[The confusing diversity of IgM tests in the diagnosis of Toxoplasma infections: efforts towards an optimal strategy].
IgM antibodies are indicative for a recent infection, thus the detection of this isotype is of essential significance particularly in the diagnosis of infections with Toxoplasma gondii during pregnancy (primary infection, seroconversion). Numerous serological tests and test kits (e.g. indirect immunofluorescent assay/IFAT, enzyme-linked immunosorbent assay/ELISA, Immunosorbent agglutination assay/ISAGA, Westernblot/WB) using different antigens and antigen preparations are provided by numerous companies. The sensitivities of such tests, however, variy considerably: The serological test results of four pregnant women with seroconversions and of three newborns from mothers with seroconversions are presented: VIDAS M and ISAGA M from one company yielded false negative results in three pregnant women whereas ISAGA M from another company could detect specific IgM. However, examination of the cord blood of the three newborns unanimously revealed IgM-negative results. Thus, our diagnostic strategy for pregnant women includes IIFT (or SFT) as basic test and ISAGA M (Toxotool I from Innogenetics) as well as IgG avidity test as additional tests; the serological diagnosis of suspected congenital infection comprises IFAT (or SFT), ISAGA M (from Innogenetics) and IgM/IgG Westernblot.
Auer
Herbert
H
Abteilung für Medizinische Parasitologie, Klinisches Institut für Hygiene und Medizinische Mikrobiologie der Universität Wien. herbert.auer@univie.ac.at
Vander-Möse
Angelika
A
Aspöck
Horst
H
D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood*; D007231:Infant, Newborn; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000295:instrumentation* / Q000379:methods*; D014123:Toxoplasmosis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*
D007075:Immunoglobulin M