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Home > Patient & Family Resources > Health Library > Medicine Levels in Blood
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A medicine blood level test measures how much of your medicine is in your blood. Your doctor checks it to make sure that you are taking a safe and effective dose. This testing is also called therapeutic drug monitoring.
This information is about medicines that are not used to control seizures. To learn about testing seizure medicine levels, see Seizure Medicine Levels in Blood.
Certain types of medicine need to be monitored because:
Your doctor may use your test results to adjust your dose.
You may need testing when you take medicines such as:
Depending on the kind of medicine you take, your doctor may schedule your test at a certain time of day. For example, you may have your test in the morning, before you take your medicine. Or your test might be after you take your medicine.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form .
The health professional who takes a sample of your blood will:
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
There is very little chance of a problem from having a blood sample taken from a vein.
A medicine blood level test measures how much of your medicine is in your blood. Your doctor checks it to make sure that you're taking a safe and effective dose. This testing is also called therapeutic drug monitoring.
Your doctor or test results may mention a "therapeutic range" for your medicine. The range for "normal" varies from lab to lab. Your lab report should show what range your lab uses for "normal." Also, your doctor will evaluate your results based on your health and other factors. So a number that is outside the normal range may still be normal for you.
Your test results can be affected by:
Current as of: December 9, 2019
Author: Healthwise StaffMedical Review: Kathleen Romito, MD - Family MedicineAdam Husney, MD - Family MedicineMartin J. Gabica, MD - Family MedicineE. Gregory Thompson, MD - Internal Medicine
Current as of: December 9, 2019
Author: Healthwise Staff
Medical Review:Kathleen Romito, MD - Family Medicine & Adam Husney, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine
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