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Blood Culture with Quantitative Measurement of Bacterial Growth (Qualitative and Quantitative Analysis)

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

This test checks for bacteria or fungi in your blood, which may indicate an infection. It involves drawing blood and growing it in a lab to identify any pathogens.

Quick summary

Blood cultures help diagnose serious infections that require prompt treatment.

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

Key facts at a glance

LOINC
71472-5
Short code
DATEOFBLOODCULTURE
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
87040
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

Why Is This Test Done?

Your doctor may order a blood culture if you have symptoms like fever, chills, or unexplained infections. It’s also used to confirm infections in people with weakened immune systems or those receiving chemotherapy. Blood cultures are especially important if you’ve had recent surgery, a central line, or other procedures that could introduce bacteria into your bloodstream.

What Does the Test Involve?

A small amount of blood is drawn from a vein, usually in your arm. The blood is placed in special containers that allow bacteria to grow if present. The lab will monitor these containers for signs of microbial growth over time.

How Are Results Interpreted?

Results are reported as either positive (indicating likely bacterial or fungal growth) or negative (no detectable pathogens). If positive, further testing may be done to identify the specific type of infection.

What Are Common Causes of Positive Results?

Positive blood cultures can occur due to true infections (like sepsis), contamination from the blood-drawing process, or other medical devices (e.g., catheters) that may introduce bacteria.

Frequently asked questions

How long does it take to get blood culture results?
Results can take anywhere from a few days to a couple of weeks, depending on whether the lab detects growth and identifies the specific bacteria or fungus.
What if my blood culture comes back positive but I don’t feel sick?
A positive result doesn’t always mean you’re sick. Sometimes, bacteria can be found in the blood due to contamination from the blood draw or from medical devices. Your doctor will discuss the results and next steps with you.
Can I take antibiotics before my blood culture?
No, taking antibiotics before the test can interfere with the results. If you suspect an infection, tell your doctor immediately so they can adjust your care plan.
  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