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Levofloxacin Concentration in Serum

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

This test measures the amount of the antibiotic levofloxacin in your blood serum. It helps determine if the drug is working effectively in your system.

Quick summary

["This test helps doctors check if your levofloxacin levels are within the right range for your treatment."]

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

Key facts at a glance

LOINC
21367-8
Short code
levoFLOXacin Islt KB
Synonyms
levoFLOXacin Islt KB
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
agar-diffusion
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 levofloxacin to treat or prevent bacterial infections. It helps ensure the drug is at an appropriate level to fight infection without causing unnecessary side effects.

What Does This Test Measure?

Levofloxacin is an antibiotic used to treat infections caused by bacteria. This test quantifies the concentration of levofloxacin in your blood serum, measured in micrograms per milliliter (mcg/mL).

How Is the Sample Collected?

A blood sample is drawn from a vein, usually in your arm, by a healthcare professional. The serum portion of the blood is then analyzed in a lab.

What Are Possible Results?

Results are typically reported as a numerical value indicating the levofloxacin concentration in your blood. Your doctor will interpret these results in relation to your treatment plan.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: This test is critical for monitoring antibiotic levels to prevent underdosing (infection may not be fully treated) or overdosing (increased risk of side effects). Proper dosing ensures effective infection control while minimizing harm.

Short name

Levofloxacin Level

Frequently asked questions

What does a levofloxacin level test tell me about my treatment?
It tells your doctor whether your antibiotic dose is working as intended. High levels may indicate the drug is too strong, while low levels could mean the infection isn’t being fully treated.
How long will it take to get my results?
Results are usually available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you once they’re ready.
Can I eat or drink before this test?
You may eat and drink normally unless instructed otherwise by your doctor. Typically, fasting isn’t required for this test.
  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