The second contained incomplete antibody and showed titers of 1: 256 in albumin and 1: 2048 by the indirect Coombs test.

* General antibody screen ( indirect Coombs test ) for HDN

Treponema pallidum is also detected by serology, including nontreponemal VDRL, rapid plasma reagin ( RPR ) and treponemal antibody tests ( FTA-ABS ), Treponema pallidum immobilization reaction ( TPI ) and syphilis TPHA test ).

A direct antiglobulin test ( Coombs test ) is also performed as part of the antibody investigation .< ref >

* The primary antibody is added, which binds specifically to the test antigen coating the well.

The color change shows the secondary antibody has bound to primary antibody, which strongly implies the donor has had an immune reaction to the test antigen.

The sandwich or direct ELISA provides a solution to this problem, by using a " capture " antibody specific for the test antigen to pull it out of the serum's molecular mixture.

Because the ELISA can be performed to evaluate either the presence of antigen or the presence of antibody in a sample, it is a useful tool for determining serum antibody concentrations ( such as with the HIV test or West Nile virus ).

Similar symptoms can be caused by cytomegalovirus, adenovirus, and Toxoplasma gondii, but will result in a negative heterophile antibody test.

Only half the patients presenting with the symptoms held by mononucleosis and a positive heterophile antibody test ( monospot test ) meet the entire criteria.

A few studies on infectious mononucleosis have been conducted in a primary care environment, the best of which studied 700 patients, of which 15 were found to have mononucleosis upon a heterophile antibody test.

In the past, the most common test for diagnosing infectious mononucleosis was the heterophile antibody test, which involves testing heterophile antibodies by agglutination of guinea pig, sheep and horse red blood cells.

However, when positive, they feature similar sensitivities to the heterophile antibody test.

Therefore, these tests are useful for diagnosing infectious mononucleosis in people with highly suggestive symptoms and a negative heterophile antibody test.

* Direct agglutination test, any test that uses whole organisms as a means of looking for serum antibody

* The confirmatory HIV test employs a western blot to detect anti-HIV antibody in a human serum sample.

One can test noninvasively for H. pylori infection with a blood antibody test, stool antigen test, or with the carbon urea breath test ( in which the patient drinks < sup > 14 </ sup > C-or < sup > 13 </ sup > C-labelled urea, which the bacterium metabolizes, producing labelled carbon dioxide that can be detected in the breath ).

There are a number of diagnostic tests for including: HCV antibody enzyme immunoassay or ELISA, recombinant immunoblot assay, and quantitative HCV RNA polymerase chain reaction ( PCR ).

Performing an ELISA involves at least one antibody with specificity for a particular antigen.

The sample with an unknown amount of antigen is immobilized on a solid support ( usually a polystyrene microtiter plate ) either non-specifically ( via adsorption to the surface ) or specifically ( via capture by another antibody specific to the same antigen, in a " sandwich " ELISA ).

Some competitive ELISA kits include enzyme-linked antigen rather than enzyme-linked antibody.

Human anti-IgG, double antibody sandwich ELISA

Like the ELISA procedure, the western blot is an antibody detection test.

ELISA testing alone cannot be used to diagnose HIV, even if the test suggests a high probability that antibody to HIV-1 is present.

The ELISA antibody tests were developed to provide a high level of confidence that donated blood was NOT infected with HIV.

It is therefore not possible to conclude that blood rejected for transfusion because of a positive ELISA antibody test is in fact infected with HIV.

Sometimes, retesting the donor in several months will produce a negative ELISA antibody test.

: HIV antibody tests are highly sensitive, meaning they react preferentially with HIV antibodies, but not all positive or inconclusive HIV ELISA tests mean the person is infected by HIV.

The syphilis anti-cardiolipin antibodies are beta-2 glycoprotein independent, whereas those that occur in the antiphospholipid antibody syndrome ( associated to lupus for example ) are beta-2 glycoprotein dependent, and this can be used to tell them apart in an ELISA assay.

Quantification of viral load can be determined by Plaque Assay, antigen capture enzyme immunoassay ( EIA ), ELISA and HA, and quantification of antibody levels by HAI and Neutralisation assay.

A wide range of cellular secretions ( say, a specific antibody or cytokine ) can be detected using the ELISA technique.

There it is detected with ELISA technique: The wells are filled with a solution of a monoclonal antibody to bromo-deoxyuridine.

Frequently used serological tests include antibody tests, ELISA and indirect hemaglutination ( IHA ).

The introduced mouse will seroconvert, allowing use of immunofluorescence antibody ( IFA ), MFIA or ELISA to detect antibodies.

Antibodies to IBV may be detected by indirect immunofluorescent antibody test, ELISA and Haemagglutination inhibition ( haemagglutinating IBV produced after enzymatic treatment by phospholipase C ).

Virus isolation, increased antibody titres, immunoperoxidase staining, ELISA, PCR or indirect immunofluorescence can be used to confirm the presence of the virus.

* Blocking in western blot, a process to prevent unwanted binding of antibody to the membrane

The colorimetric detection method depends on incubation of the western blot with a substrate that reacts with the reporter enzyme ( such as peroxidase ) that is bound to the secondary antibody.

Chemiluminescent detection methods depend on incubation of the western blot with a substrate that will luminesce when exposed to the reporter on the secondary antibody.

Its name derives from the fact that it directly tests the presence of an antigen with the tagged antibody, unlike western blotting, which uses an indirect method of detection, where the primary antibody binds the target antigen, with a secondary antibody directed against the primary, and a tag attached to the secondary antibody.

These tags are particularly useful for western blotting, immunofluorescence and immunoprecipitation experiments, although they also find use in antibody purification.