Evaluation of the Bio-Rad BioPlex 2200 Toxoplasma gondii IgM Multiplex Flow Immunoassay

Abstract

Background Toxoplasmosis is routinely diagnosed through detection of Toxoplasma gondii–specific antibodies. However, the imperfect specificity of T. gondii serologic assays is a well-recognized limitation. The new BioPlex 2200 (Bio-Rad Laboratories) T. gondii, rubella, and cytomegalovirus (ToRC) IgM multiplex flow immunoassay (MFI) received FDA clearance in May 2017. We evaluated the clinical performance of the new T. gondii IgM and existing IgG portion of this MFI. Methods Three hundred prospectively collected consecutive, residual sera, submitted for T. gondii serologic testing as part of routine clinical care, and an archived set of 52 residual sera previously positive for anti–T. gondii IgM and IgG with the predicate ADVIA Centaur Toxoplasma IgM and IgG assays (Siemens) were evaluated. Performance of the BioPlex 2200 T. gondii IgM and IgG MFIs was assessed by calculating positive (PPA) and negative percent agreement (NPA) compared to the Centaur tests. Results Among prospective specimens, the BioPlex 2200 T. gondii IgM and IgG MFIs demonstrated a PPA of 0% (0/7) and 82.3% (28/34) and NPA of 99.3% (288/290) and 95.8% (251/262), respectively, with the Centaur assays. Chart review of the 7 Centaur T. gondii IgM-positive samples revealed that these were likely falsely positive. Among archived samples, the BioPlex 2200 T. gondii IgM and IgG MFIs showed PPAs of 90.4% (47/52) and 100% (52/52), respectively. Conclusions The BioPlex 2200 T. gondii IgM and IgG MFIs demonstrated excellent concordance with the Centaur assays. The T. gondii IgM MFI may provide higher specificity in low-prevalence populations.

Detection of Anti-Toxoplasma gondii Antibodies in Human Sera Using Synthetic Glycosylphosphatidylinositol Glycans on a Bead-Based Multiplex Assay

“…Therefore, each assay format has its own advantages and disadvantages. BBMA is suitable for diagnostic purposes in clinical settings, illustrated by the recently introduced commercial multiplex assay for the detection of IgM antibodies against T. gondii , rubella, and cytomegalovirus (ToRC) − or for large-scale epidemiological surveys. , We illustrate that the GPI 1 glycan antigen works independently of the type of assay used and can be applied for the detection of both IgG and IgM antibodies, which might be a valuable addition to established commercial assays. Further studies should determine the reactivity of IgA and IgE antibodies, and the avidity of IgG antibodies toward GPIs, which may extend the applicability of this antigen to confirm an acute infection also in other assay formats.…”

Frequency of Toxoplasma gondii, Rubella, and Cytomegalovirus Antibodies in Pregnant Women in Yazd Province, Iran

“…Therefore, these women should avoid eating undercooked meat, contact with soil, unwashed fruits and vegetables, and contact with stray cats (8). Some techniques have been consistently used for the serology diagnosis of acute infections of toxoplasmosis, such as the BioPlex 2200 immunoglobulin G (IgG) assay, among others (19)(20)(21)(22)(23).…”