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.

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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.

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