biopsies. Am
J Clin Pathol. 1995;103:594–597.
5. Jones BA, Novis DA. Cervical biopsy-cytology correlation. A College of American
Pathologists Q-Probes study of 22439 correlations in 348 laboratories. Arch
Pathol Lab Med. 1996;120:523–531.
6. Wright TC, Cox JT, Massad LS, et al. 2001 consensus guidelines for the management
of women with cervical cytological abnormalities. JAMA.
7. Renshaw A, Granter SR. Appropriate follow-up interval for biopsy confirmation
of squamous intraepithelial lesions diagnosed on cervical smear cytology. Am
J Clin Pathol. 1997;108:275–279.
8. Hindman WM. An approach to the problem of false negatives in gynecologic
cytologic screening. Acta
9. Clary KM, et al. Cytohistologic discrepancies. A means to improve pathology
practice and patient outcomes. Am
J Clin Pathol. 2002;117:567–573.
10. Nakhleh RE, Fitzgibbons PL, eds. Quality Improvement Manual in Anatomic
Pathology. 2nd ed. Northfield, Ill.: College of American Pathologists;
Margaret Havens Neal, MD
KWB Pathology Associates
Member, CAP Cytopathology Committee