Calcium | Ca (24 hour urine)

Calcium homeostasis is maintained by parathyroid hormone. Most of the calcium is excreted in the feces, while a small amount of calcium is excreted in the urine, depending on the amount of calcium taken.

An increase in calcium in the urine is caused by an increase in intestinal absorption, a decrease in tubular reabsorption, calcium resorption or loss from the bones, and is almost always accompanied by an increase in blood calcium levels. When calcium is excreted in large amounts in the urine, it contributes to the development of nephrolithiasis and nephrocalcinosis, especially if it is associated with increased protein intake.

Determination of calcium in the urine is important for the diagnostics of hypercalcemia, which is responsible for the formation of kidney stones.

When to take a calcium test?

• Hypoparathyroidism;
• Rocket;
• Osteomalacia;
• Familial (benign) hypocalcemic hypercalcemia;
• Steatorrhea;
• Renal failure;
• Metastatic cancer of the prostate.

How to prepare for the test?

If urinary calcium is detected due to metabolic disease, the patient should follow a calcium-poor diet and should stop taking calcium-based medications 1-3 days before the test.

Study material / urine collection rule

24-hour urine. At 7 o'clock in the morning the patient urinates and does not store this urine, and during the next urination he collects the whole volume of urine in a plastic container (2-3 liter urine container) until 7 o'clock in the morning of the next day (24 hours); The patient should transfer 100 ml of urine from this container (e.g. with a syringe) to a disposable plastic cup for urine and should be stored at 2-8 ° C before the test (1-1,5 h).

Possible interpretation of the results

Increased concentration of calcium in the urine:

• Hyperparathyroidism (30-80% of cases);
• Calcium-rich diet;
• Excess intake of milk;
• Vitamin D poisoning;
• Sarcoidosis;
• Prolonged immobilization (especially in children);
• Multiple myeloma;
• Breast or bladder cancer;
• Osteoporosis (due to primary or secondary hyperthyroidism, Cushing's syndrome);
• Osteolytic lesions (carcinoma metastases, sarcomas);
• Paget's disease;
• Deformed osteitis;
• Renal tubular acidosis;
• Fanconi syndrome;
• Postvariectomy, estrogen deficiency,
• Idiopathic is hypercalcemic.

The concentration of calcium in the urine decreases:

• Hypoparathyroidism;
• Rocket;
• Osteomalacia;
• Vitamin D deficiency;
• Malabsorption syndrome;
• Acute nephrosis, nephritis, renal failure;
• Metastatic cancer of the prostate;
• Familial hypocalcemic hypercalcemia.

Resources

https://www.synevo.ro/shop/calciu-urinar/