Does this test have other names?
Phosphorus blood test, phosphate test
What is this test?
This test measures the level of phosphorus in your blood. Phosphorus is a common mineral
found in the food you eat. It's also found in teeth and bones.
Having a high or low level of phosphorus in your bloodstream can signal a number of
health conditions. Most commonly, a high level of phosphorus is related to a kidney
disorder. It shows that your kidneys are having difficulty clearing phosphorus from
your blood. A high level of phosphorus can also mean uncontrolled diabetes and other
Why do I need this test?
You may need a phosphorus test if your healthcare provider suspects that you have
a kidney disorder. You may also need this test if you are having trouble controlling
your diabetes. You may need this test if you have symptoms of kidney disease, including
bone problems, fatigue, and weakness, but you may not have any symptoms at all.
What other tests might I have along with this test?
Phosphorus levels are closely related to calcium levels, so your healthcare provider will
probably test your calcium level as well. Additional tests depend on which condition
your healthcare provider suspects.
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses
to do the test. Even if your test results are different from the normal value, you
may not have a problem. To learn what the results mean for you, talk with your healthcare
Results of this test are given in milligrams per deciliter (mg/dL). A normal phosphorus
reading is between 2.7 and 4.6 mg/dL, but normal ranges may vary. A number that is
either higher or lower than that could mean a possible kidney problem.
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection,
bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight
stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
Phosphorus levels can be affected by what you eat and drink, including:
Many types of beans
Some medicines and medical procedures, such as dialysis, can also affect phosphorus
How do I get ready for this test?
You may need to fast starting at midnight before the test. Ask your healthcare provider
for specific instructions. Be sure your provider knows about all medicines, herbs,
vitamins, and supplements you are taking. This includes medicines that don't need
a prescription and any illicit drugs you may use.