Blood phosphate level can be measured through a blood phosphate test. This test determines how much phosphate is present in your blood sample. The human body needs phosphorous for growth and repair of bones, muscles as well as teeth. It also makes the muscles contract and the nerves function. About 85 percent of the phosphorous in the human body is contained in the bones, while the remaining is spread in various tissues in the body.
Controlling phosphate levels in the blood is a function performed by the kidneys. If there is excess phosphate, this is filtered through the kidneys into the urinary tract and passes out as urine. Since the kidney controls phosphate levels, a high rate of phosphate in the blood is typically associated with a kidney problem.
It is also important to note that blood phosphate levels also have an effect on the calcium levels in your blood. Calcium and phosphate have an inverse relationship. So, if blood calcium levels increase, phosphate levels in the blood will fall and vice versa. However, in case of an infection or disease, this inverse relation can be disrupted. Therefore, most often phosphate and calcium are measured together.
Blood Phosphate Test Reasons
A blood phosphate test is ordered when a doctor wants to check if you have some kidney or bone disease. This test is also conducted to help detect problems in certain glands like the parathyroid gland.
There is no preparation for this test, apart from informing your doctor about any medication (prescribed or otherwise) you are taking.
Phosphate test procedure
In adults, this is a simple blood test, wherein blood sample is drawn from a vein in your arm. If the phosphate level of a newborn baby needs to be checked then a heel stick approach is used. In this procedure, blood sample is collected from the heel of your baby.
Phosphate test results
Results of a phosphate test are usually available in a couple of hours. Normal range of phosphate in blood for adults is 3 to 4.5 mg/dL (milligrams per deciliter). In children, phosphate levels are generally higher given bone growth and the normal range is 4.5 to 6.5 mg/dL and in infants the range is 4.3 to 9.3 mg/dL.
If your blood phosphate level is high this could be indicative of a kidney disease, bone disease, hypoparathyroidism, healing fractures, acromegaly and rhabdomylosis.
Other factors that can sometimes cause phosphate levels to rise include excess vitamin D, decrease in magnesium levels in the body and for women, pregnancy.
Low phosphate levels, on the other hand are indicative of hyperparathyroidism, osteomalacia, kidney and liver infections, lack of vitamin D and intense burns.
A few other factors that can cause low phosphate levels include alcohol abuse, severe malnutrition, increase in calcium levels as well as a condition like sprue, wherein the intestines are unable to absorb nutrients efficiently.
Low phosphate levels also affect those who have type 2 diabetes or if a diabetic person is treated with insulin. Studies indicate that children with low phosphate levels tend to grow slower than kids with normal phosphate levels.