Hepatitis C antibody is positive, the virus may not be detected in the following situations: experimental error, disease cure, hidden infection. 1. Experimental error: patients have not been infected with hepatitis C virus, due to the error of testing instrument, the contamination of test specimen, or patients take some drugs, as well as the influence of some other diseases, it may lead to false-positive hepatitis C antibody, but the patient’s body is not infected with hepatitis C virus, so it can not detect the virus. 2. Disease Cure: Hepatitis C patients have reached the clinical standard cure after regular and systematic clinical treatment, at this time, the virus replication is very little, it is possible that the virus can not be detected. However, due to the hepatitis C virus, the patient’s blood will be stimulated to produce hepatitis C antibody, which may exist for a long time, so there will be positive hepatitis C antibody. 3. Hidden infection: some patients have been exposed to hepatitis B virus, the virus enters the body and stimulates the body to produce hepatitis C antibody, but the body, through the immune mechanism, automatically clears the hepatitis C virus, which will result in the detection of hepatitis C antibody, resulting in hepatitis C antibody positive, but the situation of undetectable hepatitis C virus. When the above situation occurs, it is necessary to closely observe the condition of the body and, if necessary, repeat the test for hepatitis C antibody to keep abreast of the changes in the body.