|ID:144 ||Osmolality (urine)||Search Links: General Info : Protocols : Patient Info|
|Description||A measure of urine tonicity / concentration|
|Indication||Investigation of polyuria.
|Additional Info||Primary polydipsia can cause a low urine osmolality and should be considered as a cause particularly in psychiatric patients. Primary polydipsia will be associated with a dilutional hyponatraemia. With primary polydipsia urine may remain dilute even with fluid restriction but serum osmolality is often low or low to normal. A prolonged water deprivation test may be required.
|Interpretation||A urine osmo >750 mOsmol/Kg excludes DI as a cause of polyuria (in classic DI serum osmolality increases >300 and urine osmolality remains <350 mOsmol/Kg). However, a low urine osmolality is NOT diagnostic of DI.
|Ref. Range (Male)|| |
|Ref. Range (Female)|| |
|Ref. Range (Paed)|| |
|Ref. Range Notes||
|IP Acute TAT||Refer to Website|
|IP Routine TAT||Refer to Website|
|GP Acute TAT||- Contact Laboratory|
|GP Routine TAT||Refer to Website|
|Turnround Comment||Osmolality analysis will only be treated as urgent if the lab is contacted, and in such instances will have a TAT of 3hrs|
Originally edited by : JHB. Last edited on 10/04/2019 14:13:20. Published By S.Bennett on 10/04/2018 14:13:20.