What is a phosphate blood test?
A phosphate test measures the amount of phosphate in your blood. Your body needs this mineral to build and repair bones and teeth, help nerves function, and make muscles contract.
The kidneys help control the amount of phosphate in your blood. A high level of phosphate is usually caused by a kidney problem.
Why is a phosphate blood test done?
This test may be done to check phosphate levels if you have kidney disease or bone disease. It helps find problems with certain glands, such as the parathyroid glands. The test is also used to find a cause for abnormal vitamin D levels.
How is a phosphate blood test done?
Blood test
A health professional uses a needle to take a blood sample, usually from the arm.
Heel stick
A heel stick is used to get a blood sample from a baby. The baby's heel is poked, and several drops of blood are collected. A baby may have a tiny bruise where the heel was poked.
How do you prepare for a phosphate blood test?
Your doctor may ask you not to eat or drink anything other than water for at least 8 hours before the test.
What do the results of a phosphate blood test mean?
Normal
Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.
Phosphate levels are usually higher in children than in adults. That's because of the active bone growth occurring in children.
High values
High phosphate levels may be caused by:
- Some tumors such as lymphoma.
- Kidney disease, underactive parathyroid glands (hypoparathyroidism), acromegaly, untreated diabetic ketoacidosis, or certain bone diseases.
- Too much vitamin D in the body.
Low values
Low phosphate levels may be caused by:
- Hyperparathyroidism, certain bone diseases (such as osteomalacia), lack of vitamin D, or some kidney or liver diseases.
- Severe malnutrition or starvation.
- A condition such as sprue that prevents the intestines from absorbing nutrients properly.
- Alcohol use disorder.
- High calcium levels.
- Some types of tumors.
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