Atypical epithelial cells and specimen adequacy: current laboratory practices of participants in the college of American pathologists interlaboratory comparison program in cervicovaginal cytology.

CONTEXT

The Bethesda System for reporting cervical/vaginal cytologic diagnoses introduced terminology for atypical squamous and glandular cells and categories for specimen adequacy.

OBJECTIVES

To analyze current laboratory reporting practices and compare trends to previous surveys.

DESIGN

Questionnaire surveys were mailed to 2000 laboratories in 1996 and 1997.

PARTICIPANTS

Laboratories enrolled in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology.

MAIN OUTCOME MEASURES

Laboratory policies, criteria, and reporting rates for Bethesda System categories.

RESULTS

The 1996 specimen adequacy survey had 1166 respondents, and 768 laboratories returned the 1997 questionnaire focusing on atypical squamous cells of undetermined significance (ASCUS) and glandular cells of undetermined significance (AGUS). Nearly all laboratories (92%) routinely reported specimen adequacy, an increase from the 66% rate in 1991. The median rate for unsatisfactory specimens was 0.5% (mean 0.95%), and the median rate for the satisfactory but limited category was 5.8% (mean 9.3%). The Bethesda criteria for designating a specimen unsatisfactory were used by more than 90% of laboratories. Nearly all laboratories (97%) used the term ASCUS in 1997, and more than 80% of laboratories used the Bethesda criteria for this category. Median reporting rates for epithelial abnormalities were as follows: ASCUS, 4.5%; AGUS, 0.3%; low-grade squamous intraepithelial lesion (SIL), 1.6%; and high-grade SIL, 0.5%. The median ASCUS/SIL ratio was 2.0, with 80% of laboratories reporting ratios between 0.64 and 4.23. The median ASCUS rate and ASCUS/SIL ratio were higher than 1993 survey results. Nearly all laboratories attempted follow-up studies on patients with abnormal cytology results, and midsized laboratories achieved the highest rates of follow-up. Median rates of abnormalities following an ASCUS or AGUS diagnosis were 20% and 15%, respectively. Laboratory respondents commonly used written recommendations in ASCUS/AGUS reports.

CONCLUSIONS

Most laboratories that responded to the surveys had adopted Bethesda terminology and criteria for specimen adequacy and ASCUS/AGUS. Reporting rates for SIL and adequacy categories have remained stable, but median ASCUS rates and ASCUS/SIL ratios are higher than in 1993. The AGUS category is reported infrequently, but can be associated with significant pathology.