Search results
Results From The WOW.Com Content Network
An antibody titer is a measurement of how much antibody an organism has produced that recognizes a particular epitope. It is conventionally expressed as the inverse of the greatest dilution level that still gives a positive result on some test. ELISA is a common means of determining antibody titers.
In medical diagnosis, test sensitivity is the ability of a test to correctly identify those with the disease (true positive rate), whereas test specificity is the ability of the test to correctly identify those without the disease (true negative rate). If 100 patients known to have a disease were tested, and 43 test positive, then the test has ...
The complement fixation test is an immunological medical test that can be used to detect the presence of either specific antibody or specific antigen in a patient's serum, based on whether complement fixation occurs. It was widely used to diagnose infections, particularly with microbes that are not easily detected by culture methods, and in ...
In immunology the particular macromolecule bound by an antibody is referred to as an antigen and the area on an antigen to which the antibody binds is called an epitope. In some cases, an immunoassay may use an antigen to detect for the presence of antibodies, which recognize that antigen, in a solution.
Blood compatibility testing is routinely performed before a blood transfusion.The full compatibility testing process involves ABO and RhD (Rh factor) typing; screening for antibodies against other blood group systems; and crossmatching, which involves testing the recipient's blood plasma against the donor's red blood cells as a final check for incompatibility.
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]
The eclipse period is a variable period starting from HIV exposure in which no existing test can detect HIV. The median duration of the eclipse period in one study was 11.5 days. The window period is the time between HIV exposure and when an antibody or antigen test can detect HIV. The median window period for antibody/antigen testing is 18 days.
For the detection of HIV antibodies, the wells of microtiter plate are coated with the HIV antigen. Two specific antibodies are used, one conjugated with enzyme and the other present in serum (if serum is positive for the antibody). Cumulative competition occurs between the two antibodies for the same antigen, causing a stronger signal to be seen.