Bacterial contamination of platelets is considered the greatest infectious risk of blood product transfusion today at about 1 in 2000 platelet units, which is several orders of magnitude greater than that of HIV. Bacterial contamination at high levels can lead to severe morbidity or mortality in transfusion recipients. The American Association of Blood Banks issued directives in 2004 and 2011 requiring bacterial testing on all platelet units. Two recent studies have demonstrated that current FDA-approved culture-based methods that test for contamination 1 to 4 days prior to transfusion miss a majority of contaminated units. The time elapsed between sampling and actual transfusion and the associated risk of bacterial contamination is a fundamental problem that cannot be addressed by current culture-based platelet testing. A rapid and sensitive point-of-issue test for bacterial contamination would overcome this problem by providing an assessment of potential contamination immediately prior to transfusion. Such a test would be used by a hospital laboratory close to the point of transfusion or by a transfusion center preparing to ship platelet units to a clinical center. A rapid test would ideally require less than 15 min, have detection sensitivity of 104 CFU/mL or better, be fully automated, and be comparable in cost to current tests. BacTx technology, developed by Immunetics for detection of bacterial contamination in platelets, employs a unique and innovative assay chemistry capable of rapidly detecting both Gram-positive and Gram-negative bacteria in platelet units. The first-generation BacTx Bacterial Detection Kit recently received clearance from FDA (CBER) as a quality control test for pooled, leukocyte-reduced whole blood derived platelets, but this test is not ideally suited for use as a point of issue test due to its length (45 min) and complexity (requiring centrifugation and accurate pipetting). In the Phase I project, we successfully demonstrated feasibility of a simple, filter-based BacTx assay which is rapid (<15 min) and highly amenable to automation, while maintaining the high sensitivity and specificity of the original BacTx test. In Phase II, we will optimize and configure the rapid test for automated performance and will design, build and evaluate prototype instruments and software to run the test. The instrument and software development will be carried out in collaboration with engineering partners who have many years of experience in the development of medical test systems with comparable functionality. At the conclusion of Phase II, we will have developed and validated an integrated rapid BacTx test system ready for clinical studies aimed at 510(k) approval. Commercialization of this rapid test will enable a paradigm shift in platelet testing and a significant reduction in the number of bacterially contaminated platelet units transfused into critically ill patients. Furthermore, adopton of the rapid BacTx test could ultimately lead to a change in policy regarding platelets, significantly reducing costs for blood banks by allowing an extension of the storage life of platelet units from 5 to 7 days.

Public Health Relevance

Bacterial contamination of platelets is considered the greatest infectious risk of blood product transfusion today at about 1 in 2000 platelet units, which is several orders of magnitude greater than that of HIV. We have developed a rapid (<15 min), point-of-transfusion screening test for detection of bacterial contamination in platelet units that meets or exceeds FDA guidelines. We propose to adapt this test to be run by a simple automated device suitable for operation by non-specialized personnel in a transfusion center or hospital laboratory. Implementation of this rapid test will prevent severe or fatal septic transfusion reactions and lead to better health outcomes for critically ill patients receiving platelet transfusions.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Small Business Innovation Research Grants (SBIR) - Phase II (R44)
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Special Emphasis Panel (ZRG1-IDM-V (12))
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Mitchell, Phyllis
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Immunetics, Inc.
United States
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