What is the role of urinary calcium, creatinine and uric acid testing in the workup of hypercalciuria?

Updated: Apr 23, 2019
  • Author: Stephen W Leslie, MD, FACS; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Not only does this study function as a reasonable screening test to document hypercalciuria, it also reveals hyperuricosuria. The calcium/creatinine and uric acid/creatinine ratios should be calculated to determine whether or not abnormalities are present. The normal calcium/creatinine ratio is less than 0.2; if the calculated ratio is higher than 0.2, repeat testing is indicated. If the follow-up results are normal, then no additional testing for hypercalciuria is needed. On the other hand, if the ratio remains elevated, a timed 24-hour urine collection should be obtained and the calcium excretion calculated.

The 24-hour calcium excretion test is the criterion standard for the diagnosis of hypercalciuria. If the calcium excretion is higher than 4 mg/kg/day, the diagnosis of hypercalciuria is confirmed and further evaluation is warranted.

Similarly, if hyperuricosuria is detected (through the uric acid ̶ to-creatinine ratio), the appropriate evaluation for this condition should be initiated.


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