Studies Confirm PCR's Value in Plasma Testing

A study has shown that investigational polymerase chain reaction (PCR) testing helped identify 706 viral traces of hepatitis B, hepatitis C, and HIV-1 in 4.1 million plasma donations previously testing negative by current plasma tests. In a second study involving a PCR in-process test on more than one million plasma donations, 11 donations tested positive for hepatitis A virus and 82 tested positive for parvovirus B19.

Investigational PCR screening, a form of nucleic acid testing (NAT), is designed to directly detect very low levels of viruses. The studies suggest that PCR technology may allow the detection of viruses in plasma at an earlier stage than more-commonly used screening methods, such as serology screening, says Aventis Behring, a division of Aventis S.A. (Strausbourg, France).

Aventis Behring's patented pasteurization process involves heating the products in solution for 10 hours at 600 C. Nanofiltration strains out viruses and allows plasma proteins to pass through this part of the manufacturing process unharmed. Immunoaffinity chromatography is an advanced purification technique used by Aventis Behring to reduce unwanted plasma proteins and viruses. The company uses the Cohn-Oncley ethanol fractionation method to further eliminate viruses. Additional chemicals, such as sodium thiocyanate, are also employed to inactivate viruses.

"The data suggest that this test may be of assistance in detecting the presence of viruses in plasma donations previously testing negative by current standards,” said Dr. Fred Feldman, vice president and chief scientist, research and development, Aventis Behring.



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