Skip to content

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

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

This test measures the amount of a specific fluoroquinolone antibiotic in your blood serum to ensure proper dosing and assess whether the drug is working effectively against an infection.

Quick summary

["Knowing your antibiotic level helps doctors adjust your treatment for better infection control and fewer side effects."]

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

Key facts at a glance

LOINC
86565-9
Short code
FLUAV Ag Tiss Ql IF
Synonyms
FLUAV Ag Tiss Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 fluoroquinolone antibiotics to treat or prevent infections like urinary tract infections, respiratory infections, or certain types of bacterial infections. It helps ensure the antibiotic is at an effective concentration in your blood.

How the Test Works

A blood sample is taken from a vein, usually in your arm. The sample is then analyzed using a sensitive laboratory method to measure the antibiotic’s presence in your serum.

What to Expect Before the Test

No special preparation is needed, but inform your doctor about any other medications you’re taking, as they may affect test results or your antibiotic dose.

What to Expect During the Test

You’ll lie down comfortably while a healthcare provider inserts a small needle into your vein. The blood sample is drawn quickly, and you may feel a slight pinch or discomfort.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Antibiotic Level (Serum)

Frequently asked questions

Low levels of the antibiotic may mean it’s not working well against the infection, while very high levels could indicate side effects or improper dosing. This test helps balance effectiveness and safety.
This test is primarily used to confirm whether your antibiotic dose is appropriate for your condition and to monitor for potential side effects.
What does a high or low result mean?
A high result might suggest you’re taking too much of the drug, which could cause side effects like nausea, tendon pain, or allergic reactions. A low result could mean the infection isn’t being fully treated, so your doctor may adjust your dose or try a different antibiotic.
How often should I get this test?
Your doctor will determine how often you need this test based on your treatment plan, infection type, and response to the medication. Typically, it’s done during or shortly after starting treatment, then periodically as needed.
  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