||Mycobacterium Tuberculosis ELISA IgG, IgM, IgA Assay (Serum/Plasma).
|# of Samples
||1 x 96 well.
||The GenWay Biotech, Inc. Mycobacterium tuberculosis (TB) ELISA IgG, IgM, IgA Assay system is an enzyme-linked immunosorbent assay (ELISA) designed for the presumptive qualitative detection of IgG, IgM and IgA antibodies to TB in human serum and for the presumptive diagnosis of acute, recent, or reactive TB infection. To adequately assess the patient's serological status, testing must be performed in conjunction with any of the other traditional TB diagnostic technologies.
||The Mycobacterium tuberculosis belongs to the genus Mycobacterium, which are aerobic, non-motile, and rod-shaped bacteria with two distinguishing characteristics: acid-fastness and slow growth.
Mycobacterium tuberculosis is one of most successful pathogens of mankind, infecting one-third of the global population and claiming two million lives every year. The ability of the bacteria to persist in the form of a long-term asymptomatic infection, referred to as latent tuberculosis, is central to the biology of the disease.
Approximately eight million people develop active tuberculosis (TB) every year, with two million dying from the disease. In addition to this already huge burden of disease, it is estimated that up to two billion people have been infected with the causative agent, Mycobacterium tuberculosis. Most people control the initial infection by mounting a cell-mediated immune response that prevents disease but can leave a residual population of viable mycobacteria. Between 5 - 10% of individuals who become infected subsequently develop clinical disease. Primary TB develops within 1 or 2 years after an initial infection and, particularly in children, is often associated with disseminated disease. Post-primary TB develops later in life, and can be caused either by reactivation of bacteria remaining from the initial infection or by failure to control a subsequent reinfection. Post-primary TB is predominantly a pulmonary disease, involving extensive damage to the lungs and efficient aerosol transmission of bacteria. The risk of disease is highly dependent on the immune status of the host; coinfection with HIV markedly increases the incidence of both forms of disease.
Currently, latent infection is diagnosed in a non-immunized person by a tuberculin skin test, which yields a delayed hypersensitivity type response to an extract made from M. tuberculosis. Those immunized for TB or with past-cleared infection will respond with delayed hypersensitivity parallel to those currently in a state of infection, so the test must be used with caution, particularly with regard to persons from countries where TB immunization is common. Tuberculin tests have the disadvantage in that they may produce false negatives, especially when the patient is co-morbid with sarcoidosis, Hodgkins lymphoma, malnutrition, or most notably active tuberculosis disease. New TB tests are being developed that offer the hope of a less expensive, fast and more
accurate TB testing. These use polymerase chain reaction detection of bacterial DNA and antibody assays to detect the release of interferon gamma in response to mycobacteria. These tests are not affected by immunization, so generate fewer false positive results.
Unlike the Tuberculin skin test, the GenWay Biotech, Inc. Mycobacterium Tuberculosis ELISA IgG, IgM, IgA Assay (Serum/Plasma) will dectect HIV/TB coinfection and has no detectable cross reactivity with BCG vaccinations.
|Principles of the assay
||The GenWay Bio ELISA test system is designed to detect IgG, IgM, and IgA class antibodies to TB in human sera. Wells of plastic microwell strips are sensitized by passive absorption with TB composite antigen. The antigen composite is a combination of recombinant proteins and fractionated Mycobacterium components.The test procedure involves three incubation steps
- Test sera (properly diluted) are incubated in antigen coated microwells. Any antigen specific antibody in the sample will bind to the immobilized antigen. The plate is washed to remove unbound antibody and other serum components.
- Peroxidase Conjugated Goat anti-Human IgG (μ-chain specific), Peroxidase Conjugated Goat anti-Human IgM (μ-chain specific) or Peroxidase Conjugated Goat anti-Human IgA (μ-chain specific) is added to the wells and the plate is incubated. The Conjugate will react with IgG, IgM or IgA antibody immobilized on the solid phase in step 1. The wells are washed to remove unbounded Conjugate.
- The microwells containing immobilized peroxidase Conjugate are incubated with TMB Peroxidase Substrate. Hydrolysis of the Substrate by peroxidase produces a color change. After a period of time the reaction is stopped and the color intensity of the solution is measured photometrically. The color intensity of the solution depends upon the antibody concentration in the original test sample.
|Storage and Stability
- Store the unopened kit between 2°C-8°C (with the exception of the 20X Wash Buffer concentrate which should be removed from the kit and stored at room temperature).
- Coated microwell strips: Store between 2°C-8°C. Extra strips should be immediately resealed with desiccant and returned to proper storage.
- Conjugate: Store between 2°C-8°C. DO NOT FREEZE.
- Positive Control and Negative Control: Store between 2°C-8°C.
- TMB Peroxidase Substrate: Store between 2°C-8°C.
- Wash Buffer concentrate (20X): Store between 15-25°C. Diluted wash buffer (1X) should be stored between 2°C-8°C.
- Specimen Diluent. Store between 2°C-8°C.
- Stop Solution: Store between 2°C-8°C.
|Limitation of the Test
- A diagnosis should not be made on the basis of anti-TB results alone. Test results for anti-TB should be interpreted in conjunction with the clinical evaluation and the results of other diagnostic procedures.
- The use of hemolytic, lipemic, bacterially contaminated or heat inactivated specimens should be avoided. Erroneous results may occur.
- A diagnosis should not be made on the basis of anti-EA results alone.
- The assay performance characteristics have not been established for matrices other than sera.
- The magnitude of the measured result above the cut-off is not indicative of the total amount of antibody present.
- Assay performance characteristics have not been established for visual result determinations.
- Caution should be used when evaluating samples obtained from immunosuppressed patients.