What is a bladder diary and why does a urologist ask for one?
A bladder diary (frequency–volume chart) is a simple table in which you record, hour by hour, how much you drink, how often and how much urine you pass, and any urgency or leakage. The European Association of Urology (EAU) guidelines recommend a diary of at least three days for men with frequency, urgency or getting up at night to pass urine (nocturia), and for women with urinary incontinence. The NICE guidelines in the UK also ask for this chart at the initial assessment.
The diary replaces guesses based on memory with real figures. It helps to tell whether the problem comes from a bladder that holds only small amounts, from drinking a lot, or from producing too much urine at night. The same chart can be used again later to see how well treatment is working.
How do I fill in a bladder diary?
- Choose three days, ideally one working day and one day off; they do not have to be consecutive.
- Each day starts when you get up and ends when you get up the next morning. Do not record the first urine on the first morning; write the first urine of the following morning on the last line of that day as “First urine next morning”.
- Pass urine into a jug marked in millilitres and write down the amount. If you miss one, write an estimate.
- Write down everything you drink with its type and amount: water, tea, coffee, juice, soup, alcohol. A glass is about 200 ml and a mug about 250 ml.
- Rate the urgency from 0 to 3. If you leak, note the amount, what you were doing at the time (coughing, standing up, on the way home) and whether you changed a pad.
- Write down when you went to bed to sleep and when you got up; mark each void after waking at night as “Night”.
- Do not change your habits during these days: the aim is to see an ordinary day.
How are bladder diary results interpreted?
For each day, the on-screen summary calculates fluid intake, daytime and night-time voids, total and average voided volume, the largest single void and the night-time share of urine. These figures do not make a diagnosis on their own, but they are a useful guide when interpreted with your urologist:
- 24-hour urine volume: The International Continence Society (ICS) defines a daily urine output above 40 ml per kilogram of body weight as excessive urine production (polyuria); for a person weighing 70 kg this is about 2.8 litres.
- Largest voided volume: The largest single void of the day gives an idea of the bladder’s functional capacity. Passing small amounts frequently all the time may suggest an overactive or irritated bladder.
- Nocturnal polyuria index: This is the share of the 24-hour urine produced at night (including the first urine in the morning). According to the ICS, a value above 33% in people over 65, or above 20% in young adults, suggests excessive night-time urine production. The assessment then also looks at evening drinking, heart and kidney function, sleep apnoea and medicines, not only the bladder.
- Night-time voids: Waking from sleep to pass urine is called nocturia. Getting up twice or more often noticeably affects sleep quality and daytime energy.
When should I bring the diary to a urologist?
Fill in the diary in the days before your appointment. If you used the on-screen version, print it with “Print my entries”, or bring the paper form with you. The diary is particularly helpful for frequency, getting up at night, sudden urgency, leakage, monitoring treatment for an enlarged prostate and check-ups after surgery. If you have prostate symptoms, completing the IPSS questionnaire as well makes the consultation easier.
If you have blood in your urine, burning with fever, cannot pass urine or have severe pain in your side, see a doctor without waiting to finish the diary.