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Plasma/Serum *Escherichia coli* (bacteria) quantitative culture

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

This test checks for the presence of *Escherichia coli* bacteria in your blood or serum, helping identify infections caused by this common gut bacterium.

Quick summary

["Assesses bacterial infection risk in blood or serum samples."]

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

Key facts at a glance

LOINC
100908-3
Short code
P aerugns Lower resp Ql Cult
Synonyms
P aerugns Lower resp Ql Cult
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
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

What Is This Test Measuring?

This test detects and quantifies *E. coli* bacteria in your plasma or serum. It’s used to diagnose infections where this bacterium may be involved, such as bloodstream infections (sepsis) or other serious illnesses.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fever, chills, or signs of infection, or if you’re at higher risk for bacterial infections (e.g., weakened immune system, recent surgery). It can also guide treatment decisions for suspected bacterial infections.

How Is the Sample Collected?

A blood sample is drawn from a vein, typically in your arm. The blood is then processed to separate plasma or serum for testing. This is a standard procedure and may cause a slight pinch or discomfort.

What Does a Positive Result Mean?

A positive result indicates the presence of *E. coli* bacteria in your sample. This could suggest an infection, though other bacteria or conditions may also be present. Your doctor will interpret results alongside your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

E. coli Culture

Frequently asked questions

How long does it take to get results?
Results from a bacterial culture typically take 2–5 business days, depending on the lab’s processing speed and whether additional tests (like antibiotic sensitivity) are needed. Your doctor will contact you once results are available.
What if I have a mild infection or no symptoms?
Even if you don’t feel sick, a positive culture may be needed to confirm a diagnosis (e.g., after surgery or for monitoring chronic conditions). If you’re asymptomatic, your doctor may discuss whether follow-up testing is necessary.
Can I prevent false positives or negatives?
To avoid false positives, avoid recent antibiotic use (ask your doctor about timing) and inform staff if you’ve had recent infections. False negatives are rare but may occur if the sample isn’t collected properly. Follow your doctor’s instructions for sample handling.
  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