Related Experiment Video
Updated: May 2, 2026
Routine Screening Method for Microparticles in Platelet Transfusions
Published on: January 31, 2018
Rapid detection of contaminant bacteria in platelet concentrate using differential impedance
1BioSense Technologies, Inc., Woburn, MA, USA.
Background And Objectives:
Current FDA-approved culture-based methods for the bacterial testing of platelet concentrate (PC) can yield false-negative results attributed to Poisson-limited sampling errors incurred near the time of collection that result in undetectable bacterial concentrations. Testing PC at the point of issue (POI) extends the incubation period for any contaminant bacteria increasing the probability of detection. Data are presented from time-course experiments designed to simulate POI testing of bacterially contaminated PCs at different stages of growth using differential impedance sensing.
Study Design And Methods:
Whole-blood-derived PCs were typically spiked with low numbers of bacteria (approximately 100 CFU/ml) and incubated under standard PC storage conditions. Each infected unit was evaluated every two hours over a 12-h period. All samples were treated with a chemical compound that induces stress in the bacterial cells only. The development of any bacterial stress was monitored by detecting changes in the dielectric properties of the PC using differential impedance.
Results:
Differential impedance measurements and corresponding cell counts at the different time-points are presented for six organisms implicated in post-transfusion-septic reactions. All infected PCs were detected once contaminant bacteria reached concentrations ranging between 0·6 × 10(3) and 6 × 10(3) CFU/ml irrespective of the phase of growth. Results were obtained within 30 min after the start of the assay and without the need for cell lysis or centrifugation.
Conclusion:
Differential impedance sensing can detect bacterial contamination in PC rapidly at concentrations below clinical thresholds known to cause adverse effects.
Insights
Differential impedance sensing rapidly detects bacterial contamination in platelet concentrates (PC) at low concentrations, improving upon traditional culture methods. This method enhances patient safety by identifying contaminants before transfusion.
Area of Science:
- Biomedical Engineering
- Microbiology
- Blood Banking
Background:
- Current bacterial testing of platelet concentrates (PC) faces limitations due to sampling errors, potentially leading to false-negative results.
- Testing PC at the point of issue (POI) offers a longer incubation period, increasing the likelihood of detecting bacterial contaminants.
Purpose of the Study:
- To evaluate the efficacy of differential impedance sensing for rapid bacterial detection in PC.
- To simulate point-of-issue (POI) testing of bacterially contaminated PCs at various growth stages.
Main Methods:
- Platelet concentrates (PCs) were spiked with low bacterial concentrations (approx. 100 CFU/ml) and incubated under standard storage conditions.
- Samples were analyzed every two hours over 12 hours using differential impedance sensing to monitor bacterial stress via dielectric property changes.
- A chemical compound was used to induce bacterial stress without cell lysis or centrifugation.
Main Results:
- Differential impedance sensing successfully detected bacterial contamination in all infected PCs.
- Detection occurred when bacterial concentrations reached 0.6 × 10^3 to 6 × 10^3 CFU/ml, regardless of growth phase.
- Results were available within 30 minutes, demonstrating a rapid and efficient detection process.
Conclusions:
- Differential impedance sensing is a rapid and effective method for detecting bacterial contamination in PC.
- This technique can identify contamination at concentrations below those known to cause adverse effects, enhancing transfusion safety.
