ALTERATION OF MAXIMUM ANAL RESTING PRESSURE BY DIGITAL RECTAL EXAMINATION PRIOR TO MANOMETRY - ANALYSIS OF AGREEMENT BETWEEN REPEAT MEASUREMENTS

To study whether digital examination preceding anal manometry causes s ignificant alteration of maximum resting pressure reading and to quant ify the discrepancies, 78 individuals (64 incontinent, 14 controls) we re investigated. Recordings of maximum resting pressure were taken bef ore and after digital rectal examination. There was a mean discrepancy of only -1.8 cms H2O between the readings and excellent correlation, but analysis of agreement revealed a bias that tended to be greater wi th smaller measurements and unacceptable variability between test resu lts. Furthermore, the bias was not related to age, gender, the grade o f incontinence, maximum voluntary contraction, functional anal canal l ength and threshold volume. Digital rectal examination prior to manome try causes unpredictable results especially in patients with lower max imum resting pressures and should strictly be avoided.