Plasma Screening Improves
Food and Drug Administration Approves New Test to Screen Plasma for HIV and Hepatitis C
December 2001/January 2002
Studies conducted by Alpha Therapeutic Corporation and National Genetics Institute, Inc. (NGI) concluded that a new test to screen plasma donations for HIV and hepatitis C can identify HIV-1 up to four days earlier than the currently available serologic tests. In addition, it can detect hepatitis C (HCV) up to 57 days earlier than current tests.
On Sept. 21, Alpha announced the approval of this highly sensitive test to screen plasma donations for HIV and HCV. The test utilizes polymerase chain reaction (PCR), a highly sensitive test that can detect small amounts of DNA or RNA in blood or tissue samples by amplifying the existing DNA/RNA. This amplification technique allows the DNA or RNA to be detected more easily.
On May 16, 2000, Alpha obtained the U.S. patent for the "efficient algorithm method," which is used in concert with PCR technology to identify viruses in plasma. PCR testing is complex and difficult to apply to the millions of plasma donations collected each year. To simplify this procedure, Alpha utilizes this new method in which samples of 512 donations are pooled and tested by PCR.
When a sample pool tests positive, the efficient algorithm method is applied. Therefore, reactive samples can be detected with a minimum of 26 tests, instead of 512 tests needed to screen each sample. The efficient algorithm improves the detection and removal of reactive plasma donations and decreases the time that would otherwise be necessary for PCR testing.
PCR can identify very small amounts of the genetic material of the viruses. This test has the potential to identify a virus earlier in the process of infection, during the "window period," the time between primary infection and the appearance of antigens or antibodies against an organism, also known as seroconversion.
In addition to conducting scientific research, Alpha Therapeutic Corporation produces plasma-derived products and collects plasma donations throughout the U.S. The plasma donations are screened for HIV and hepatitis viruses with serologic tests approved by the FDA. These tests detect either antigens (any agent or substance that stimulates an immune response) or antibodies produced by the body in response to infection.
The company then processes the plasma into different products for the treatment of life-threatening conditions such as intravenous immune globulin (a type of antibody that provides specific humoral immunity against bacteria and viruses) for the treatment of primary immune deficiencies, coagulation factors for hemophilia and albumin (a protein found in bodily tissues and fluids; the principal protein in blood plasma) for shock, burns and trauma.
This article was provided by AIDS Project Los Angeles. It is a part of the publication Positive Living.