College of American Pathologists
Printable Version

  PAP/NGC Program Review


cap today

May 2003
Special Section

Is there a right time for cyto/histo correlation in gyn cytology?

Andrew A. Renshaw, MD

Cytologic-histologic correlation is an important component of any
quality improvement program in cytology. A documented effort must be made to obtain and review follow-up histologic reports or material that is available within the laboratory when high-grade squamous intraepithelial lesion or malignant findings are identified in gynecologic cytology.1 There is no specific requirement to obtain correlation for any gynecologic cytology specimen in the absence of HSIL, and there is no specific requirement that histologic findings be correlated with cytologic findings, though many laboratories do make these correlations and the results certainly can be a component of a quality improvement program.2-5

The time period over which these correlations should be made is not specified. Data do suggest, however, that the optimal period for examination may be 60 to 100 days. In a study involving 419 low-grade squamous intraepithelial lesion and 277 HSIL smears, Renshaw, et al.6 correlated the rate of subsequent biopsy and the rate of correlation with that biopsy over a period of one year. In this study, 811 biopsies were performed. While biopsies that correlated with the initial cytologic finding could be identified as late as one year after the initial cytology, the highest rate of confirmation was obtained in biopsies performed within 60 days, and fully 78 percent of all correlating biopsies were obtained within the first 100 days. The chance of finding a correlating smear decreased after that time. In other words, biopsies performed more than 100 days after the initial biopsy were less likely to correlate with the initial cytologic finding.

One explanation for the increased number of discrepancies was regression of the lesions. After 100 days, there is a greater likelihood of regression, which leads to an increase in the number of perceived “false-positive” cytology results when, in fact, a number of them are actually true positives. Limiting correlations to 100 days after the cytologic specimen was obtained is a reasonable way to limit the impact of “false-positive” correlations on the quality improvement program and the cytologic staff, while at the same time obtaining the majority of all biopsies for which correlation is available.

More controversial is whether cytologic specimens should be taken at the same time as the biopsy and correlated with it. Some literature suggests that cytologic specimens taken at that time have a higher likelihood of being false-negatives—that is, the cytologic specimen is more likely to not sample the lesion found in the biopsy.7 In the study by Renshaw, et al.,6 this was not found to be the case, and indeed cytologic specimens obtained at the time of biopsy were more likely to correlate with the results of biopsy than cytologic specimens taken at any subsequent time.

No requirement specifies that concurrent Pap tests need to be correlated with the biopsy since these cytology specimens were not the reason for obtaining the biopsy. Technically concurrent biopsies are not a followup to the cytology. In the interests of patient care, however, HSIL or malignancy identified on the cytology specimen with a concurrent negative or low-grade biopsy result should be reconciled. Furthermore, the subsequent histologic specimens must be correlated. It appears that the optimal biopsies to correlate are those obtained within 60 to 100 days after the Pap test.


  1. College of American Pathologists. Laboratory Accreditation Program. Cytopathology checklist, Nov. 22, 2002. Question CYP.07543.
  2. Joste NE, Crum CP, Cibas ES. Cytologic/histologic correlation for quality control in cervicovaginal cytology. Am J Clin Pathol. 1995;103:32-34.
  3. Tritz DM, Weeks JA, Spires SE, et al. Etiologies for non-correlating cervical cytologies and biopsies. Am J Clin Pathol. 1995; 103:594-597.
  4. Jones BA, Novis DA. Cervical Biopsy-Cytology Correlation. Arch Pathol Lab Med. 1996;120:523-531.
  5. Wright TC, Cox JT, Massad LS, et al. 2001 consensus guidelines for the management of women with cervical cytological abnormalities. JAMA. 2002;287: 2120-2129.
  6. 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.
  7. Hindman WM. An approach to the problem of false negatives in gynecologic cytologic screening. Acta Cytol. 1989;33: 814-818.