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[5] [70] Therefore, a positive antibody test may not imply immunity to a future infection. Further, whether mild or asymptomatic infections produce sufficient antibodies for a test to detect has not been established. [71] Antibodies for some diseases persist in the bloodstream for many years, while others fade away. [56]
These self tests don’t detect antibodies that would indicate ... a PCR test can rarely be a false positive, says Dr. Watkins, but “in an asymptomatic person without known close contact with an ...
Antigen tests can be analyzed within a few minutes. Antigen tests are less accurate than PCR tests. It has a low false positive rate, but a higher false negative rate. A negative test result may require confirmation with a PCR test. [8] Advocates claim that antigen tests are less expensive and can be scaled up more rapidly than PCR tests. [8]
Both types of antibodies are measured when tests for immunity are carried out. [9] Antibody testing has become widely available. It can be done for individual viruses (e.g. using an ELISA assay) but automated panels that can screen for many viruses at once are becoming increasingly common. [citation needed]
Others lead to antibodies that the immune system only produces for a few weeks following resolution. After seroreversion, tests can no longer detect antibodies in a patient's serum. [14] The immune system generates antibodies to any antigen, so seroconversion can occur as a result of either natural infection or as a result of vaccination.
The test is usually performed using commercially available test kits which detect the reaction of heterophile antibodies in a person's blood sample with horse or cow red blood cell antigens. These test kits work on the principles of latex agglutination or immunochromatography. Using this method, the test can be performed by individuals without ...
Alternatively, T. cruzi DNA can be detected by polymerase chain reaction (PCR). In acute and congenital Chagas disease, PCR is more sensitive than microscopy, [25] and it is more reliable than antibody-based tests for the diagnosis of congenital disease because it is not affected by the transfer of antibodies against T. cruzi from a mother to ...
Nonspecific reactions, hypergammaglobulinemia, or the presence of antibodies directed to other infectious agents that may be antigenically similar to HIV can produce false positive results. Autoimmune diseases, such as systemic lupus erythematosus, have also rarely caused false positive results. Most false negative results are due to the window ...