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Company
Electrolytes
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Currently under review
Pending specialist review and validation.
This test measures the total amount of sodium your kidneys excrete in your urine over a full 24-hour collection period. Sodium is a key electrolyte that helps regulate fluid balance, blood pressure, and nerve and muscle function. Your body gets sodium mainly from food and drinks, and your kidneys adjust how much is kept or removed to maintain balance.
Because it captures an entire day, the test provides a more complete picture of your sodium intake and how your kidneys handle it than a single spot urine sample. You collect all urine for one day in a special container; the laboratory measures sodium and calculates how much you excrete in a day.
Clinicians use this test to estimate your dietary sodium intake and to assess how well your kidneys are regulating sodium. It can help guide treatment for conditions affected by salt and water balance, such as high blood pressure, heart failure, chronic kidney disease, and liver disease with fluid buildup. It may also be used when evaluating low or high sodium levels in the blood, or monitoring the effect of diuretics and sodium restriction.
Results can inform practical steps, like adjusting your diet, medications, or fluid management. The test itself is low risk, but accurate collection is important so your care team can make the best decisions about your treatment.
Your result is interpreted alongside your diet, medications, blood tests, urine volume, and medical conditions. A result higher than expected may reflect higher salt intake, certain medications, or reduced kidney reabsorption. A result lower than expected may reflect lower salt intake, volume depletion, or conditions that cause the body to retain sodium.
If the collection was incomplete or spilled, the result may not reflect your true daily excretion, and your clinician may ask you to repeat the test. Discuss your typical diet, fluid intake, and medication timing with your clinician, since small adjustments can meaningfully change the result. Together you can decide whether to repeat testing, make dietary changes, or adjust therapy.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Missing any urine during the 24-hour period, starting late, or ending early can falsely lower the measured sodium. Keep the container cool as instructed and return all collected urine to the lab promptly.
What you eat and drink strongly influences urinary sodium. High-salt meals, restaurant foods, and processed snacks raise excretion, while strict salt restriction lowers it. Try to follow your usual diet during collection unless told otherwise.
Diuretics, ACE inhibitors, ARBs, corticosteroids, and some herbal products alter kidney handling of sodium. Do not change or stop medicines on your own; ask your clinician if timing or temporary adjustments are needed.
Dehydration, vomiting, diarrhea, or aggressive fluid intake can change kidney sodium excretion. Let your clinician know if you were ill, overheated, or significantly changed your fluid intake during collection.
Heavy sweating from hot environments or intense exercise causes sodium loss through skin, which can reduce the amount appearing in urine. Try to collect on a typical day for you when possible.
Chronic kidney disease, heart failure, and cirrhosis affect hormones and blood flow that regulate sodium balance. Results are interpreted in the context of these conditions and other lab tests.
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