Multiplex Method for Detecting an Infection

1 - 18 . (canceled)

19 . A method for the in vitro diagnostic detection of an infection with a microorganism comprising:

a) placing a biological sample, in a single assay receptacle, in the presence of particles, each carrying at least one specific detectable physical parameter, and belonging to at least two different groups, one of the groups carrying an anti-IgM capture antibody and the other group carrying a capture antigen derived from said microorganism,

b) incubating the mixture under conditions which allow the formation of immunocomplexes on each group of particles,

c) eliminating the immunoglobulins which have not bound to the particles,

d) incubating the mixture of step b) with at least one labelled conjugate, said at least one conjugate consisting exclusively of a detection antigen derived from said microorganism,

e) eliminating the detection antigen not bound to the immunocomplexes of step b), and

f) simultaneously detecting, by means of a detector capable of differentiating the two groups of particles mentioned above, the immunocomplexes of step d) on each particle, whereby the presence or absence of immunoglobulins G or total immunoglobulins and/or immunoglobulins M directed against said microorganism is revealed.

20 . The method according to claim 19 , wherein the antigen derived from the microorganism is selected from the group consisting of a lysate of said microorganism, one of its natural antigens that has been semi-purified or purified, a recombined protein, a fragment thereof and a synthetic peptide.

21 . The method according to claim 19 , wherein the groups of said particles differ from one another by virtue of fluorochromes, detectable by a suitable detector.

22 . The method according to claim 19 , in which the suitable detector is a flow cytometer.

23 . The method according to claim 19 , in which the detection antigen carries a biotin which is revealed by adding labelled avidin or labelled streptavidin.

24 . The method according to claim 19 , in which the biological sample is plasma or serum.

25 . The method according to claim 19 , in which the biological sample is of human origin.

26 . The method according to claim 19 , wherein said microorganism is selected from the group consisting of viruses, bacteria and single-cell parasites.

27 . The method according to claim 26 , wherein said microorganism is a human hepatitis virus.

28 . The method according to claim 27 , wherein said microorganism is a human hepatitis A virus (HAV) or a human hepatitis B virus (HBV).

29 . The method according to claim 28 , wherein said microorganism is the human hepatitis A virus (HAV) and a lower detection limit for total anti-HAV immunoglobulins of approximately 20 mIU/ml is obtained.

30 . The method according to claim 26 , characterized in that said microorganism is Treponema pallidum.

31 . The method according to claim 19 , in which the particles are superparamagnetic particles.

32 . A set of reagents for carrying out the detection method according to claim 19 , comprising particles, each carrying at least one specific detectable physical parameter, and belonging to at least two different groups, one of the groups carrying an anti-IgM capture antibody and the other group carrying a capture antigen derived from a microorganism to be detected.

33 . The set according to claim 32 , wherein said microorganism is selected from the group consisting of viruses, bacteria and single-cell parasites.

34 . The set according to claim 33 , wherein said microorganism is a human hepatitis virus.

35 . The set according to claim 34 , wherein said microorganism is a human hepatitis A virus (HAV) or a human hepatitis B virus (HBV).

36 . The set according to claim 33 , wherein said microorganism is Treponema pallidum.