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Levofloxacin Concentration in Serum or Plasma (Pharmacokinetic Monitoring)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of the antibiotic levofloxacin in your blood, helping your healthcare provider determine if it’s working effectively and whether you need to adjust your dose.

Quick summary

["Your levofloxacin levels help ensure you’re getting the right amount of medication to fight infection safely."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
20396-8
Short code
levoFLOXacin Islt MIC
Synonyms
levoFLOXacin Islt MIC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mic
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 levofloxacin to treat or prevent bacterial infections. It helps assess whether the drug is reaching the right concentration in your bloodstream to be effective while minimizing side effects.

What to Expect Before the Test

No special preparation is needed. The test involves a simple blood draw from a vein, usually in your arm. You may feel a slight pinch, but it’s quick and painless.

What the Results Mean

Results help determine if your levofloxacin dose is appropriate. Low levels may mean the drug isn’t working well, while very high levels could indicate potential side effects. Your doctor will interpret these results in the context of your overall health and treatment plan.

Common Reasons for Testing

This test is often used in patients with infections like urinary tract infections, respiratory infections, or skin infections. It’s also used in monitoring patients who require long-term antibiotic therapy to avoid resistance or toxicity.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Levofloxacin Levels

Frequently asked questions

Will I need to fast before this test?
No fasting is required for this blood test. However, inform your doctor about any medications you’re taking, including over-the-counter drugs or supplements, as they may affect results.
How long will it take to get my results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing schedule. Your doctor will discuss the findings with you during your follow-up visit.
Can I drink water before the blood draw?
Yes, you can drink water before the blood draw unless your doctor specifies otherwise. Avoid caffeine or alcohol before testing, as they might influence test results.
  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 16, 2026. · Read our editorial policy