Rapid test to screen blood approved by the FDA

Sep 20 2007

The U.S. Food and Drug Administration (FDA) has given it's approval for the first rapid test to detect bacterial contamination in blood platelets prior to transfusion.

The test, called the Platelet Pan Genera Detection (PGD) Test System is a disposable strip for use in a hospital transfusion service setting and is meant to supplement quality control testing methods currently in use.

The FDA says the test is a significant step in the detection of bacterial contamination of platelets for transfusion; in 30 minutes a sample is prepared, processed and read, providing an additional assurance that the product is free from harmful bacteria.

Blood platelets are used to prevent or treat bleeding in those undergoing chemotherapy for cancer, following a major trauma, during or after surgery, and also for individuals who do not produce their own platelets.

Transfusions with platelets which are contaminated with bacteria places a patient at risk of developing a serious and potentially life-threatening infection of the blood stream known as blood poisoning.

In order to prevent the infection from spreading to the heart and lungs, blood poisoning has to be treated quickly; the bacterial contamination of platelets is the leading infectious cause of transfusion-related patient deaths.

The risk of a patient receiving a transfusion contaminated with bacteria is 1 in 5,000, with hepatitis C virus, one in 1.6 million, or HIV, one in 1.9 million.

To avoid transfusing contaminated platelets, blood centers culture samples of the platelets 24 hours after the donation and the culture is read within the next 24 hours.

Contaminated units are discarded but there is always the possibility that the number of bacteria present at the time of culture may be so low that bacteria are not detected due to sampling limitations.

The rapid testing of blood platelets using the PGD Test System allows for retesting at a time closer to their use and while the system is less sensitive than standard cultures, it is done later when any bacteria possibly present, have multiplied, and are easier to detect.

The FDA has also given approval for a genetic test to help identify patients at risk of excessive bleeding from the commonly used blood thinner Warfarin.

The test detects gene variants linked with an increased sensitivity to the drug.

Warfarin is one of the most widely used drugs and is taken by 2 million patients to prevent blood clots that can cause heart attacks and strokes.

Warfarin however can thin a patient's blood too much which can cause brain hemorrhages or ulcers.

The FDA approval is part of a move toward personalized medicine, in which doctors tailor treatment based on a patient's genetic makeup.