Blood Culture : There is more to it than a simple blood test

Blood culture is indicated when blood stream infections are suspected.

Bacteremia: presence of bacteria in blood – it can be transient, continuous or intermittent.

Fungemia: presence of fungus in blood

Septicemia: bacteria infection in any part of the body enters through the bloodstream. Microbial invasion of the bloodstream resulting from any organism can have serious immediate consequences, including shock, multiple organ failure, disseminated intra-vascular coagulation and death.

Blood Stream Infections (BSI)

BSI is associated with major morbidity and mortality worldwide. Mortality rates can range from 20% to 50%.


  • Primary (no focus) or secondary when associated with clinical or microbiological confirmation of infection at a defined body site.
  • Hospital-acquired or community-acquired.
  • A widely accepted third category is that of healthcare-associated BSI be recognized among patients who have community-onset BSI and significant recent healthcare system exposure.

When should You do a Blood Culture Test?

Skin Rash

Suspect systemic bacterial or fungal infection

High Fever

Recurring moderate to high fever



Other accompanying symptoms

Rapid breathing





Increased heart rate

How can you prevent Serious Systemic Infections?

Controlled blood sugars

Taking appropriate treatment without delay in case of local infections

Hygienic care of wounds

Avoid places where bacteria / fungus may be prevalent

Why should you do a Blood Culture Test?

Confirm bacterial and fungal infections/sepsis in blood

Avoid taking antibiotics unnecessarily

Identify causative infectious agent

 Avoid spreading of infection by correct diagnosis early on

Detect life-threatening conditions such as infective endocarditis

Who is prone to blood infections?


HIV+ or AIDS Patients

Cancer Patients

New born and Children with Low Immunity

Recent Infection, still Recovering

Recent Surgery

Auto-immune suppressant Medication / Intravenous drug users

Elderly People

Blood Culture Methods

Manual blood culture

Advantage : lower price/ bottle

Limitations :

  • Insensitive compared to newer and automated systems (non standardized media)
  • Labor intensive – chance of contamination
  • Longer time to detection
  • Longer patient stay

Automated system used by ASPIRA

Advantages of BD BactecTM Fx blood culture

  • Fluorescence technology detection: Microorganisms if present, metabolize nutrients in the Bactec culture vial and release CO2 and utilize O2 in the medium. This increases the fluorescence of the vial sensors which is continuously monitored by the instrument and the vial flags positive indicating presumptive presence of viable organisms. Thus rapid detection of growth is enabled.
  • More Sensitive, Accurate and Efficient
  • Lesser Chances of Contamination
  • Superior Resin-based media which inactivate antimicrobials that may interfere with microorganism growth and mechanically break up WBCs and RBCs so intracellular organisms are released and enhance sensitivity.
  • Different culture bottles with media specifically optimized for different requirements like aerobic culture, anaerobic culture, pediatric sample, fungi and mycobacteria, etc are available.
  • Agitation provides additional enhancement of organism growth and detection.

Number of Blood Cultures

As periodicity of microorganisms in the bloodstream may be characteristic for some diseases, patterns of bacteremia must be considered in establishing standards for the timing and number of blood cultures.

  • If the volume of blood is adequate, usually two or three blood cultures are sufficient to achieve the optimum blood culture sensitivity.
  • For patients who have received prior antibiotic therapy, three separate blood collections of 16 to 20 ml each, and an additional blood culture or two taken on the second day, if necessary, detects most etiologic agents of endocarditis.

Types of Culture Bottles

Several media are available for use with the BD BACTEC FX40 system. These include:

BD BACTEC Standard/10 Aerobic /F
Indicated for 3.0 to 10.0 mL (8.0 to 10.0 mL optimal) blood volume.
BD BACTEC Plus Aerobic /F
Contains resins for antibiotic neutralization. Indicated for 3.0 to 10.0 mL (8.0 to 10.0 mL optimal) blood volume.
BD BACTEC Standard Anaerobic /F
Indicated for 3.0 to 7.0 mL (5.0 to 7.0 mL optimal) blood volume.
BD BACTEC Peds Plus /F
Optimized for use with pediatric patients and for low blood volume specimens (1.0 – 3.0 mL optimal; 0.5 to 5.0 mL indicated). Contains resins for antibiotic neutralization.
BD BACTEC Plus Anaerobic /F
Contains resins for antibiotic neutralization. Indicated for 3.0 to 10.0 mL (8.0 to 10.0 mL optimal) blood volume.
BD BACTEC Lytic/10 Anaerobic /F
Non-resin medium containing the blood lysing agent saponin. The lysis of red cells provides nutrients for microbial growth and reduced blood background. The lysis of white cells releases phagocytized organisms. Indicated for 3.0 to 10.0 mL (8.0 to 10.0 mL optimal) blood volume.
BD BACTEC Myco/F Lytic
Specialized medium for the detection of yeast, fungi, and mycobacteria from blood. When yeast or fungi are suspected, the medium may be used to culture sterile body fluids. Indicated for 1.0 to 5.0 mL (3.0 to 5.0 mL optimal) blood volume. A supplement may be required for use with non-blood specimens.
Selective culture medium specifically designed for the recovery of fungi from blood culture specimens. Accepted specimen volume range is 3.0 to 10.0 mL.

About Aspira

Aspira is India’s first fully automated pathlab and diagnostic centre, that lets patients and customers interact with the process at every stage through its advanced IT System and Analytics. You can trust Aspira to provide accurate reports with faster turnaround time, that can help quick-start the doctor’s treatment.

We at Aspira, process each sample with utmost care. We offer full diagnostic services in the area of Andrology. Stringent quality control measures and CASA software working on barcoded samples ensures reliable results with complete traceability. Aspira’s integrated digital system enables you to track your sample and retrive reports from any connected device.