Table 1.
System | Assay (unit)a | Negative/low | Gray zone | Positive/high |
---|---|---|---|---|
Vidas | IgG (IU/ml) | <4.0 | 4.0 ≤ x < 8.0 | ≥8.0 |
IgM (index) | <0.55 | 0.55 ≤ x < 0.65 | ≥0.65 | |
IgG avidity (index) | <0. 2 | 0.2 ≤ x < 0.3 | ≥0.3 | |
Architect | IgG (IU/ml) | <1.6 | 1.6 ≤ x < 3.0 | ≥3.0 |
IgM (index) | <0.50 | 0.50 ≤ x < 0.60 | ≥0.60 | |
IgG avidity (%) | <50.0 | 50.0 ≤ x < 60.0 | ≥60.0 | |
Liaison | IgG (UI/ml) | <7.2 | 7.2 ≤ x < 8.8 | ≥8.8 |
IgM (AU/ml) | <6.0 | 6.0 ≤ x < 8.0 | ≥8.0 | |
IgG avidity (index) | <0.30 | 0.30 ≤ x < 0.40 | ≥0.40 |
For all three IgG avidity assays, a high avidity value allows exclusion of a primary infection dating back less than 4 months. IU, international unit; AU, arbitrary unit.