BACKGROUND The objective of the current study was to determine the effect of reprocessing bloody ThinPrep (TP) samples using a glacial acetic acid technique on the unsatisfactory rate. METHODS During a 12-month study period, all TP gynecologic samples received by the Cytology Laboratory from inpatient, outpatient, and community-based clinics at the University of Texas Southwestern Medical Center and the Parkland Health and Hospital System in Dallas, Texas, were enrolled prospectively into the study. The initial TP slides were evaluated for specimen adequacy based on the 2001 Bethesda System. Any TP sample that contained abnormal cells, by definition, was not considered unsatisfactory. The criteria for reprocessing included scant cellularity in a background of abundant blood. Biopsy correlations for all abnormal cytologic diagnoses were established between TP smears and follow-up biopsies. RESULTS During the course of the 1-year study period, a total volume of 57,296 TP samples were evaluated by the study laboratory. Prior to reprocessing, the laboratory unsatisfactory rate was 8.32% (4767 of 57,296 TP samples). After reprocessing those samples that were compromised by blood (2593 of 4767 TP samples), the unsatisfactory rate was reduced to 5.47% (3134 of 57,296 TP samples), with an overall reduction by 34.25% (2.85 of 8.32 TP samples). Of 2593 samples that were reprocessed, 62.98% (1633 of 2593 TP samples) changed from inadequate to adequate for the purposes of evaluation. Of those 1633 adequate samples, 1509 samples (92.41%) were negative for intraepithelial lesion or malignancy, 72 samples (4.40%) were atypical squamous cells of unknown significance, 5 samples (0.31%) were atypical glandular cells of undetermined significance, 36 samples (2.20%) were low-grade squamous intraepithelial lesions, 10 samples (0.61%) were high-grade squamous intraepithelial lesions, and 1 sample (0.06%) was adenocarcinoma. CONCLUSIONS The authors conclude that the reprocessing of unsatisfactory ThinPrep cervicovaginal cytology samples decrease the unsatisfactory rate considerably, with an increase in the detection of significant abnormal cervicovaginal lesions.