Table. 1.

Basic characteristics of Ab assays provided by manufacturers

Assay Cutoff value Unit Principle Capture Ag/Ab (solid phase) Label (reporter) Interference or specificity for other condition

NR GZ R Tested no. Reactive no. Detail (no.)
Toxo IgM* <0.50 0.50–0.60 ≥0.60 Index CMIA Anti-human IgM (mouse, monoclonal) Ab Acridinium-labeled anti-Toxo p30 Ag mouse monoclonal F(ab')2 fragment and native Toxoplasma gondii lysate 167 (Unspiked); 165 (spiked) 2 (Unspiked); 10 (spiked) R/GZ (1/1): ANA; false R (8): polyclonal IgM; false GZ (2): poly- & mono-clonal IgM
Rubella IgM <1.20 1.20–1.60 ≥1.60 Index CMIA Rubella whole virus (strain HPV 77) Anti-human IgM (murine) acridinium-labeled conjugate NA NA NA
CMV IgM <0.85 0.85–1.00 ≥1.00 Index CMIA CMV virus lysate (strain AD169) and recombinant CMV Ag Murine anti-human IgM acridinium-labeled conjugate NA NA NA
HIV Ag/Ab* <1.00 ≥1.00 S/CO CMIA HIV-1/HIV-2 Ag (recombinant) and HIV p24 Ab (mouse, monoclonal) Acridinium-labeled HIV-1 Ag (recombinant), HIV-1/HIV-2 synthetic peptides, and HIV p24 Ab (mouse, monoclonal) conjugate 322 13 True R (12); false R (1)
HAV IgM* <0.80 0.80–1.20 >1.20 S/CO CMIA HAV (human) Anti-human IgM (mouse, monoclonal) acridinium-labeled conjugate 83 0 0
HBc IgM <1.00 ≥1.00 COI ECLIA HBcAg labeled with a ruthenium complex and streptavidin-coated microparticles Biotinylated anti-human IgM (mouse, monoclonal) 131 0 0
Anti-HCV* <1.00 ≥1.00 S/CO CMIA Recombinant HCV Ags (HCr43 and c100-3) Murine anti-human IgM/IgG acridinium-labeled conjugate 104 3 True R (3)

Abbreviations: Ab, antibody; NR, nonreactive; GZ, gray zone; R, reactive; Ag, antigen; Toxo, Toxoplasma gondii; CMIA, chemiluminescent microparticle immunoassay; IgM, immunoglobulin M; ANA, antinuclear antibodies; HPV, human papillomavirus; NA, not available; CMV, cytomegalovirus; HIV, human immunodeficiency virus; S/CO, signal-to-noise ratio; HAV, hepatitis A virus; HBc, hepatitis B core; COI, cutoff index; ECLIA, electrochemiluminescence assay; HBcAg, hepatitis B core antigen; HCV, hepatitis C virus; IgG, immunoglobulin G.

The instruments used were from the following companies: *Abbott GmbH (Wiesbaden, Germany), Abbott Ireland Diagnostics Ltd. (Sligo, Ireland), and Roche Diagnostics GmbH (Manheim, Germany).

Lab Med Qual Assur 2022;44:40~47
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