Dr. Lani’s Directions for the 24-hour Urine Calcium Test
This test measures the amount of calcium in urine. All cells in the body require calcium in order to work. We need calcium for strong bones and teeth. Having enough calcium on board allow our heart to function, helps with muscle contraction, nerve signaling, and blood clotting.
Directions – no alcohol or calcium supplements for 48 hours before starting urine collection and light exercise only for 24 hours preceding the test and the 24 hours of the test day. If you are a female patient make sure they give you the collection container along with the storage container.
If you think your urine output will fill more that one container ask for two containers just in case.
You should try to collect every drop of urine during each 24-hour period. It does not matter how much or little urine is passed each time, as long as it is collected.
Directions Day one: Label the container with your name and date. It is best to keep the container capped in the refrigerator or a cool place.
IMPORTANT NOTES about collection: If you need to have a bowel movement, any urine passed with the bowel movement should be collected. Try not to include feces with the urine collection. If feces does get mixed in, do not try to remove the feces from the urine collection bottle.
If you need to urinate one hour before the final collection time, drink a full glass of water so that you can void again at the appropriate time. If you have to urinate 20 minutes before, try to hold the urine until the proper time.
Note the exact time of the final collection, even if it is not the same time as when collection began on day 1.
DOCTOR RECOMMENDATIONS FOR THIS TEST MAY VARY: The amount of time to stop calcium supplements can vary depending on what your doctor is trying to sort out. My first preferred first 24-hour urine test is to stop calcium supplements for 48 hours prior to testing. If urinary output of calcium is elevated then a second test is ordered and calcium supplementation is stopped for 7-10 days. I may run this test several times before I am satisfied with the results. If the patient consumes a lot of dairy I may also ask the patient to decrease the amount of dairy that they consume for the next test. Keep in mind that other lab tests are also important when assessing bone health. Additional lab testing may include: serum calcium, phosphorus, magnesium RBC, potassium, 25-hydroxy-vitamin D, 1,25 dihydroxy-vitamin D, PTH-intact with calcium, ionized calcium and bone markers and other tests depending on your individual needs.
Medications can interfere with test results.
Urine calcium levels can help your doctor:
If you are eating a normal diet, the expected amount of calcium in the urine is 100 to 250 mg/day.
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.
Note: mg/day = milligrams per day
High levels of urine calcium (above 300 mg/day) may be due to:
Low levels of urine calcium may be due to:
What you do not want to experience from your doctor: If your lab test comes back elevated and the doctor immediately assumes that you need a medication to treat the high urinary calcium output without additional testing is a red flag. What should happen is additional testing and further evaluation.
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