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Levofloxacin Concentration in Plasma (Quantitative)

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

This test measures the amount of the antibiotic levofloxacin in your blood plasma. It helps doctors assess whether your dose is effective and monitor for potential side effects.

Quick summary

["This test helps ensure your antibiotic is working properly and stays at safe levels in your blood."]

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

Key facts at a glance

LOINC
73306-3
Short code
levoFLOXacin ind plt IgM SerPl Ql FC
Synonyms
levoFLOXacin 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 This Test Is Done

Your healthcare provider may order this test if you’re taking levofloxacin (a fluoroquinolone antibiotic) for an infection. It helps determine if your dose is appropriate for your condition and whether the drug is still active in your system.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood, similar to other blood tests. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results show the concentration of levofloxacin in your plasma. Higher levels may indicate the drug is working well, while very low levels could mean the infection isn’t fully treated or the dose needs adjustment. Your provider will interpret these results in the context of your medical history and symptoms.

Common Reasons for Testing

This test is often used in cases of complex infections, infections requiring long-term treatment, or when the infection doesn’t respond to standard doses. It’s also used in monitoring patients with kidney issues, as kidney function affects how quickly the drug leaves your body.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Plasma Levofloxacin Level

Frequently asked questions

What could cause abnormal results?
Abnormally high levels might suggest your body isn’t processing the drug well (e.g., kidney problems) or that you’re taking too much. Very low levels could mean the infection isn’t fully treated or the drug isn’t reaching the infection site effectively. Always discuss results with your provider.
How long will I need to wait for results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your provider will contact you with the findings.
Can I drink water before this test?
Yes, you can drink water unless your provider specifies otherwise. Avoid caffeine or alcohol before the test, as they may affect blood composition.
  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