Table 1.
Performance of commercially available immunologic tests for antibodies against Sarcocystis neurona
| Test | Laboratory | Interpretation | Reported performance | ||
|---|---|---|---|---|---|
| Sample | Sensitivity (%) | Specificity (%) | |||
| WB87 | EDS | Band pattern read and interpreted visually (subjective) | Serum | 8993, 8082, 8983 | 7193, 3882, 8783 |
|
UC Davis IDEXX |
Results usually reported as negative, weak positive, low positive, or positive | CSF | 8993, 8782 | 8993, 4482 | |
| mWB90 | Michigan State | Similar to standard WB (above) | Serum | 10090, 8983 | 9890, a, 6983 (a n.b., negative cases not from North America) |
| IFAT83 | UC Davis | Serum positive at ≥1:80 has ≥55% probabilitya of EPM | Serum | 8983, 8384, 9489, 5971 | 10083, 9784, 8589, 7171 |
| Serum negative at ≤1:40 has ≤33% probabilitya of EPM | CSF | 10084, 9289, 6571 | 9984, 9089, 9871 | ||
| CSF positive at ≥1:5 has 92% probabilitya of EPM | Serum:CSF titer ratio | 6571 | 9871 | ||
| SAG1 ELISA86 | Antech | Serum positive at ≥1:16 but recommended cutoff ≥1:32 | Serum | 6888, 1389 | 7188, 9789 |
| SAG2, 4/3 ELISA91 | EDS | Serum positive for exposure at ≥1:250 | Serum | 30–86 (depending on cutoff)72, 7171 | 37–88 (depending on cutoff)72, 5071 |
| CSF correlates well with EPM if ≥1:40 | CSF | 77–96 (depending on cutoff)72, 8871 | 58–96 (depending on cutoff)72, 8671 | ||
| Serum:CSF titer ratio very predictive of EPM if ≤100 | Serum:CSF titer ratio | 86 (cutoff ≤50) or 93 (cutoff ≤100)72, 8871 | 96 (cutoff ≤50) or 83 (cutoff ≤100)72, 10071 | ||
| SAG1, 5, 6 ELISA92 | Pathogenes | Serum positive at ≥1:8, indicating infection | Serum | N/A | N/A |
WB, Western blot; mWB, modified Western blot; IFAT, indirect fluorescent antibody test; SAG, surface antigen; ELISA, enzyme‐linked immunosorbent assay; EDS, Equine Diagnostic Solutions (Lexington, KY); UC Davis, University of California at Davis; EPM, equine protozoal myeloencephalitis; CSF, cerebrospinal fluid.
a
Based on pretest probability of 10%; see reference 85.