Factors contributing to high ThinPrep® Pap test unsatisfactory rates in an academic medical center laboratory

Specimen adequacy is a key component in the cytologic evaluation of cervical Pap tests. At our institution, yearly unsatisfactory rates continue to be high, placing our laboratory in the 95th percentile for CAP benchmark data for unsatisfactory Pap test rates. Using the 2001 Bethesda System criteria, unsatisfactory Pap test rates were calculated over a ten year period (January 2002 to December 2011) and contributing factors were analyzed. Of the 124,457 ThinPrep Pap tests performed, 4,163 (3.3%) were unsatisfactory for evaluation, the majority (90%) due to too few squamous epithelial cells. Peri/postmenopausal women and those who had received radiation/chemotherapy had the highest unsatisfactory rates; 55% and 25%, respectively. Higher unsatisfactory Pap test rates are related to the patient population served. Defined, reproducible adequacy criteria need to be defined for Pap tests from patients in certain clinical conditions.