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Serum or plasma concentration of cefuroxime (antibiotic)

Published: August 9, 2026Updated: August 11, 2026

This test measures the amount of the antibiotic cefuroxime in your blood, either in serum or plasma. It helps doctors assess how your body is responding to treatment for infections caused by bacteria sensitive to this medication.

Quick summary

["This test helps track antibiotic effectiveness and adjust treatment if needed."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 11, 2026Editorial policy

Key facts at a glance

LOINC
80617-4
Short code
CEFUF
Synonyms
Cefuroxime.free SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top serum clot tube or serum separator tube (SST); avoid gel separator tubes if possible for free drug analysis due to potential absorption concerns
Units
N/A
Ref low
2
Ref high
20
Critical range
1 N/A – 100 N/A
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) or High-Performance Liquid Chromatography (HPLC) with ultrafiltration for free drug fraction separation
CPT
80299
SNOMED
443450006
Specimen volume
2.0 mL serum (minimum 1.0 mL); requires ultrafiltration step, so adequate volume is critical
Stability
Serum stable for 24 hours at room temperature (20-25°C), 7 days at 2-8°C, and 30 days at -20°C or below. Freeze and avoid repeated freeze-thaw cycles. Process and separate serum promptly (within 2 hours of collection).
Hemolysis max
100
Lipemia max
200
Icterus max
150
TAT
24–72 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you’re taking cefuroxime to treat a bacterial infection. Monitoring your levels helps ensure the medication is working properly and avoids potential side effects from too much or too little in your system.

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 is quick and usually painless. If you’re on blood thinners or have a history of bleeding issues, let your doctor know beforehand.

What the Test Results Mean

Results show how much cefuroxime is in your blood at the time of testing. They don’t provide a direct range, but they help guide whether your dose should be adjusted. Your doctor will interpret these results in the context of your overall health and treatment plan.

Possible Causes of Abnormal Results

Low levels might indicate the infection isn’t fully responding to the antibiotic, while very high levels could suggest kidney problems or improper dosing. Your doctor will discuss these findings with you and adjust your treatment plan if necessary.

Reference range

Therapeutic range for free cefuroxime: 2.0-20.0 mg/L (depends on infection site and MIC of causative organism); trough levels typically maintained above 2.0 mg/L for susceptible organismsN/A

Specimen: serum

No special patient preparation required. Specimen should be drawn at specified time relative to dose (typically trough level just before next dose, or peak 30-60 minutes after IV infusion completion). Patient should be on a stable dosing regimen for at least 24-48 hours prior to sampling for accurate steady-state measurement.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cefuroxime Levels

Frequently asked questions

How often should I expect this test?
This test is typically done during your treatment period, often at specific intervals (e.g., 24–48 hours after dosing) to monitor cefuroxime levels. Your doctor will determine the timing based on your infection and response to treatment.
What if my results are outside the expected range?
If your results are unusual, your doctor may adjust your medication dose, switch to a different antibiotic, or investigate other health factors affecting your response. They’ll explain the next steps based on your specific situation.
Can I eat or drink before this test?
You can eat and drink normally before the test unless your doctor instructs otherwise. Blood tests don’t require fasting unless measuring substances like glucose or lipids, which would require special instructions.
  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 11, 2026. · Read our editorial policy