EUROIMMUN Radioimmoassays (RIA/IRMA)
Test principle RIA (precipitation techniques)
- In the first incubation step patient sera are incubated with 125I-labelled antigen in polystyrene tubes. Any specific antibodies in the sera bind to the antigen.
- In the second incubation step the antigen-antibody complexes are precipitated using a precipitation agent.
- The precipitate is washed with buffer. After centrifugation and decanting of the supernatant, the radioactivity in the precipitate is counted using a gamma counter. The intensity of the radioactivity is proportional to the concentration of specific antibody in the patient serum.
- The antibody concentration is evaluated quantitatively using a calibration curve.
Test principle RIA (coated tubes)
- RIA tests (coated tubes) are competitive ligand assays for antibody and antigen determinations.
- The intensity of radioactive radiation is inversely proportional to the concentration of specific antibodies or antigens in the sample.
- The quantitative evaluation of the antigen/antibody concentration is carried out using a calibration curve.
Test principle IRMA (antigen determination)
- With this test principle, monoclonal antibodies which are bound directly or indirectly to the inner wall of polystyrene tubes are used.
- During the first incubation step, the patient sera to be investigated are incubated with the monoclonal 125I-labelled antibodies in the coated tubes.
- The antigen in the sample is bound by the immobilised antibodies and by the 125I-labelled antibodies. This results in a solid-phase bound sandwich complex.
- The unbound 125I-labelled antibodies are removed by washing and subsequently decanting. The intensity of radioactive radiation is proportional to the concentration of antigens in the patient serum.
- The quantitative evaluation of the antigen concentration is carried out using a calibration curve.
Simple and economical handling, reliable analysis
- Simple and economical handling, reliable analysis
- Simple test procedure.
- Synchronous processing of samples, including different tests in parallel.
- Ready-to-use reagents (possible exceptions: tracer, precipitation reagents).
- Different test formats for small and large sample series.
- Because of the large measurement range of EUROIMMUN RIA, further measurements with other sample dilutions are generally not necessary.
- Simple evaluation of test results.
- Each test can be optionally evaluated with controls which are supplied in the test kit. Test kit-specific reference ranges are given for all controls.
- EUROIMMUN radioimmunoassays show the following analytical characteristics:
– High analytical specificity.
– High detection sensitivity.
– High clinical sensitivity and specificity.
– Good reproducibility.