Serum/plasma *Substance concentration* by immunoassay (tetramethylbenzidine signal) for *Escherichia coli* antigen detection
This test measures the presence of *Escherichia coli* bacteria in your blood or plasma using an immunoassay method. It helps identify infections caused by this common gut bacterium that may have spread beyond the intestines.
["Detects bloodstream infections by *E. coli* with a simple blood draw."]
Key facts at a glance
- LOINC
- 105770-2
- Short code
- P aerugns DNA Ct Bld Pos Qn NAA+probe
- Synonyms
- P aerugns DNA Ct Bld Pos Qn NAA+probe
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- probe-amp-tar
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test detects *Escherichia coli* antigens in your blood or plasma. Antigens are specific molecular markers that the immune system recognizes as foreign. This test specifically looks for proteins produced by *E. coli* bacteria, which can indicate an active infection.
Why It’s Done
Your healthcare provider may order this test if you have symptoms like fever, chills, or signs of infection such as rapid heartbeat or confusion, especially if you’ve recently had a urinary tract infection, surgery, or a condition that weakens your immune system.
When Results Might Be Abnormal
If the test is positive, it suggests the presence of *E. coli* in your blood, which could indicate a serious infection requiring immediate medical attention. Negative results mean no detectable *E. coli* antigens were found in this sample.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into a vein (usually in your arm) to draw a blood sample. The process is quick and usually painless.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is primarily used to diagnose bloodstream infections caused by *E. coli*. It can help confirm if the bacteria have spread beyond the gastrointestinal tract, guiding treatment decisions such as starting antibiotics.
Short name
E. coli Antigen (Serum/Plasma) IA-TMB
Frequently asked questions
What does a positive result mean?
Can this test detect all types of *E. coli* infections?
How soon will I get my results?
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