Table 1

Cutoff values recommended by the manufacturer for each of the three avidity assays compared in this studya

Toxo IgG avidity assayCutoff value or index for the following assay interpretation:
Low avidityGray zoneHigh avidity
Elecsys (Roche Diagnostics)<70%70% ≤ value <80%≥80%
Architect (Abbott Laboratories)<50.0%50.0% ≤ value <60.0%≥60.0%
Vidas (bioMérieux)<0.2000.200 ≤ index <0.300≥0.300
  • a For all three assays, a high avidity value allows exclusion of a primary infection within the previous 4 months.