Skip to content

Fluoroquinolone (e.g., ciprofloxacin, levofloxacin) Substance Concentration in Serum

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

This test measures the amount of fluoroquinolone antibiotics (like ciprofloxacin or levofloxacin) in your blood. It helps doctors check if your medication levels are within safe ranges.

Quick summary

["This test ensures your antibiotic is working effectively and avoids potential side effects from too much or too little in your system."]

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

Key facts at a glance

LOINC
50697-2
Short code
FLUAV Ag Islt
Synonyms
FLUAV Ag Islt
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

Doctors may order this test if you’re taking fluoroquinolone antibiotics for infections such as urinary tract infections, gastrointestinal issues, or certain types of pneumonia. It helps monitor your treatment and adjust doses if needed.

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 a blood sample. It usually takes a few minutes, and you may feel a brief pinch.

What the Test Results Mean

Results show how much fluoroquinolone is in your blood at the time of testing. Low levels may mean the drug isn’t working well, while very high levels could indicate side effects or improper dosing.

Common Uses and Considerations

This test is most useful for patients on long-term fluoroquinolone therapy or those with kidney issues, as it helps prevent overuse or toxicity. Always follow your doctor’s instructions for timing and dosage.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Fluoroquinolone Level (Serum)

Frequently asked questions

When might I need this test?
You may need this test if your doctor prescribes fluoroquinolone antibiotics for a prolonged course or if you have conditions like kidney disease that affect how the drug is processed in your body.
How long will I need to wait for results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will discuss them with you during your follow-up visit.
Can I eat or drink before this test?
Yes, you can eat and drink normally before the test. No fasting is required, unlike some other blood tests.
  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