Calcium (Ca) in Urine

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A 24-hour calcium test in urine examines the concentration of calcium that is passed from the body. Calcium is the most common and important mineral in the body. The body needs it to build and fix bones and teeth, help nerves work, make muscles squeeze together, help blood clot, and help the heart to work. Almost all of the calcium in the body is stored in bone and in the blood.

Vitamin D and certain hormones, including parathyroid hormone, calcitonin, and estrogen help control the calcium levels. They also control the calcium absorbed from food and the calcium passed from the body in urine. The blood phosphate levels are closely corresponded to calcium levels and they work in opposite ways: as blood calcium levels increased, phosphate levels go low, and vice versa.

Usually the blood calcium levels are carefully controlled. When blood calcium level goes down (hypocalcemia), the bones release calcium to bring it back to a normal blood level. When blood calcium level goes up (hypercalcemia), the extra calcium is stored in the bones or passed out of the body in urine and stool. The amount of calcium in the body depends on the concentration of:
·Calcium taken from food.  
·Calcium and vitamin D that intestines absorbed.  
·Some hormones such as parathyroid hormone, calcitonin, and estrogen.  

At least 1 gram a day should be taken in the food because that is very important to get the right amount of calcium since the body loses calcium every day. Food products rich in calcium are milk, cheese, eggs, fish, green leafy vegetables, and fruit. Most people who have low or high levels of calcium do not have any symptoms. Too high or too low calcium levels cause symptoms.

High calcium levels in the urine can cause kidney stones.

Test results
A feedback loop involving Vitamin D and PTH regulates and stabilizes calcium absorption, excretion, and use. disorders that shatter the regulation of calcium level may cause improper acute or chronic elevations or decreases in calcium and lead to symptoms of hypercalcemia or hypocalcemia.
Usually, total calcium is examined since the test is more simply performed than the ionized calcium test and requires no especial handling of the blood sample. Total calcium is in most cases correctly reflects the free calcium because the free and bound forms are actually each about half of the total. Nevertheless, since about half the calcium in blood is bound to protein, total calcium test results can be affected by high or low levels of protein. So it is more helpful to measure free calcium directly using a test of ionized calcium.
An ionized calcium or normal total result in correspondence with other normal lab results generally means that your calcium metabolism is normal and blood levels are being appropriately regulated.
High Total Calcium - Hypercalcemia
There are two common causes of hypercalcemia:
·Hyperparathyroidism, an elevation in parathyroid gland function: This problem is usually caused by a benign tumor of the parathyroid gland. This form of hypercalcemia is commonly mild and can be persist for many years before being noticed.  
·Cancer: Cancer can cause hypercalcemia when it extends to the bones that releases calcium into the blood, or when a cancer produces a hormone similar to PTH, resulting in elevated calcium levels.  
Some other causes of hypercalcemia as following:
·Prolonged immobilization  
·Vitamin D intake  
·Kidney transplant  
Low Total Calcium - Hypocalcemia
A low blood level of the albumin protein is the most common cause of low calcium. In this case, only the bound calcium is low. The ionized calcium resides normal and calcium metabolism is being regulated appropriately.
Some other causes of hypocalcemia as following:
·Underactive parathyroid gland (hypoparathyroidism)  
·Inherited resistance to the effects of parathyroid hormone  
·Extreme deficiency in dietary calcium  
·Decreased levels of vitamin D  
·Magnesium deficiency  
·Increased levels of phosphorus  
·Acute inflammation of the pancreas (pancreatitis)  
·Renal failure  

Higher than normal levels may be due to:
·Addison's disorder  
·Excessive vitamin D level  
·Excessive calcium intake (also called milk-alkali syndrome)  
·Infections that cause granulomas such as tuberculosis and certain fungal and mycobacterial infections  
·Metastatic bone tumor  
·Milk-alkali syndrome  
·Multiple myeloma  
·Overactive thyroid gland (hyperthyroidism) or too much thyroid hormone replacement medication  
·Paget's disorder  
·Prolonged immobilization  
·Tumors producing a parathyroid hormone-like substance  
·Use of certain medications such as lithium, tamoxifen, and thiazides  
Drugs that can increase calcium levels include:
·Calcium salts (may be found in nutritional supplements or antacids)  
·Thiazide diuretics  
·Vitamin D  
Drinking too much milk (two or more quarts a day) or taking too much vitamin D as a dietary supplement can also increase blood calcium levels. It is very rare for high blood calcium to be due to cancer.

Lower than normal levels may be due to:
·Kidney failure  
·Liver disorder (decreased albumin production)  
·Magnesium deficiency  
·Malabsorption (inadequate absorption of nutrients from the intestinal tract)  
·Vitamin D deficiency  

Also you should know
Premature and low birth-weighted infants often are observed during the first few days of life for neonatal hypocalcemia by the ionized calcium test. This can happen since of an immature parathyroid gland and does not produce symptoms at all. The problem can resolve itself or can require treatment with supplemental calcium.
Blood and urine calcium examinations cannot tell how much calcium contains in the bones. An X-ray-like test, called a bone density or "Dexa" scan, is performed for this purpose.
Taking thiazide diuretic drugs is the most common medication induced reason for an increased calcium level.
Measuring total calcium is usually enough for screening proposes. The total calcium test is more simply performed than the ionized calcium test since it requires no especial handling of the blood sample. The ionized calcium test, by other words, requires special handling and expedited delivery of the blood sample to the lab for fast analysis. The necessary handling and delivery is difficult to achieve outside of a hospital setting. Usually, total calcium is a good substitute for free calcium since the free and bound forms are usually each about half of the total. The direct examination of ionized calcium is particularly important during surgery as well in extremely ill patients, when changes in total calcium do not tell for sure how abnormal the ionized calcium level is.
Milk foods are the main source of calcium, however lesser amounts are found in eggs, green vegetables, broccoli, legumes, nuts, and whole grains. Many fruit juices are now fortified with calcium.

All information on this page is intended for your general knowledge only and does not provide medical advice, diagnosis or treatment.