Chiron ( CHIR) said Thursday that the Food and Drug Administration approved its Procleix blood testing system for early detection of a type of HIV and hepatitis C. Approval of Procleix was expected at the end of last year, but some quality control issues caused a delay. It could have been worse -- some analysts and blood-banking officials had predicted a delay of up to six months. Procleix, also known as the nucleic acid amplification test, is a super-sensitive screening method that detects at a very early stage the presence of Type 1 HIV and Hepatitis C viruses in donated blood. The system detects these viruses before they would be picked up by other blood-screening methods. Procleix is already used to screen about 70% of the U.S. blood donations, but until FDA approval, Chiron was only allowed to sell the test at cost. Chiron was up $1.59, or almost 4%, to $43.22 per share, in recent trading.