Fluoxetine Test
Short Name: Fluoxetine TDM
Also known as: Fluoxetine Level Test, Prozac Level Test, SSRI Drug Level Test, Fluoxetine and Norfluoxetine Assay, Fluoxetine Therapeutic Drug Monitoring
Fluoxetine Test test available at DNA Labs India for ₹15,000. Uses LC-MS/MS (Liquid Chromatography-Tandem Mass Spectrometry) on Serum samples. Results in Results are typically available within 2-3 weeks after sample collection. Samples should be submitted by the 7th of the month for timely processing. Reports are delivered via the DNA Labs India online portal, email, and WhatsApp.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr Ramarao Paidisetty
Consultant Biochemist · Reg: 21504
Last reviewed: September 7, 2026
Overview
The Fluoxetine Test is prescribed to: 1. Monitor serum concentrations of fluoxetine and its active metabolite norfluoxetine to ensure therapeutic drug levels are maintained. 2. Evaluate potential drug toxicity in patients exhibiting adverse effects such as serotonin syndrome symptoms, cardiac arrhythmias, or CNS disturbances. 3. Assess patient compliance with the prescribed fluoxetine regimen, especially in cases of suspected non-adherence. 4. Guide dose adjustments in patients with inadequate therapeutic response despite standard dosing. 5. Identify drug-drug interaction effects in patients taking multiple medications that may alter fluoxetine metabolism (e.g., CYP2D6 inhibitors). 6. Support clinical decision-making in patients with hepatic or renal impairment where drug clearance may be compromised.
- Test Code
- 627
- Price
- ₹15,000
- Sample Type
- Serum
- Result Time
- Results are typically available within 2-3 weeks after sample collection. Samples should be submitted by the 7th of the month for timely processing. Reports are delivered via the DNA Labs India online portal, email, and WhatsApp.
- Fasting Required
- No
- Method
- LC-MS/MS (Liquid Chromatography-Tandem Mass Spectrometry)
Sample Collection
Duly filled Test Send Out Consent Form (Form 35) is mandatory. Ideal sampling time is >12 hours post oral dose (trough level). Inform your doctor about all medications, supplements, and herbal products you are currently taking. No specific fasting is required, but timing relative to the last dose is critical for accurate trough-level measurement.
Method: Venipuncture
Laboratory Analysis
A blood sample of 3 mL (minimum 1.5 mL) will be drawn via venipuncture from a vein in your arm. The sample is collected in a Red Top (no additive) tube. SST gel barrier tubes must not be used. The procedure typically takes 5–10 minutes and may cause minor discomfort.
Report Delivery
After sample collection, gentle pressure is applied to the puncture site with cotton wool. A small bandage is placed over the site. The sample is processed and shipped refrigerated or frozen to the reference laboratory for LC-MS/MS analysis. You may resume normal activities immediately after sample collection.
Timeline: Results are typically available within 2-3 weeks after sample collection. Samples should be submitted by the 7th of the month for timely processing. Reports are delivered via the DNA Labs India online portal, email, and WhatsApp.
Patient Instructions
About This Test
Who Should Get This Test
The Fluoxetine Test is prescribed to:
1. Monitor serum concentrations of fluoxetine and its active metabolite norfluoxetine to ensure therapeutic drug levels are maintained.
2. Evaluate potential drug toxicity in patients exhibiting adverse effects such as serotonin syndrome symptoms, cardiac arrhythmias, or CNS disturbances.
3. Assess patient compliance with the prescribed fluoxetine regimen, especially in cases of suspected non-adherence.
4. Guide dose adjustments in patients with inadequate therapeutic response despite standard dosing.
5. Identify drug-drug interaction effects in patients taking multiple medications that may alter fluoxetine metabolism (e.g., CYP2D6 inhibitors).
6. Support clinical decision-making in patients with hepatic or renal impairment where drug clearance may be compromised.
How to Prepare
- Collect sample in a Red Top (No Additive) tube only. Do NOT use SST gel barrier tubes.
- Minimum sample volume: 1.5 mL serum from 3 mL whole blood.
- Ideal sampling time: >12 hours after the last oral dose of fluoxetine (trough level).
- Sample stability at Room Temperature: up to 8 hours.
- Sample stability when Refrigerated (2-8°C): up to 5 days.
- Sample stability when Frozen (-20°C): up to 30 days.
- Ship sample refrigerated or frozen to the testing laboratory.
- Duly filled Test Send Out Consent Form (Form 35) is mandatory with every sample.
- Submit sample by the 7th of the month for report delivery within 2-3 weeks.
Doctor's Notes
Reviewed by Dr Ramarao Paidisetty — MBBS, MD (Biochemistry) · Reg. No. 21504
"Monitoring fluoxetine serum levels is essential for optimising treatment outcomes in patients on SSRI therapy. This test helps confirm adequate drug absorption, identify sub-therapeutic levels that may explain treatment failure, detect potential toxicity, and verify patient compliance. Measuring both fluoxetine and its active metabolite norfluoxetine provides a comprehensive picture of overall drug exposure. This is especially valuable in patients with hepatic impairment, those on polypharmacy involving CYP2D6 or CYP3A4 inhibitors, elderly patients, and individuals with suspected non-adherence to their medication regimen."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Sample collected in SST gel barrier tube
- Sample collected less than 12 hours post oral dose without clinical justification
- Missing or incomplete Test Send Out Consent Form (Form 35)
- Hemolyzed, lipemic, or contaminated serum samples
- Insufficient sample volume (less than 1.5 mL serum)
- Sample stored at room temperature for more than 8 hours
- Unlabelled or mislabelled sample tubes
Understanding Your Results
Sub-therapeutic fluoxetine levels may indicate poor drug absorption, non-compliance with prescribed medication, rapid drug metabolism (ultra-rapid CYP2D6 metabolisers), or inadequate dosing. Clinical correlation is essential, and your psychiatrist may consider dose adjustment or formulation change.
Status: Below Therapeutic Range
Range: Fluoxetine below 100 ng/mL
Fluoxetine levels are within the expected therapeutic range, suggesting adequate drug exposure for clinical effect. Continue medication as prescribed by your psychiatrist. Regular follow-up and periodic monitoring are recommended to ensure sustained therapeutic benefit.
Status: Within Therapeutic Range
Range: Fluoxetine 100 – 500 ng/mL
Elevated fluoxetine levels may increase the risk of adverse effects including serotonin syndrome (agitation, hyperthermia, tachycardia, muscle rigidity), QT interval prolongation, CNS toxicity, and gastrointestinal disturbances. Consult your psychiatrist immediately. Dose reduction or drug discontinuation may be necessary depending on clinical context.
Status: Above Therapeutic Range
Range: Fluoxetine above 800 ng/mL
Elevated combined levels of fluoxetine and norfluoxetine suggest significant drug accumulation, which may occur in patients with hepatic impairment, poor metaboliser status (CYP2D6), or drug interactions inhibiting metabolism. Clinical review and potential dose adjustment are recommended.
Status: Elevated Combined Levels
Range: Norfluoxetine above 500 ng/mL with elevated fluoxetine
Consult your psychiatrist or healthcare provider if your fluoxetine levels are outside the therapeutic range, if you experience worsening symptoms of depression or anxiety, signs of serotonin syndrome (agitation, hallucinations, rapid heartbeat, fever, muscle stiffness), unexplained bleeding, significant changes in appetite or sleep, suicidal thoughts, or if you have any concerns about medication side effects. Seek emergency medical attention immediately if you experience chest pain, severe dizziness, seizures, or allergic reactions.
Limitations
- ⚠This is a send-out test; results require 2-3 weeks from the date of sample collection
- ⚠Reference ranges are general guidelines; individual therapeutic targets may vary based on clinical indication and patient factors
- ⚠Results should always be interpreted in conjunction with clinical presentation and not used in isolation for treatment decisions
- ⚠Cross-reactivity with structurally similar compounds is minimised by LC-MS/MS but cannot be entirely excluded
- ⚠Trough level sampling (>12 hours post dose) is critical for accurate interpretation; non-trough samples may yield elevated results
Risks & Considerations
- ●Minor bruising or discomfort at the venipuncture site
- ●Slight risk of infection at the blood draw site
- ●Rare possibility of fainting or dizziness during or after blood collection
- ●Minimal bleeding risk, particularly in individuals on anticoagulant therapy
Interfering Factors
- ●Concurrent use of other SSRIs or serotonergic medications may affect interpretation
- ●CYP2D6 inhibitors (e.g., paroxetine, fluvoxamine, quinidine) can elevate fluoxetine levels
- ●CYP3A4 inhibitors (e.g., ketoconazole, erythromycin) may alter drug metabolism
- ●Herbal supplements such as St. John's Wort may lower fluoxetine levels through enzyme induction
- ●Severe hepatic impairment can significantly alter fluoxetine and norfluoxetine clearance
- ●Use of SST gel barrier tubes for sample collection may interfere with assay results
Compare With Similar Tests
| Test | Fluoxetine Test | Sertraline Test | Escitalopram Test | Paroxetine Test |
|---|---|---|---|---|
| Comparison | Fluoxetine Test |
Frequently Asked Questions
What is the Fluoxetine Test?
Why is the Fluoxetine Test prescribed by doctors?
What is the cost of the Fluoxetine Test in India?
How is the blood sample collected for the Fluoxetine Test?
What is the ideal sampling time for the Fluoxetine Test?
Is fasting required before the Fluoxetine Test?
How long does it take to receive the Fluoxetine Test report?
What are the normal therapeutic levels of Fluoxetine?
What does a high fluoxetine level indicate?
Can other medications affect the Fluoxetine Test results?
Do I need a doctor's prescription for the Fluoxetine Test?
Is home sample collection available for the Fluoxetine Test across India?
Related Tests
Reference Laboratory Services
We serve as a reference laboratory for hospitals and clinics across India. Send samples from your facility with same-day pickup, priority processing, and results delivered through our online portal. Competitive institutional pricing available.
Your Data Privacy
Your medical data is protected under Indian law.
✓ Stored in India: All patient records are stored on servers located in India. No data is transferred outside the country.
✓ DPDP Act Compliant: Under the Digital Personal Data Protection Act 2023, you can request deletion of your records at any time by contacting support.
Book Your Test
Enter your details and we'll connect you within 15 minutes.