the patient may verbalize an awareness of bladder fullness and sensation of incomplete bladder emptying. Signs and symptoms og UTI (hematuria, urgency, frequency, nocturia, and dyturia) may be present. A series of urodynamic studies, described in chapter 26, may be performed to identity the type of bladder dysfunction and to aid in determining appropriate treatment. The patient may complete a voiding and diary to provide a written record of the amount of urine voided and the frequency of voiding. Postvoid residual urine may be assessed either using straight catheterization or an ultrasound bladder scanner and is considered diagnostic of urinary retention if there is more than 100 mL of residual urine.