Nucleic acid amplification technology for hepatitis B virus, and its role in blood donation screening in blood banks

To investigate the performance of hepatitis B virus polymerase chain reaction [HBV PCR] using one of the commercial methods used around the world to screen for HBV in some blood donors where other conventional serological assays have limitations to detect the virus. This study was designed to use Amplicor AmpliScreen for HBV testing to detect the presence of the HBV DNA in the specimens tested by COBAS AmpliPrep[TM] system using a modified manufacture protocol COBAS AmpliPrep of total nucleic acid isolation [TNAI] kit. All serological tests were carried out on the donors' samples to detect the hepatitis B surface antigen [HBsAg], Australian antibody anti-HBs [AUSAB] and hepatitis B core antigen [HBcAg] in the 2 periods of the study. The first period was started in February 2005 and the second period was started in April 2007. Both periods were continued for 2 months after beginning in the molecular pathology laboratory, Al-Hada Armed Forces Hospital, Taif, Kingdom of Saudi Arabia. The 600 donors' data were then studied and analyzed. Five nucleic acid amplification test [NAT-HBV] positives were found out of 600. There were 3 positive for HBcAb and negative for HBsAg, 2 had reading with <100 mIU/mL anti-HBs [AUSAB], and one had >100 mIU/mL AUSAB readings. Our results show that there is a possibility to have "occult" HBV infection in some donors that cannot be detected by the HBsAg routine serological assays. Moreover, the study can be useful to formulate a new deferral policy based on the implementation of NAT-HBV for blood screening

Nucleic acid amplification technology Screening for hepatitis C virus and human immunodeficiency virus for blood donations

To investigate the performance of the commercial Roche COBAS AmpliScreen assay, and demonstrate whether the COBAS AmpliScreen human immunodeficiency virus-1 [HIV-1] test, v1.5, and COBAS AmpliScreen hepatitis C virus [HCV] v 2.0 for screening for HIV-1 and HCV RNA in the donated blood units from which plasma mini pools were collected, by nucleic acid amplification technology [NAT], could detect the positive pools and reduce the risk of transmission of infections for those routinely tested by serological assays. The study was performed on 3288 plasma samples collected from blood donors in a period of 13 months, from August 2004 to August 2005, at Al-Hada Armed Forces Hospital, Molecular Pathology Laboratory, Taif, Kingdom of Saudi Arabia. The samples were tested by the reverse transcriptase polymerase chain reaction [RT-PCR] after RNA extraction [this represents the major method in NAT assays], in parallel with the routine serological testing to detect qualitatively for HIV-1 and HCV. The NAT assays that include an automated COBAS AmpliPrep system for RNA extraction and COBAS Amplicor Analyzer using AmpliScreen kits for RT-PCR assays, and the routine serological screening assays for the detection of the HIV-1 and HCV RNA in the plasma samples from the blood donors have shown to be a reliable combination that would meet our requirements. The collected data further confirms the results from the serological assays and enables us to decrease the residual risk of transmission to a minimum with the finding of no seronegative window period donation. The results demonstrate that out of 3288 samples, the percentages of RT-PCR [NAT] negative blood donations that were also confirmed as seronegative were 99% for HCV, and 99.1% for HIV-1. The modified combined systems [automated COBAS AmpliPrep system for RNA extraction and COBAS Amplicor Analyzer using AmpliScreen kits for RT-PCR assays] for NAT screening assays has allowed the release of all blood donations supplied in the specified period of the study with no seronegative window period donations. This facilitates keeping the residual risk of transmission of HIV-1 and HCV to its minimum through blood transfusion