The phosphorus blood test measures the amount of phosphate in the blood.
A blood sample is needed.
Your health care provider may tell you to temporarily stop taking medicines that may affect the test. These medicines include water pills (diuretics), antacids, and laxatives.
DO NOT stop taking any medicine before talking to your provider.
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.
Phosphorus is a mineral the body needs to build strong bones and teeth. It is also important for nerve signaling and muscle contraction.
This test is ordered to see how much phosphorus is in your blood. Kidney, liver, and certain bone diseases can cause abnormal phosphorus levels.
Normal values range from:
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.
A higher than normal level (hyperphosphatemia) may be due to many different health conditions. Common causes include:
A lower than normal level (hypophosphatemia) may be due to:
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.