This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages without signing in


Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Urine is produced by the kidneys. The volume of urine produced depends on fluid intake and diet. A typical urinary volume is between 0.8 and 2.6 L per day.

The kidneys maintain electrolyte balance by excreting excess electrolytes into the urine. The waste-products of nitrogen metabolism are removed by the excretion of urea. In order to maintain homeostasis the kidneys must produce a minimum volume of urine per day. This volume is determined by the concentrating power of the kidneys and the amount of solute to be excreted. An average Western diet requires the excretion about 800 mosmol of solute daily. The maximum concentration of solute in the urine is around 1200 mosmols therefore there is a minimum daily urine volume of approximately 650 ml.

Polyuria, oliguria and anuria are description of the volume of urine produced:

  • polyuria:
    • is the production of an excessive volume of urine per day
    • often accompanied by nocturia and frequency
    • should be distinguished from urinary frequency

  • oliguria is the production of less than 300 ml of urine per day

  • anuria exists when there is no urinary output

With urinary tract infections the urine may become cloudy and smell fishy. Certain foods (eg. beetroot) and drugs (eg sulphasalazine) may colour the urine. In porphyria the urine turns red/browm on standing.

Related pages

Create an account to add page annotations

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.