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Levofloxacin Concentration in Serum (Quantitative)

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

This test measures the amount of the antibiotic levofloxacin in your blood serum. It helps determine whether your current dose is effective and if you need adjustments.

Quick summary

["This test checks your antibiotic levels to ensure proper dosing and avoid side effects."]

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

Key facts at a glance

LOINC
76042-1
Short code
levoFLOXacin Islt Slgr Mcbct AB 4.0
Synonyms
levoFLOXacin Islt Slgr Mcbct AB 4.0
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
method-for-slow-growing-mycobacteria-antibiotic-concentration-at-ug-ml
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 for an infection and want to confirm the drug is working at the right level in your blood. It’s also used in monitoring patients with kidney issues or those who may be at higher risk of antibiotic resistance.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. The process takes a few minutes, and you may feel a brief pinch. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results help your doctor adjust your levofloxacin dose if needed. Low levels may mean the drug isn’t working well, while very high levels could indicate side effects or improper dosing. Your provider will interpret the results in the context of your overall health.

Common Reasons for Testing

This test is often used in hospital settings to guide antibiotic therapy, especially for infections like pneumonia, urinary tract infections, or skin/soft tissue infections. It’s also used in research or specialized clinical trials.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Levofloxacin Level

Frequently asked questions

What are the typical reference ranges for this test?
Reference ranges can vary by lab and patient factors like kidney function. Your doctor will provide your specific results and explain what they mean for your treatment. Always follow their guidance.
How long does it take to get my results?
Results are usually available within 1–3 business days, depending on your lab. Your provider will contact you directly with the results once they’re ready.
Can I eat or drink before this test?
You can eat and drink normally before the test unless your provider gives specific instructions. No fasting is required.
  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