Urine Calcium
- Sample Type
- Urine (24h)
- Fasting
- No
- Unit
- mg/24h
Function
Urine calcium measures the amount of calcium excreted by the kidneys over a 24-hour period. Calcium is vital for bone health, nerve transmission, and muscle function. The body maintains blood calcium levels within a very tight range; the kidneys play a primary role in this by filtering calcium and either reabsorbing it into the blood or excreting the excess into the urine.
Why it is Ordered
The test is most frequently used to evaluate patients with recurrent kidney stones (nephrolithiasis), as high urine calcium is a major risk factor for stone formation. It is also used to diagnose parathyroid gland disorders, monitor the effects of Vitamin D supplementation, and investigate the causes of abnormal blood calcium levels. It helps clinicians distinguish between intestinal over-absorption of calcium and renal 'leaking' of calcium.
Associated Conditions
- Hyperparathyroidism: Overactive parathyroid glands pull calcium from bones into the blood, leading to high urine excretion.
- Sarcoidosis: An inflammatory disease that can increase Vitamin D sensitivity and calcium levels.
- Renal Tubular Acidosis: A kidney condition that causes calcium to leach into the urine.
- Osteoporosis: High urine calcium can sometimes indicate rapid bone loss.
- Hypoparathyroidism: Results in low blood and urine calcium levels.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
Urine calcium is extremely sensitive to dietary intake. A single day of high salt (sodium) or high protein intake can significantly increase calcium excretion. Conversely, thiazide diuretics reduce urine calcium. If the 24-hour collection is incomplete (missing even one void), the results will be inaccurately low. Accuracy should be verified against a 'Urine Creatinine' to ensure the collection was full.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Urine Calcium:
Official Sources
Research & Guidelines
- PubMed: Urine Calcium Clinical GuidelinesNCBI / PubMed
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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