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Antibiotic Concentration (Cefuroxime) in Plasma

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

This test measures the amount of the antibiotic cefuroxime in your blood plasma. It helps doctors determine whether your dose is effective and monitor your response to treatment.

Quick summary

["This test helps ensure your antibiotic is working properly and adjusts your treatment if needed."]

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

Key facts at a glance

LOINC
147-9
Short code
CEFSBT
Synonyms
Cefuroxime Parenter Titr SBT
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or red-top tube (no anticoagulant); sterile cryovials recommended for frozen transport
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Serum bactericidal titer (Schlichter test) - microdilution or macrodilution broth methodology using serial two-fold dilutions of patient serum incubated with a standardized bacterial inoculum
CPT
87197
SNOMED
104281000
Specimen volume
2-5 mL of serum (minimum 1 mL)
Stability
Serum should be frozen at -70°C or colder for prolonged storage; refrigerated (2-8°C) stability is limited to 24-48 hours; ideally processed immediately or stored frozen until testing
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you’re receiving cefuroxime therapy, particularly for infections that require higher doses or prolonged treatment. It helps optimize your medication to avoid resistance or side effects while targeting the infection.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your vein (venipuncture) or a blood sample drawn from your arm. If you’re on intravenous cefuroxime, your plasma level may be checked during or shortly after infusion.

What the Test Results Mean

Results are typically reported as a concentration value (e.g., micrograms per milliliter). Your doctor will compare this to your treatment plan to guide dosing adjustments.

Possible Side Effects or Considerations

Cefuroxime is generally well-tolerated, but high plasma levels may cause mild side effects like nausea or allergic reactions. If you experience severe reactions (e.g., rash, difficulty breathing), seek medical attention immediately.

Reference range

Titer >=1:8 generally considered indicative of adequate antibacterial activity for most serious infections; Titer >=1:16 recommended for endocarditis and other deep-seated/life-threatening infections; specific interpretive criteria depend on infection site, pathogen, and host factorsN/A

Specimen: serum

No special patient preparation required. Specimen should be collected at steady-state pharmacokinetic conditions (typically after at least 3-5 doses). Trough and peak levels (collected 30 minutes before next dose and 30-60 minutes after dose completion, respectively) are commonly obtained to guide dosing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Cefuroxime Plasma Level

Frequently asked questions

How does cefuroxime concentration relate to infection control?
Plasma levels of cefuroxime help ensure the antibiotic reaches therapeutic levels in your bloodstream to effectively fight bacteria. Low levels may indicate insufficient dosing, while excessively high levels could increase side effects. Your doctor may adjust your dose based on these results to balance effectiveness and safety.
Can this test detect resistance to cefuroxime?
This test alone does not directly measure bacterial resistance. However, monitoring plasma levels helps optimize treatment to reduce the risk of resistance developing over time, as improper dosing can select for resistant bacteria.
What if my test results are outside the expected range?
If your results are unusually high or low, your doctor will review your treatment plan. They may recommend changes in dosing frequency, duration, or switch to a different antibiotic if needed. Follow-up tests may also be ordered to assess your infection’s response.
  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