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Microbiological culture and sensitivity for *specific* bacteria (e.g., *Staphylococcus*, *Pseudomonas*, *Escherichia coli*) from a blood specimen

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

This test helps identify bacteria in your blood and determine which antibiotics could effectively treat an infection.

Quick summary

["Blood cultures help diagnose infections and guide antibiotic treatment."]

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

Key facts at a glance

LOINC
12452-9
Short code
Epi Cells Smn Ql Micro
Synonyms
Epi Cells Smn Ql Micro
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
microscopy-light
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 This Test Measures

The test involves collecting a blood sample to grow bacteria in a controlled environment. If bacteria are present, they will multiply over time, allowing lab technicians to identify the type of bacteria and check how well different antibiotics work against it.

Why It’s Done

Blood cultures are typically ordered if you have symptoms of a serious infection, such as fever, chills, or signs of sepsis (a life-threatening response to infection). They may also be used before starting antibiotic treatment to confirm or rule out an infection.

How the Test Works

Blood is drawn into special tubes that contain a blood culture medium. This medium supports the growth of any bacteria present. The sample is then incubated for several days. If bacteria grow, they are isolated, identified, and tested for antibiotic resistance.

Preparation for the Test

No special preparation is needed for this test. However, inform your healthcare provider about any medications you’re taking, especially antibiotics, as they may affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Blood Culture with Antibiotic Susceptibility Testing

Frequently asked questions

How long does it take to get results?
Results can take 2–7 days or longer, depending on bacterial growth and testing methods. Delayed results may require additional follow-up or alternative testing.
What does a positive result mean?
A positive result means bacteria were found in your blood. Your doctor will work with lab findings to choose the best antibiotic treatment for your specific infection.
Can I have antibiotics before getting blood cultures?
Yes, but it may affect test results. If you take antibiotics before testing, your doctor may need to adjust the interpretation or request additional tests.
  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