TABLE 2.
Serum IgG assay qualification parameters
| Parameter | Antigen | |||||
|---|---|---|---|---|---|---|
| PT | PRN | FHA | FIM 2/3 | DT | TT | |
| Specificity (%)a | ||||||
| PT | 88.4 | 0.0 | 0.0 | 0.0 | 8.8 | 0.0 |
| PRN | 11.1 | 98.1 | 0.6 | 16.1 | 8.6 | 1.9 |
| FHA | 8.0 | 0.0 | 95.2 | 0.0 | 8.4 | 0.0 |
| FIM 2/3 | 0.0 | 4.7 | 0.0 | 98.9 | 0.0 | 0.0 |
| DT | 9.4 | 5.0 | 6.7 | 5.7 | 99.0 | 4.6 |
| TT | 0.0 | 0.0 | 0.0 | 0.0 | 9.3 | 99.3 |
| Relative accuracy and precision | ||||||
| Mean bias (%RE) | −9.9 | −3.7 | 3.2 | −6.7 | −8.3 | −4.8 |
| Repeatability (%CV) | 8.6 | 4.9 | 9.3 | 7.4 | 5.8 | 9.6 |
| Intermediate precision (%CV) | 13.2 | 11.1 | 14.4 | 11.6 | 11.7 | 12.0 |
| Limits of detection | 0.001 | 0.0007 | 0.002 | 0.006 | 0.00001 | 0.00003 |
| In-house standard (mean) | ||||||
| Limits of quantitation (IU/mL) | ||||||
| LLOQ (IU/mL) | 1.00 | 0.70 | 2.00 | 6.00 | 0.01 | 0.04 |
| Mean bias (%RE) | −14.3 | −16.1 | −15.2 | −15.5 | −9.2 | −11.7 |
| Repeatability (%CV) | 10.2 | 6.20 | 7.78 | 7.20 | 12.20 | 9.56 |
| Intermediate precision (%CV) | 9.56 | 6.01 | 7.21 | 7.08 | 11.64 | 9.56 |
| Linearity and dilutability | ||||||
| Coefficient of determination | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 0.98–1.0 |
| Regression line slope | 1.04–1.07 | 0.96–0.99 | 0.97–1.00 | 0.94–1.01 | 0.91–1.00 | 0.85–0.973 |
| Matrix effect | ||||||
| Serum/plasma ratio | 1.03 | 0.96 | 0.90 | 0.91 | 1.00 | 0.89 |
| 95% CI | 0.99–1.07 | 0.91–1.02 | 0.79–1.01 | 0.81–1.01 | 0.97–1.03 | 0.79–0.99 |
| Robustness | ||||||
| 75 min (IU/mL)b | 61.4 | 63.9 | 232.4 | 326.4 | 0.6 | 3.8 |
| 60 min (IU/mL)c | 60.0 | 60.7 | 254.8 | 313.9 | 0.5 | 3.6 |
| P value | 0.38 | 0.09 | 0.18 | 0.49 | 0.06 | 0.59 |
| Concentration | ||||||
| Mean of ratios b/c | 1.027 | 1.043 | 0.893 | 1.058 | 1.043 | 0.992 |
| SE | 0.017 | 0.04 | 0.033 | 0.036 | 0.012 | 0.047 |
a
Bolded numbers represent % inhibition with matching assay antigen.
b
Antibody titers from assay using 75 min incubation.
c
Antibody titers from assay using 60 min incubation.