Serum/plasma concentration of fluoxetine (antidepressant medication)
This test measures the amount of fluoxetine, a prescription antidepressant, in your blood. It helps doctors check if your dose is working properly or if adjustments are needed.
["This test helps monitor your antidepressant treatment effectiveness and safety."]
Key facts at a glance
- LOINC
- 73374-1
- Short code
- FLUoxetine ind plt IgM SerPl Ql FC
- Synonyms
- FLUoxetine ind plt IgM SerPl Ql FC
- Category
- hematology
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- flow-cytometry
- CPT
- 82784
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order this test if you’re taking fluoxetine (Prozac, Sarafem, others) to ensure the medication is at an appropriate level in your blood. It’s also used to detect drug interactions or to adjust your dose based on how your body processes the medication.
What to Expect Before the Test
No special preparation is needed. You may have a simple blood draw from a vein in your arm. If you’re taking fluoxetine, it’s best to check with your doctor before the test to ensure no timing conflicts (e.g., if your dose is taken at a specific time).
What Happens During the Test?
A healthcare professional will clean your arm, insert a small needle into a vein, and collect a blood sample. The sample is then sent to a lab for testing. The process usually takes a few minutes.
What Are the Results Meant to Tell You?
Results provide a quantitative measure of fluoxetine concentration in your blood. This helps your doctor assess whether your dose is therapeutic (effective) or if you may be experiencing side effects. Results aren’t interpreted alone but in relation to your symptoms and medical history.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
High or low fluoxetine levels can indicate issues such as inadequate dosing (leading to poor symptom control), toxicity (if levels are dangerously elevated), or drug interactions (e.g., with other medications metabolized by the same liver enzymes). Regular monitoring helps balance effectiveness and safety.
Short name
Fluoxetine Level
Frequently asked questions
How often should I expect this test?
What if I miss my fluoxetine dose before the test?
Can I drink alcohol before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy