Clinical, laboratory, and imaging parameters which should be considered for screening of patients with chronic low back pain * for axial SpA by primary care physicians. For more details see text.
| Parameters | Sensitivity (%) | Specificity (%) | Likelihood ratio | Post-test probability of having the disease (%) | Number of patients to be seen to make a diagnosis of axial SpA | Cost for the test | Ease of inter-pretation | Overall rating |
|---|---|---|---|---|---|---|---|---|
| Overall rating whether suitable as a primary simple screening parameter: 0, not suitable (because of low sensitivity); +, moderate; ++, good; +++, very good. | ||||||||
| *Age of onset of back pain <45 years and duration >3 months. | ||||||||
| ESR, erythrocyte sedimentation rate; CRP, C reactive protein. | ||||||||
| Clinical parameters | ||||||||
| Inflammatory back pain | 75 | 75 | 3 | 14 | 7 | Low | Good | ++ |
| Response to NSAID | 75 | 85 | 5 | 21 | 5 | Low | Good | + |
| Uveitis | 15 | 98 | 7.3 | 28 | 4 to 3 | Low | Good | 0 |
| Family history | 25 | 96 | 6.4 | 25 | 4 | Low | Moderate | 0 |
| Peripheral arthritis | 40 | 90 | 4 | 17 | 4 to 5 | Low | Moderate | 0 |
| Laboratory parameters | ||||||||
| HLA-B27 | 90 | 90 | 9 | 32 | 3 | Moderate | Very good | +++ |
| ESR/CRP | 50 | 80 | 2.5 | 11.6 | 10 | Moderate | Good | 0 |
| Imaging parameters | ||||||||
| MRI (sacroiliitis) | 90 | 90 | 9 | 32 | 3 | High | Moderate | + |
| x Rays (sacroiliitis) | 80 | 80 | 4 | 17.4 | 5 | Moderate | Moderate | + |