What is osmolality?
Osmolality is the concentration of particles in a fluid.
What is this test?
Urine osmolality test is a laboratory test to measure the concentration of particles in the urine. It determines electrolyte balance in the body and functioning of the kidneys. Sodium and glucose commonly affect blood osmolality.
Why is this test performed?
- This test is ordered by the doctor if the patient is experiencing:
- High blood sodium
- Increased urination
- Increased thirst
- Chronic diarrhea
- Dehydration
- Nausea
- Seizures.
- To determine kidney function
- To determine electrolyte balance
- If the doctor suspects poisoning
- If the doctor suspects diabetes insipidus.
- How to take the sample?
- Clean your hands and genitals
- Pour mid-stream urine in a sterile container
- Avoid contact of container with genitals
- Wash your hands properly.
- What will affect my test results?
Rich-protein diet before the test may affect the results. Proteins can increase the osmolality.
- Can I drink water before the test?
Excess water consumption might lower the osmolality levels. Your doctor may ask you to restrict fluids before the test.
- Is this test used to detect alcohol poisoning?
Yes, this test is also used to detect alcohol poisoning.
- What medicines can affect the test results?
Medicines, such as dextran and sucrose can affect the results of urine osmolality test.
Normal range:
500-850 mOsm/kg
- Interpretation of test results:
Causes of increased osmolality:
- Congestive heart failure
- Glycosuria
- Dehydration
- Kidney injury
- Adrenal problems
Causes of decreased osmolality:
- Kidney failure
- Diabetes insipidus
- Over-hydration.