AXSYM TOXO IGM

{0} Abbott Laboratories AxSYM Toxo IgM Antibody Assay [510(k)] Submission K954576 AUG 23 1996 ATTACHMENT A [510(k)] Summary Of Safety And Effectiveness Information Supporting A Substantially Equivalent Determination ATTACH-A Page 1 of 4 0038 {1} Abbott Laboratories AxSYM Toxo IgM Antibody Assay [510(k)] Submission # [510(k)] Summary Of Safety And Effectiveness Information Supporting A Substantially Equivalent Determination The following information as presented in the [510(k)] notification for the AxSYM Toxo IgM assay constitutes data supporting a substantially equivalent determination: # [510(k)] Summary of Device Performance The AxSYM Toxo IgM assay is a Microparticle Enzyme Immunoassay (MEIA) for the qualitative measurement of IgM antibodies to Toxoplasma gondii in human serum and plasma (EDTA, heparin, or sodium citrate) to aid in the diagnosis of primary infection. The AxSYM Toxo IgM assay is not for use with cord blood or neonatal specimens. This product is not FDA cleared for use in testing blood or plasma donors. The predicate device for determination of substantial equivalence is the bioMerieux VIDAS Toxo-M. The VIDAS Toxo IgM (TXM) assay is intended for use with a VIDAS (Vitek ImmunoDiagnostic Assay System) instrument as an automated enzyme-linked fluorescent immunoassay (ELFA) for the qualitative detection of anti-Toxoplasma gondii IgM antibodies in human serum, as an aid in the diagnosis of toxoplasmosis. It is not intended for use in testing (screening) blood or plasma donors. In two U.S. sites and one European site, the AxSYM Toxo IgM assay was compared to the VIDAS Toxo IgM assay using 1,400 samples from pregnant women, non-pregnant individuals and individuals positive for IgM antibodies to T. gondii. Discordant results were resolved by testing with Platelia Toxo IgM (Sanofi) and Abbott IMx Toxo IgM Antibody assay, both of which are legally marketed devices in the United States. Based on this study, the AxSYM Toxo IgM assay showed relative sensitivity of 96.3%, relative specificity of 99.8% and relative agreement of 99.3%. Specimens giving equivocal results were not included in the calculation of relative agreement, relative sensitivity, or relative specificity. Percent CV's on positive panel members and positive control was 6.0% to 10.1%. In conclusion, the AxSYM Toxo IgM Assay is substantially equivalent to the VIDAS Toxo IgM assay for the detection of IgM antibodies to T. gondii in human serum and plasma (EDTA, heparin, or sodium citrate) specimens. ATTACH-A Page 2 of 4 0039 {2} Abbott Laboratories AxSYM Toxo IgM Antibody Assay [510(k)] Submission [510(k)] Summary Of Technological Comparison The AxSYM Toxo IgM Antibody assay and the bioMerieux VIDAS Toxo IgM are substantially equivalent in that: A. Both are in vitro immunologic test methods. B. Both are intended for use in the detection of IgM antibody to T. gondii in human serum. C. Both are based on information of immune complexes between T. gondii antigens and antibody. D. Both use a polystyrene solid phase. E. Both are qualitative assays. F. Both use automated immunoassay analyzers. G. Both use 4 methylumbelliferyl phosphate (MUP) as the enzyme substrate. The AxSYM Toxo IgM Antibody assay and the VIDAS Toxo IgM assay differ in that: A. The solid phase in the AxSYM Toxo IgM assay contains polystyrene microparticles coated with Toxoplasma gondii antigen. The VIDAS Toxo IgM assay is coated with goat anti-μ chain antibodies inside of the SPR (solid phase receptacle). B. The conjugate in the AxSYM Toxo IgM assay contains goat anti-human IgM antibody conjugated to alkaline phosphatase. The conjugate in the VIDAS Toxo IgM assay contains an immune complex of T. gondii antigen and anti-P30 mouse monoclonal antibody conjugated to alkaline phosphatase. C. Serum and plasma (EDTA, heparin, sodium citrate) specimens may be tested in the AxSYM Toxo IgM assay. The use of plasma specimens has not been validated in the VIDAS Toxo IgM Assay. D. The AxSYM Toxo IgM assay utilizes a rheumatoid neutralization buffer to remove rheumatoid factor interference antibodies. The VIDAS Toxo IgM assay does not utilize a buffer for rheumatoid factor interference antibodies. ATTACH-A Page 3 of 4 0040 {3} Abbott Laboratories AxSYM Toxo IgM Antibody Assay [510(k)] Submission # Comparison Of Methods | Assay Characteristic | AxSYM Toxo IgM Assay | VIDAS Toxo IgM Assay | | --- | --- | --- | | Assay Type | Qualitative | Qualitative | | Antibody Measured | Specific IgM | Specific IgM | | Assay Principle | MEIA | EIA (ELFA) | | Solid Phase | polystyrene microparticle | polystyrene solid phase receptacle | | Solid Phase Coating | Toxoplasma antigen, RH strain derived from HeLa cell culture | goat anti-μ chain antibodies | | Conjugate | goat anti-human IgM antibodies conjugated to alkaline phosphatase | mouse anti-P30 monoclonal antibody conjugated to alkaline phosphatase | | Specimen | Human serum and plasma (EDTA, heparin, citrate) | Human serum | | Automation | performed on an automated instrument | performed on an automated instrument | | Relative Specificity | 99.8% ( European & U.S. ) | 93.0% - 94.3% ( U.S. ) 99.4% - 99.6% ( European ) | | Relative Sensitivity | 96.3% ( European & U.S. ) | 87.9% - 99.5% ( U.S. ) 97.7% - 100.0% ( European ) | ATTACH-A Page 4 of 4 0041