Babesiosis Screening Tests For Blood Donors Just Got Approval From The FDA

According to a story from, the FDA recently approved donor screening tests for blood donors that will test potential donors for the parasite Babesia microti, a type of protist that can be transferred to humans from tick bites. The primary tick species responsible is Ixodes scapularis, commonly known as the black-legged tick or the deer tick. The organism can cause a disease called babesiosis, which is similar to malaria in some respects.

The necessity for screening in blood donors is primarily due to that fact that many people that have B. microti in their bloodstream do not experience any symptoms of disease, meaning that it can go completely unnoticed by the individual. About half of children and a quarter of adults with the parasite have no symptoms. When symptoms do appear, they normally consist of fever and hemolytic anemia, which is similar to malaria symptoms. People can develop symptoms one to four weeks after being bitten by an infected tick, although people who are infected from a blood transfusion may develop symptoms substantially later, up to nine weeks. Other symptoms include random sweating, chills, and low platelet count. More advanced disease can cause nausea, pink eye, depression, weight loss, anorexia, and jaundice. Symptoms can last up to several months, and babesiosis can only be accurately diagnosed in a limited number of specialized labs. To learn more about this disease, click here.

The screenings will test for both the presence of microbe antibodies and for the presence of DNA in given blood samples. It should be noted that the donor screening tests are not intended for the diagnosis of babesiosis in affected individuals. Some investigational implementation of donor tests for B. microti has been ongoing since 2012, and has resulted in many infected samples being removed from the bloody supply. Data from use over the years demonstrated that the donor screenings were effective in detecting the parasite.

As of now, the FDA has not released any specific instructions for the use of screening tests to detect the parasite in blood samples, but it is anticipated that the FDA will eventually develop a list of guidance measures that will help prevent babesiosis transmissions from blood transfusions.

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