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Improved anal Cytology Sampling



The objective of this study was to determine the performance characteristics of the Tush brush (TB) compared with a saline moistened Dacron swab (DS) as anal cytology sampling devices.

Materials and methods

TB and DS anal cytology tests were randomly collected from 146 patients presenting for anal cytology. High-resolution anoscopy and biopsies were obtained as indicated. Sensitivity and specificity as well as rates of satisfactory specimens were determined for each method using the areas under the receiver operating characteristic curve (AUCROC) and McNemar's test, respectively. Perceived discomfort of each device was determined using a visual analog scale and compared using a paired t test.


The adjudicated AUCROC, sensitivity, and specificity were greater, but not significantly different, for the brush (0.63, 85.5, and 40.0, respectively) compared with the swab (0.50, 79.6, and 33.3, respectively) when the anal biopsy results were considered the criterion standard. In the 1 subject diagnosed with anal cancer, the swab cytology result was normal, but the brush result was abnormal. Specimen adequacy was 95.2% for the brush and 93.2% for the swab. Mean discomfort (visual analog scale) scores were swab 28.5 mm versus brush 35.6 mm (p = .0003) with both scores within the minimal to moderate discomfort range.


Anal cytology AUCROC, sensitivity, and specificity in detecting anal neoplasia were greater using the TB when compared with the DS. A novel anal cytology sampling device designed specifically to increase the detection of anal neoplasia would be clinically beneficial.

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