Frequency of the circular fluorescent pattern (“2”) in different patient populations (serum dilution 1/40). Sensitivity and specificity of the immunofluorescence assay
| Negative pattern (0 or 1) | Positive pattern (2) | Cohort | |
|---|---|---|---|
| Sensitivity1-150 | |||
| SLE | 27 (33)‡ | 53 (66) | 80 |
| Sjögren’s syndrome | 33 (97) | 1 (3) | 34 |
| Ankylosing spondylarthritis | 38 (100) | 0 (0) | 38 |
| Rheumatoid arthritis | 15 (100) | 0 (0) | 15 |
| Osteopenia | 17 (100) | 0 (0) | 17 |
| Healthy controls | 224 (100) | 0 (0) | 224 |
| Specificity† versus | |||
| Healthy controls | 224 (100) | ||
| Osteopenia | 17 (100) |
↵1-150 Sensitivity is defined as the ratio of diseased patients correctly classified by the assay, divided by the total number of diseased patients, expressed as a percentage. †Specificity is defined as the ratio of non-diseased patients correctly classified by the assay, divided by the total number of non-diseased patients, expressed as a percentage. ‡Number (percentage). Fluorescence pattern scores: 0 = no significant picture; 1 = disseminated points on the membrane; 2 = continuous ring around the cells.