BacTx® Bacterial Detection System
for bacterial contamination of platelets



The BacTx® Assay System has received clearance from the FDA for testing up to 6 units of leukocyte reduced whole blood-derived platelets that are pooled within 4 hours of transfusion. Please contact Immunetics for further details.

Download the package insert »

The BacTx Test provides a rapid and sensitive method for the detection of bacterial contamination in platelets, and is designed to help laboratories meet AABB standard 5.1.5.1.1. This integrated system of reagents, reader, PC and software automatically monitor each sample and report the presence of bacteria in above the detection threshold. The test provides several benefits over culture-based test methods used for this purpose:

    Single assay detection of all bacteria: aerobic, anaerobic, gram-positive and gram negative
    • The BacTx Assay targets peptidoglycan, a universal component of all bacterial cell walls.
    • The BacTx Assay is not species-specific.
    Results in less than 1 hour
    • Only 15 min are needed to prepare 8 samples; tests are run and automatically scored in 30 min
    • Rapid turnaround enables fast results on platelets at any stage of storage
    Small Sample Volume
    • Only 0.5 ml of sample needed.
    • Minimal loss of platelets to testing
    Sensitive
    • Threshold of 103 to 104 cfu/ml for all clinically relevant strains.
    • Meets AABB recommendations for sensitivity in detection of contaminated platelets.
    Specific
    • Clear discrimination between positives and negatives
    • Fewer interferences than in antibody-based assays
    Automated Reader and Report Generation
    • Dedicated photometer monitors reaction and computer interprets results objectively.
    • Eliminates manual reading and interpretation.
  BacTx Reader
   Dedicated PC and Software

Principle of the test
The BacTx test detects peptidoglycan, a cell wall component of both gram-positive and gram-negative bacteria. A peptidoglycan binding protein initiates a series of enzymatic reactions that convert a substrate to a visible color. In the presence of bacteria, color will develop at a rate proportional to the level of bacterial contamination. The BacTx Reader and software automatically monitor the reaction as color intensity changes, providing a kinetic test that rapidly detects bacterial contamination and flags any contaminated platelet units.

Test procedure
A 0.5 mL sample is removed sterilely from a platelet bag and processed through several quick steps, then added to the BacTx reagent tube. Up to 8 samples can be processed in parallel in 15 minutes. The tubes are placed in the BacTx Reader, which continuously monitors color development. Test results are displayed and automatically interpreted by the BacTx software. The assay is complete in 30 minutes or less, depending on the level of contamination. A highly contaminated platelet sample (e.g., 106 CFU/mL or higher) will begin to change color within minutes and will be flagged as a “Fail” by the software as soon as the detection threshold is crossed. If no contamination is detected after 30-minutes of incubation, the platelet bag is flagged as a “Pass”. 

Complete System
The BacTx Rapid Assay System* provides  the reagents, reaction and sample tubes, reader, dedicated PC  and software needed for sample processing, reading and interpretation. You provide only the pipettor, microcentrifuge, vortex mixer and tube rack.

BacTx® Bacterial Detection Kit Reagent Pack
Contains reagents and reaction tubes sufficient for 32 tests
Catalog # DK-B502-032
Kit components:

  • BacTx Reaction Tubes. 32 sealed glass tubes each containing lyophilized detection reagent for 1 test
  • Lysis Reagent, 1 x 60 mL
  • Extraction Reagent, 1 x 60 mL
  • Neutralization Reagent, 1 x 60 mL
  • Positive Control. Purified peptidoglycan from Bacillus subtilis, 1 x 1.8 mL
  • Negative Control, 1 x 1.8 mL
  • Sterile 2 mL Microfuge tubes, qty 50
  • Sterile 1.5 mL Microfuge tubes, qty 50

*The BacTx® Kit, reagents and associated protocols are covered under US Patent 7,598,054, and other foreign and pending patents.

BacTx Reader
8 sample capacity
Part # BTX-001

Laptop PC with BacTx Assay Software
Part # AA-C018-000

BacTx Publications

  • Jacobs, MR et al. Detection of Bacteria in Leukocyte-Reduced Whole Blood Derived Platelet Units using the Immunetics BacTx® Test. 2010, Presentation at AABB Meetings. Download pdf
  • Krueger NX et al. Slow Growing Bacterial Strains in Platelet Units Evade Detection with Culture Systems But Are Detected by the BacTx™ Assay, a Rapid Test for Bacterial Contamination of Platelet Units. 2009, Presentation at AABB Meetings. Download pdf
  • BacTx™ Assay for Bacterial Contamination of Platelets Detects Bacteria Missed by Automated Culture Systems. 2008, Presentation at AABB Meetings. Download pdf