TABLE 3.
POSITIVE AND NEGATIVE PREDICTIVE VALUES AND LIKELIHOOD RATIOS FOR SELECTED CELL SURFACE MARKERS IDENTIFIED BY FLOW CYTOMETRY IN UVEITIS AND B-CELL LYMPHOMA
| CELL SURFACE MARKER POSITIVE AND NEGATIVE CUT-OFF VALUES | B-CELL LYMPHOMA NUMBER OF TESTS | UVEITIS NUMBER OF TESTS | SENSITIVITY*† | SPECIFICITY*‡ | POSITIVE PREDICATIVE VALUE§ | NEGATIVE PREDICTIVE VALUE¶ | POSITIVE LIKELIHOOD RATIO# |
|---|---|---|---|---|---|---|---|
| T-cell markers | |||||||
| Uveitis vs B-cell lymphoma | |||||||
| CD2** | 0.60 | 0.71 | 0.68 | 0.63 | 2.0 | ||
| >22.8 | 10 | 21 | |||||
| ≤22.8 | 24 | 14 | |||||
| CD3 | 0.56 | 0.45 | 0.72 | 0.55 | 1.0 | ||
| >22 | 7 | 18 | |||||
| ≤22 | 17 | 14 | |||||
| CD4 | 0.60 | 0.60 | 0.62 | 0.60 | 1.5 | ||
| >10 | 13 | 21 | |||||
| ≤10 | 21 | 14 | |||||
| CD5** | 0.63 | 0.65 | 0.65 | 0.63 | 1.8 | ||
| >17 | 12 | 22 | |||||
| ≤17 | 22 | 13 | |||||
| CD7** | 0.48 | 0.73 | 0.70 | 0.53 | 1.8 | ||
| >16.6 | 7 | 16 | |||||
| ≤16.6 | 19 | 17 | |||||
| CD8 | 0.46 | 0.58 | 0.53 | 0.50 | 1.1 | ||
| >5.5 | 14 | 16 | |||||
| ≤5.5 | 19 | 19 | |||||
| CD4:CD8 ratio** | 0.60 | 0.66 | 0.64 | 0.61 | 1.7 | ||
| >1.8 | 10 | 18 | |||||
| ≤1.8 | 19 | 12 | |||||
| B-cell markers | |||||||
| B-cell lymphoma vs uveitis | |||||||
| CD20** | 0.79 | 0.77 | 0.77 | 0.79 | 3.5 | ||
| >3 | 27 | 8 | |||||
| ≤3 | 7 | 27 | |||||
| CD22** | 0.77 | 0.76 | 0.73 | 0.76 | 3.2 | ||
| >6.1 | 27 | 10 | |||||
| ≤6.1 | 8 | 25 | |||||
A test was considered positive if a larger percentage of cells bore the marker of interest than the median percentage for the entire study group and negative if it was lower than this value.
Sensitivity was defined as the number of positive tests in the reference group divided by the number of positive and negative tests in that group.
Specificity was defined as the number of negative tests in the comparison group divided by the number of negative and positive tests in that group.
Positive predictive value was defined as the number of positive tests in the reference group divided by the number of positive tests in reference and comparison groups. Values greater than 60% are considered clinically useful.
Negative predictive value was defined as the number of negative tests in the comparison group divided by the number of positive tests in the comparison and reference groups. Values greater than 90% are considered clinically useful.
Likelihood ratio was defined as the sensitivity of the factor divided by 1 – the specificity. Values equal to 1 are equivalent to coin tosses. Values greater than 1.5 or less than 0.67 are considered clinically useful.
Test names in bold indicate that quality measures were met. See text.