Beta-Lactamase (ESBL) Detection in Serum/Plasma by Immunoassay
This test checks for the presence of extended-spectrum beta-lactamase (ESBL) enzymes in your blood, which can make certain antibiotics less effective against certain bacteria.
["ESBL can help doctors determine if your infection may require different antibiotic treatment."]
Key facts at a glance
- LOINC
- 73046-5
- Short code
- CEFNEUTAB
- Synonyms
- Cefepime (neut) IgG SerPl Ql FC
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube (no anticoagulant) or serum separator tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- flow-cytometry
- CPT
- 86022
- Specimen volume
- 2-5 mL of whole blood yielding at least 1-2 mL of serum
- Stability
- Serum stable at room temperature for 4 hours; refrigerated (2-8°C) for 24-48 hours; frozen at -20°C or below for longer storage. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test if you have a bacterial infection that doesn’t respond well to standard penicillin or cephalosporin antibiotics. ESBL-producing bacteria can spread in healthcare settings and communities, so early detection helps guide treatment choices to prevent resistance.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm to draw a blood sample. The blood is processed to separate serum or plasma for testing.
What the Test Results Mean
Positive results indicate the presence of ESBL enzymes, which may mean your infection could be caused by bacteria resistant to certain antibiotics. Negative results suggest standard antibiotics might still work effectively.
Common Causes of Positive Results
ESBL is often found in infections caused by bacteria like *Escherichia coli* or *Klebsiella* that have developed resistance through exposure to antibiotics.
Reference range
Negative (antibody not detected)N/A
No fasting required. Patient should be informed that this test detects drug-induced neutrophil antibodies and is used in the evaluation of suspected drug-induced neutropenia or agranulocytosis associated with cefepime therapy.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
ESBL Screen (Serum/Plasma)
Frequently asked questions
What does a positive result mean for my treatment?
How long does it take to get my test results?
Can I take antibiotics before getting this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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