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 this 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?
Test results may vary depending on your age, gender, health history, and other things.
Your test results may be different depending on the lab used. They may not mean you
have a problem. Ask your healthcare provider what your test results mean for you.
Results of this test are given in milligrams per deciliter (mg/dL). A normal phosphorus
is between 3 and 4.5 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 is done with a blood sample. A needle is used to draw blood from a vein in
your arm or hand.
Does this test pose any risks?
Having a blood test with a needle carries some risks. These include bleeding, infection,
bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may
feel a slight sting or pain. Afterward, the site may be sore.
What might affect my test results?
Certain foods and drinks that are high in phosphorus can affect your test results.
Talk with your healthcare provider about your diet and how it might affect your test
results. A few examples of high phosphorus foods and drinks include:
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 directions. Be sure your healthcare 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.