Characteristics of commercially available CMV-specific cell-mediated immunity assays
| QuantiFERON-CMV | T-SPOT.CMV | T-Track CMV | CMV T cell immunity panel | |
|---|---|---|---|---|
| Assay principle | ELISA | ELISpot | ELISpot | Intracellular staining and flow cytometry |
| Product company | Qiagen | Oxford Immunotec | Lophius Bioscience | Viracor Eurofins |
| Sample | 3 mL of whole blood | Purified PBMCs from 12 mL of whole blood | Purified PBMCs from 15 mL of whole blood | 10 mL of whole blood |
| PBMCs required | No | Yes | Yes | Yes |
| CMV antigen | Various HLA class I restricted 21 CMV peptides | pp65, IE-1 | T-activated CMV-specific pp65 and IE-1 | Whole viral lysate, pp65, IE-1 |
| Measurement | IFN-γ | IFN-γ–specific spot-forming cells | IFN-γ–specific spot-forming cells | % CMV-specific CD4+ and CD8+ T-cells |
| Cut off for positivity | CMV antigen minus Nil control ≥0.2 | NA | Either pp65 or IE-1 ≥10 spots |
CMV-specific CD4+ or CD8+ responses >0.2% |
| Measuring range (linearity) | Up to 10 IU/mL | NA | 10–1,000 spots | NA |
| Clinical sensitivity | 80.5% (insert) | 93.3% (insert) | 89.6% (insert) | 79%–82% [66] |
| Time to test | 16–24 hours | 30–40 hours | 30–40 hours | 3–4 business days from receipt of specimen in USA |
| Quality control | Nil control ≤8.0 Mitogen control |
Nil control <10 spots Positive control (mitogen solution containing PHA) >20 spots |
Negative control <10 spots Positive control (SEB) >400 spots |
Negative control Positive control (SEB) |
| Comment | CE-marked Not FDA-approved |
CE-marked Not FDA-approved |
CE-marked Not FDA-approved |
Not FDA-approved |
CMV, cytomegalovirus; ELISA, enzyme-linked immunosorbent assay; ELISpot, enzyme-linked immunosorbent spot; PBMC, peripheral blood mononuclear cell; HLA, human leukocyte antigen; IFN-γ, interferon-gamma; NA, not available; PHA, phytohemagglutinin; SEB,