What’s the name of the blood test that measures the level of antidepressant you have?

As for as a blood test is concerned: "Researchers discovered that a blood test measuring a patient’s C-reactive protein (CRP) levels through a simple finger-prick blood test can help doctors prescribe a medication that is more likely to work. Utilizing this test in clinical visits could lead to a significant boost in the success rate of depressed patients who commonly struggle to find effective treatments."

More common (and which does not require a blood draw) is: "Your doctor may use cytochrome P450 (CYP450) tests to help determine how your body processes (metabolizes) a drug. The human body uses cytochrome P450 enzymes to process medications. Because of inherited (genetic) traits that cause variations in these enzymes, medications may affect each person differently.

Drug-gene testing — also called pharmacogenomics or pharmacogenetics — is the study of how genes affect your body's response to medication. Tests look for changes or variations in these genes that determine whether a medication could be an effective treatment for you or whether you could have side effects from a specific medication.

The cytochrome P450 enzyme includes the CYP2D6 enzyme, which processes many antidepressants and antipsychotic medications. By checking your DNA for certain gene variations, CYP450 tests can offer clues about how your body may respond to a particular antidepressant. CYP450 tests can also identify variations in other enzymes, such as the CYP2C19 enzyme."

All the best and take care for now.