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Ondansetron (Serum) Concentration

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of ondansetron, a medication used to prevent nausea and vomiting, in your blood. It may be checked if you’re taking this drug or experiencing side effects.

Quick summary

["Ondansetron helps manage nausea but can sometimes cause its own symptoms—this test helps track your body’s response."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
89452-7
Short code
Ob NP Note
Synonyms
Ob NP Note
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
100
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
obstetrics-nurse-practitioner
CPT
83880
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 This Test Is Done

Your doctor may order this test if you’re taking ondansetron for chemotherapy, surgery, or other treatments that cause nausea. It could also be done if you’re experiencing unusual side effects like dizziness, fatigue, or irregular heartbeat, which could indicate a drug level that’s too high or too low.

What to Expect Before the Test

No special preparation is needed. A blood sample is taken from a vein in your arm. You may feel a slight pinch, but it’s quick and usually not painful. If you’re on ondansetron, let your healthcare provider know before the test.

What the Results Mean

Results help determine if your ondansetron levels are within the safe range. Too much can cause side effects, while too little may mean the drug isn’t working as intended. Your doctor will discuss these results with you.

Possible Side Effects

Ondansetron is generally safe, but high levels can sometimes cause dizziness, headache, or rare but serious heart problems. If you notice these symptoms after taking the drug, contact your doctor.

Reference range

Normal: <100 pg/mLN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Ondansetron Level

Frequently asked questions

What triggers this test?
This test is typically ordered if you’re taking ondansetron for nausea/vomiting, especially during chemotherapy or surgery, or if you’re experiencing unusual symptoms that might relate to the medication.
How long does it take to get results?
Results are usually available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will contact you once they’re ready to discuss them.
Can I eat or drink before this test?
You can eat and drink normally before the test, as no fasting is required. However, always follow your doctor’s specific instructions for your blood draw.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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 17, 2026. · Read our editorial policy