1. Trust is good, control is better!
Matthias Gessner
Baxter AG
Vienna, Austria

2. Background
71 HCV and 59 HIV commercially available quantified virus preparations were obtained from various vendors and tested with HIQ-PCR
Testing in various dilutions by HIQ-PCR in frame of performance study
11 samples (8%) gave unexpected negative results in the test, i.e. were not detected in spite of a nominally high concentration in the sample
These samples were sent to the Inst. of Virology, Medical Univ. of Vienna for independent quantitative testing
Cobas Amplicor HCV Monitor v2.0
Cobas Amplicor HIV-1 Monitor v1.5

3. Viral load according to

4. Conclusion
Specimens yielding negative or unexpectedly low results showed gross deviation between their stated and actual viral load when re-quantified
Since only samples with very obvious deviations were re-tested, the percentage of commercially available samples with deviating concentration values may be higher
Quantitative information provided with commercially available viral specimens, such as
Clinical samples
Viral preparations
Seroconversion panels
may by misleading and thus, needs to be regarded with caution.