An above normal increase in urination is termed polyuria. It is generally accepted that a urine output above 3L/day denotes polyuria. This increased output can be the result of an inability to concentrate urine or an increase is solute excretion.
Polyuria is associated with the following conditions:
- A 24hr measurement of urine output and osmolality can be used to confirm the presence of polyuria. Urinalysis for glucose as well as measurement of solute excretion rate can help to differentiate the underlying cause of polyuria.
- Relevant imaging may be necessary to identify the underlying cause of polyuria, including MRI. 
It is important to identify the underlying mechanism resulting in polyuria, and treatment protocols should be specific to each pathology.
Reviewed by Iva Lloyd, BScH, RPE, ND 
- Skorecki K, Ausiello D (2011) Goldman:Goldman's Cecil Medicine 24th ed Chap 118 Disorders of Sodium and Water Homeostasis Saunders
- Ferri J (2011) Ferri's Clinical Advisor 1st ed Section P-Polyuria Mosby
- Verbalis JG (2011) Taal: Brenner and Retor's The Kidney 9th ed Chap 15 Disorders of Water Balance Saunders