Evaluation of microparticle enzyme immunoassays for immunoglobulins G and M to rubella virus and Toxoplasma gondii on the Abbott IMx automated analyzer

Schaefer, Lawrence; Dyke, J.W. Van; Meglio, Franklin D.; Murray, Patrick R.; Crafts, W; Niles, A C

doi:10.1128/jcm.27.11.2410-2413.1989

Cited by 26 publications

(12 citation statements)

References 23 publications

(14 reference statements)

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“…Despite the fact that false-positive results in tests for IgM toxoplasma antibodies have been described (1,8,13,29,30), the majority of studies on tests for IgM antibodies report high specificities (3,9,16,19,25,26) (summarized in Table 3). Thus, one might conclude that such false-positive results are infrequent and therefore of little consequence.…”

Section: Discussionmentioning

confidence: 99%

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False-positive results in immunoglobulin M (IgM) toxoplasma antibody tests and importance of confirmatory testing: the Platelia Toxo IgM test

et al. 1997

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Although tests for detection of immunoglobulin M (IgM) toxoplasma antibodies have been reported to have a high degree of accuracy, it is well recognized by investigators in the United States and Europe that false-positive results may occur with many of these tests, at times to an alarming degree. Unfortunately, this information is not well documented in the literature. Studies on various toxoplasma IgM test kits are frequently flawed. The investigators often use reference tests which have not previously been carefully evaluated as well as sera that were not appropriate to answer the question of how often false-positive results might occur. We recently had the unique opportunity to evaluate the accuracy of the Platelia Toxo IgM test in 575 serum samples obtained during an outbreak of toxoplasmosis which occurred in 1995 in the Capital Regional District of British Columbia, Canada. When compared with results obtained in a reference IgM enzyme-linked immunosorbent assay (ELISA), the Platelia Toxo IgM test had a sensitivity of 99.4%, specificity of 49.2%, positive predictive value of 51.9%, negative predictive value of 99.3%, and an overall agreement of 67.0%. In an attempt to resolve discrepancies between these two tests, a serological profile (Sabin-Feldman dye test, IgA and IgE antibody tests, differential agglutination [AC/HS] test, and IgG avidity method) was performed. Of 153 serum samples that were positive in the Platelia Toxo IgM test and negative in the IgM ELISA, 71 (46.4%) were negative in the Sabin-Feldman dye test. Of the serum samples that were positive in the dye test, 77 (93.9%) had a serological profile most compatible with an infection acquired in the distant past. These results reveal high numbers of false-positive results in the Platelia Toxo IgM test and highlight the importance of appropriate evaluation of commercial tests that are currently being marketed. Our results also emphasize the importance of confirmatory testing to determine whether the results of an IgM antibody test reflect the likelihood of a recently acquired infection.

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Section: Discussionmentioning

confidence: 99%

“…Commercial kits for detection of toxoplasma IgM antibodies are increasingly being used. The majority of studies on IgM toxoplasma antibody tests have reported that they are highly accurate (3,9,11,16,19,25,26). Others, however, have reported high numbers of false-positive and false-negative results (1,8,13,29,30).…”

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confidence: 99%

False-positive results in immunoglobulin M (IgM) toxoplasma antibody tests and importance of confirmatory testing: the Platelia Toxo IgM test

et al. 1997

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“…IMx and Vidas are two of the most widely used methods for the detection of anti-Toxoplasma antibodies in French laboratories. There have been very few reports in which IMx first or second generation was used (11,12). The method adopted in our study differs in several respects from those described elsewhere (5,(13)(14)(15)(16)(17)(18)(19).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the second generation IMx Toxo IgG antibody assay for detection of antibodies toToxoplasma gondii in human sera

Champs

Pelloux

Cambon³

et al. 1997

J. Clin. Lab. Anal.

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For an evaluation of the Abbott Imx Toxo IgG second generation, antibodies to Toxoplasma gondii were detected by Abbott Imx Toxo IgG and IgM, Vidas Toxo IgG and Toxo IgM (bioMérieux, France) with immunofluorescence assay verified by the dye‐test for IgG, and immunosorbent agglutination assay (ISAGA) for IgM as references. The study included 507 serum samples collected over one month in two laboratories, 32 samples from HIV‐infected patients, and 70 serial samples from 23 women surveyed for seroconversion or persistent IgM. After exclusion of nine equivocal results from the 507 samples, the sensitivity and specificity, respectively, were 100% (156/156) and 100% (342/342) for the Imx Toxo IgG and 98.1% (153/156) and 100% (342/342) for the Vidas Toxo IgG. Of the 32 HIV‐infected patient samples, 7 gave false positive results with Imx Toxo IgG. This was because the samples had been heated. In 5 of the 70 serial samples, Imx Toxo IgG gave positive results earlier than Vidas Toxo IgG and in two cases earlier than IgM antibody assays. In this study Imx Toxo IgG second generation showed an increase in sensitivity and specificity in comparison with data reported previously for the first generation. J. Clin. Lab. Anal. 11:214–219, 1997. © 1997 Wiley‐Liss, Inc.

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“…Previous studies on the fully automated IMx rubella IgG assay have shown that the system is more sensitive than and as specific as conventional EIA technology. 16,18 Schaefer et al 8 showed that the IMx had a sensitivity of 99.9% compared to a sensitivity of 96.5 % for Rubazyme. Specificity was identical for both assays at 98.9%.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Five Methods for the Determination of Rubella Immunity

Sautter

Crist

Johnson

et al. 1994

Infectious Diseases in Obstetrics and Gynecology

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Objective: The purpose of this study was to compare the accuracy of commonly used methods for the detection of rubella immunity, especially the fully automated IMx assay. Methods: A total of 190 sera (101 immune and 89 non-immune) submitted to Harrisburg Hospital or Polyclinic Medical Center for the determination of rubella immunity were tested by enzyme immunoassay (IMx and Rubazyme, Abbott Diagnostic Laboratories, North Chicago, IL), indirect immunofluorescence (FIAX, Whittaker Bioproducts, Walkersville, MD), and latex agglutination (Rubascan, Becton Dickinson Microbiology Systems, Cockeysville, MD, and Rubalex, Wellcome Diagnostics, Research Triangle Park, NC). Specimens were frozen at –30℃ until the study was initiated. Each of the assays was performed according to the manufacturers' specifications. Sensitivity, specificity, accuracy, and positive and negative predictive values for each assay were calculated using a consensus result of the 5 methods tested. Results: The sensitivity, specificity, and accuracy, respectively, of the test systems were as follows: IMx, 96%, 97%, and 96%; Rubazyme, 100%, 99%, and 99%; Rubascan, 100%, 98%, and 99%; Rubalex, 99%, 97%, and 98%; and FIAX 90%, 100%, and 95%. False negative reactions were seen with the FIAX system. Conclusions: The IMx system, a new “walk away” system from Abbott Diagnostic Laboratories and the Rubazyme systems performed well; however the latex agglutination tests proved to be the most rapid and convenient methods for screening sera for the presence of rubella immunity.

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Evaluation of microparticle enzyme immunoassays for immunoglobulins G and M to rubella virus and Toxoplasma gondii on the Abbott IMx automated analyzer

Cited by 26 publications

References 23 publications

False-positive results in immunoglobulin M (IgM) toxoplasma antibody tests and importance of confirmatory testing: the Platelia Toxo IgM test

False-positive results in immunoglobulin M (IgM) toxoplasma antibody tests and importance of confirmatory testing: the Platelia Toxo IgM test

Evaluation of the second generation IMx Toxo IgG antibody assay for detection of antibodies toToxoplasma gondii in human sera

Comparison of Five Methods for the Determination of Rubella Immunity

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