TABLE 1.
Characteristics of commercial immunoassays included in the study
| CIA | Solid-phase type | Platform | Antigen | Detection system | Standarda | Range and interpretation of results (IU/ml) |
Alternative range and interpretation of results (IU/ml)b | |
|---|---|---|---|---|---|---|---|---|
| Europe | USA | |||||||
| Architect (Abbott Diagnostics) | Microparticles | Automated | Partially purified virus | Chemiluminescence | RUB-1-94 | <5.0, negative; ≥10, positive | ||
| Cobas 6000 (Roche Diagnostics) | Magnetic microparticles | Automated | Rubella-like particles and recombinant E1 antigen | Electrochemiluminescence (ECL) | RUB-1-94 | <10, negative; ≥10, positive | <10, negative; ≥10, positive | |
| Vidas (bioMérieux) | Solid-phase receptacle | Rubella antigen (strain MR 383) | MUP (4-methyl-umbelliferyl phosphatase) | RUB S (Europe), RUB-1-94 (USA) | <10, negative; ≥15, positive | <5, negative; ≥10, positive | ||
| DxI (Beckman Coulter) | Paramagnetic beads | Automated | Rubella antigen (strain HPV77) | Chemiluminescence | RUB S | <10, negative; ≥15, positive | ||
| Centaur (Siemens Healthcare) | Paramagnetic particles | Automated | Not available | Chemiluminescence | Not available | <5.0, negative; ≥10, positive | ||
| Enzygnost (Siemens Healthcare) | Plastic wells | Microplate | Virus lysate | Tetramethylbenzidine-hydrogen peroxide | RUB S | <3, negative; >7, positive | ||
| LXL Liaison rubella IgG (DiaSorin) | Magnetic particles | Automated | Inactivated rubella viral particle (strain HPV77) | Chemiluminescence | RUBI-1-94 | <10, negative; ≥10, positive | Qualitative assay | <5.0, negative; ≥10, positive |
| Serion | Plastic wells | Inactivated rubella virus preparationn (strain HPV77) | p-Nitrophenylphosphate | RUB S | <10, negative; ≥20, positive | |||
a
RUBI-1-94, 1st NIBSC international standard (3rd WHO reference standard preparation); RUB S, 2nd WHO reference standard preparation.
b
For the DiaSorin assay, alternative cutoffs are available and the choice of the cutoff depends on the laboratory.