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Bacterial Culture and Susceptibility Testing with Blood Culture Identification and Drug Sensitivity Testing

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

This test checks for the presence of bacteria in your blood and determines which antibiotics could effectively treat any infection found.

Quick summary

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

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

Key facts at a glance

LOINC
103788-6
Short code
Bact Id and susc Bld Pos Doc
Synonyms
Bact Id and susc Bld Pos Doc
Category
coagulation
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Does

A blood sample is taken to detect bacteria that may be causing an infection. If bacteria are found, the test identifies their type and how they respond to different antibiotics. This helps doctors choose the best treatment for your specific infection.

How the Test Works

Your blood is collected in a special tube and sent to a lab. The sample is then split into multiple containers where bacteria, if present, grow over several days. After incubation, the lab tests the bacteria for antibiotic resistance patterns using standardized methods.

When You Might Need This Test

Blood cultures are often ordered if you have symptoms like fever, chills, or unexplained infections, especially if you’ve recently had surgery, received medical devices (like catheters), or have a weakened immune system.

Preparation for the Test

No special preparation is needed. You may experience a brief pinch when the blood is drawn, but it usually doesn’t cause discomfort. If you’re on blood-thinning medications, let your doctor know before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Blood Culture with Antibiotic Susceptibility

Frequently asked questions

This test is critical for diagnosing serious blood infections (sepsis) and guiding appropriate antibiotic therapy. Accurate results ensure you receive targeted treatment, reducing the risk of antibiotic resistance and improving recovery.
Blood cultures can confirm infections that might not show up on other tests, such as fever of unknown origin or recurrent infections. Results help doctors avoid unnecessary antibiotics or switch treatments if needed.
How long does it take to get results from a blood culture?
Results typically take 3 to 7 days, depending on the lab’s process. Some labs may provide preliminary findings sooner, but final antibiotic susceptibility reports may take longer. Follow-up with your doctor for interpretation.
What if my blood culture comes back negative but I still feel sick?
A negative result means no bacteria were detected in your blood sample at the time of testing. However, infections can sometimes be missed or may require different testing (like cultures from other body sites). Discuss persistent symptoms with your doctor to explore further evaluation.
  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