Hi again,
HCV screening at blood banks usually consists of testing for presence of antibodies; these are harmless proteins produced by our own immune response to a pathogen, in this case HCV.
Antibody results are either ‘reactive’ (positive) or non-reactive (negative). A reactive result only indicates possible exposure, but not necessarily presence of active, RNA virus. Antibody testing is set up to inexpensively screen large pools of people, and is subject to false positive results. This necessitates further, confirmatory testing.
Additionally, even if the antibody result is truly positive, and the patient was indeed exposed in the past, 15-2-% of patients will clear the virus with the aid of their own immune response in the initial six months of infection. In this case, they will continue to test positive for antibodies for life, but do not carry the active virus.
The HCV RNA by PCR test is a nucleic acid test that checks for presence of active virus, as opposed to antibody results.
Tx is an acronym for ‘treatment’:
http://www.medhelp.org/health_pages/Hepatitis/Common-Hepatitis-C-Acronyms/show/3?cid=64
Welcome to the discussion group,
Bill