OVERVIEW:
What is the fraction sodium excretion lab test?
A fraction sodium excretion lab test is more of a calculation than a test. Fractional excretion of sodium is the amount of salt that is excreted in the urine compared to the amount filtered and reabsorbed by the kidneys.
Why is the fraction sodium excretion lab test done?
A fraction sodium excretion lab test is done in order to:
- Detect kidney damage,
- Monitor patients with acute kidney disease,
Identify the cause behind reduced urine production.
What does a fraction sodium excretion lab test measure?
A fraction sodium excretion lab test measures the amount of sodium excreted in the urine and compares it with the amount of sodium that is filtered and reabsorbed by the kidneys. Fractional excretion of sodium lab test depends on the concentration of sodium and creatinine in urine and blood.
Are there any risks associated with this test?
There are no known risks associated with this test.
How should I prepare for this test?
Your doctor may ask you to stop taking certain medicines such as diuretics before the test.
What does a high fraction sodium excretion mean?
A high fraction sodium excretion suggests kidney damage.
What are the causes behind a low fractional sodium excretion?
Low fraction sodium excretion is caused by reduced blood flow to the kidneys. This could be due to dehydration or heart failure.
What medications affect fractional excretion of sodium?
Diuretics, dopamine, and norepinephrine affect fractional sodium excretion.
Fraction excretion of sodium less than 1% indicates reduced blood flow to the kidneys.
Fraction excretion of sodium greater than 1% indicates damage to the kidneys.
A fraction sodium excretion lab test is done in order to:
- Detect kidney damage,
- Monitor patients with acute kidney disease,
- Identify the cause behind reduced urine production.