Vesicoureteral Reflux (VUR) • Bladder and bowel

Voiding Diary, Uroflowmetry, and Biofeedback

Name: Voiding Diary, Uroflowmetry, and Biofeedback
Creator: Prof. Dr. Ali Avanoğlu
Published: 2026-08-19

The voiding diary, uroflowmetry (urine flow measurement), and residual urine measurement are simple, painless, radiation-free tools that show how the bladder is working. They are used in a child with vesicoureteral reflux (VUR) to reveal voiding dysfunction and to monitor response to treatment; biofeedback, in turn, is the specific way of correcting the problem found.

Who this is forFamilies of children for whom a voiding diary, uroflowmetry, or biofeedback has been recommended

Reading≈6 min

ByProf. Dr. Ali AvanoğluUpdated19 August 2026

This page is part of vesicoureteral reflux.Read the full treatment overview on the hub page

a full bowel presses on the bladder; with regular emptying the bladder fills easily

01 · How is a 48-hour voiding diary kept?02 · Uroflowmetry: what does the urine flow curve show?03 · Residual urine measurement 04 · How do biofeedback sessions proceed?

In brief4 madde

How is a 48-hour voiding diary kept?: The voiding diary is a record of how the bladder behaves in real life, and it is far more reliable than questions asked in the office.
Uroflowmetry: what does the urine flow curve show?: Uroflowmetry is a test in which the child voids into a special toilet or funnel, and the flow rate is recorded second by second.
Residual urine measurement: Measuring the urine remaining in the bladder by ultrasound right after voiding is the most direct indicator of complete emptying.
How do biofeedback sessions proceed?: Biofeedback is a specific urotherapy method that teaches the child to become aware of the pelvic floor muscles and to relax them during voiding.

How is a 48-hour voiding diary kept?

The voiding diary is a record of how the bladder behaves in real life, and it is far more reliable than questions asked in the office. The International Children's Continence Society (ICCS) recommends a record of at least 48 hours; the two days do not have to be consecutive, and two weekend days are usually chosen.

Two days (not necessarily consecutive), preferably non-school days
Every void: time, milliliters
Every drink: time, amount
Incontinence: time, degree of wetness, was there urgency?
Bowel movement: time, Bristol type
The child follows their usual routine; no changes are made to 'look good'

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A graduated container at home (a baby bottle or a kitchen measuring cup) is enough for recording. For every void, the time and amount are recorded; for every drink, the time and amount; if there is an accident, its time, degree (dampness, wetting the underwear, soaking through to outer clothing), and whether it was accompanied by urgency are also recorded. Bowel movement times and stool consistency (Bristol scale) are added to the same chart; if nighttime wetting is also being assessed, a separate 7–14 night wet–dry calendar is added to this.
From the diary, the daily number of voids, the largest voided volume (compared against the expected bladder capacity; in children, the rough expected capacity is calculated with the formula [age + 1] × 30 mL), the distribution of fluid intake, and the pattern of incontinence can all be read. The most common mistake families make is steering the child to 'behave well' during those two days; the value of the diary lies in reflecting the child's usual routine.

Uroflowmetry: what does the urine flow curve show?

Uroflowmetry is a test in which the child voids into a special toilet or funnel, and the flow rate is recorded second by second. There is no catheter and no radiation; all that is needed is for the child's bladder to be adequately full and for the child to be calm. Because a 'forced' void due to a small volume or unfamiliarity with the toilet setting can be misleading, two to three measurements are usually taken.

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The shape of the curve shows how well the bladder and outlet work together. A bell-shaped curve is normal. A tower-shaped curve — short and very high — suggests an overactive bladder. A staccato curve is a sign of dysfunctional voiding, in which the pelvic floor contracts during voiding. A fragmented-and-interrupted curve (flow dropping to zero and starting again) suggests an underactive bladder and straining to void, while a long, flat (plateau) curve raises the possibility of an outlet obstruction in the urinary tract, such as a stricture or valve.
In the same session, surface electrodes placed over the pelvic floor muscles (uroflow-EMG) can also show whether the muscles relax during voiding; this is the most practical way to confirm dysfunctional voiding. The curve alone does not make a diagnosis; it is interpreted together with the diary and the residual urine.

Residual urine measurement

Measuring the urine remaining in the bladder by ultrasound right after voiding is the most direct indicator of complete emptying. The measurement should be taken within the first few minutes after voiding; if it is delayed, new urine arriving from the kidneys raises the result.

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In children, a single high value does not make a diagnosis; the ICCS criteria use thresholds based on age and bladder capacity, and a significant amount of residual urine on repeated measurements (roughly above 20 mL, or about 10–20% of capacity) is considered 'incomplete emptying.' In a child with reflux, residual urine is measured repeatedly, both for infection risk and to monitor the response to urotherapy (voiding habit training).
The same ultrasound also assesses bladder wall thickness and rectal diameter; a thick wall is a sign of long-standing high pressure, and a widened rectum is a sign of constipation.

How do biofeedback sessions proceed?

Biofeedback is a specific urotherapy method that teaches the child to become aware of the pelvic floor muscles and to relax them during voiding. It is used in children who do not respond adequately to standard urotherapy and who continue to have a staccato curve and residual urine.

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During the session, surface electrodes attached around the hips transfer muscle activity to a screen; when the child relaxes, the game on the screen advances (a fish swims, a plane descends), and when the muscle contracts, it stops. In this way, the child learns to control an invisible muscle through play. Sessions are usually planned once a week or every two weeks, 30–45 minutes each, for a total of 6–10 sessions; at the end of each session, progress is checked with uroflow-EMG, and relaxation-and-sitting exercises to practice at home are given.
The literature reports that, with biofeedback, the curve normalizes, residual urine decreases, and urinary tract infection recurrence drops in a large proportion of children with dysfunctional voiding; there are also case series in which reflux regressed in children who had reflux at the same time. It can be applied in any child from about five or six years of age who understands the game and cooperates with it. In our practice, this evaluation and these sessions are planned under the supervision of the same pediatric urology team that carries out the reflux follow-up.

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Frequently asked questions

Is special preparation needed for uroflowmetry?

No heavy preparation is needed. It is enough for the child to drink water 1–2 hours before the test and hold their urine, arriving with the bladder full enough to feel the urge but not uncomfortable. Because residual urine is checked with ultrasound right after the measurement, the void is done immediately before that.

Do we have to measure the amounts on the voiding diary?

Yes; the largest voided volume and the distribution throughout the day can only be seen through measurement. A graduated container or a kitchen measuring cup is enough. If measurement is not possible at school, only the time is recorded; choosing two weekend days largely solves this problem.

Does biofeedback hurt, and will my child be afraid?

It is painless; the electrodes are attached to the skin, and nothing enters the body. Children mostly experience the sessions as a game. The challenge is for the child to understand the instructions and to attend regularly; this is why it is generally planned for school age.

Do these tests replace the VCUG (voiding cystourethrogram)?

No. Uroflowmetry and residual urine show how the bladder is working, while the VCUG shows the presence and grade of reflux. They are complementary tests, not substitutes for one another; in a child with reflux, bladder assessment shapes the treatment decision.

Prof. Dr. Ali Avanoğlu's publications on this topic · 2

Tiryaki S, Tekin A, Avanoglu A, et al. (2022). A pilot study assessing average detrusor pressure garnered from area under a urodynamic curve: Evaluation of clinical outcomes. Journal of pediatric urology. PubMed ↗
Sözübir S, Celik A, Emir N, et al. (2005). Consistency of urodynamic parameters in children with detrusor instability: how many times should the bladder be filled? Urologia internationalis. PubMed ↗

←Previous • Bladder and bowelVoiding Dysfunction, Urgency, Urinary Incontinence, and VUR

Related pagesFull index →

Bladder and bowelUrotherapy: Timed Voiding, Fluids, and Toilet HabitsUrotherapy is a drug-free, non-invasive education program that teaches the child to empty the bladder at the right time, in the right way, and completely. It is the first step of treatment in a child with vesicoureteral reflux (VUR) who also has voiding dysfunction or constipation, and it begins to show its effect within weeks.Bladder and bowelVoiding Dysfunction, Urgency, Urinary Incontinence, and VURDaytime urinary incontinence, sudden urgency, and holding maneuvers are the most visible signs of voiding dysfunction in children. In a child with vesicoureteral reflux (VUR), these symptoms are not merely a social problem: high pressure and residual urine in the bladder feed infection and the persistence of reflux. This page explains the difference between 'urinary incontinence' and 'urine backflow (reflux)', and the treatment approach.Bladder and bowelWhat Is Bladder-Bowel Dysfunction (BBD), and How Does It Affect Reflux?Bladder-bowel dysfunction (BBD) is a condition in toilet-trained children in which voiding problems are intertwined with constipation. In children with vesicoureteral reflux (VUR), BBD both increases the recurrence of urinary tract infections and delays the resolution of reflux; for this reason, it is screened for and treated before deciding on reflux treatment.Bladder and bowelDoes Constipation Cause Urinary Tract Infection and Reflux?Constipation is one of the most commonly overlooked causes of urinary tract infection in children, and in a child with vesicoureteral reflux (VUR), it increases infection recurrence and delays the resolution of reflux. This page explains how constipation is recognized, how it affects the bladder, and how it is treated.

Vesicoureteral Reflux (VUR) topic clustersMain treatment page →

Basics 6 Diagnosis and evaluation 6 By age and special situations 5 Bladder and bowel 5 Treatment pathways 10 Kidney health and infection 5 After treatment and follow-up 6

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