Table 1

 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.

ParametersSensitivity (%)Specificity (%)Likelihood ratioPost-test probability of having the disease (%)Number of patients to be seen to make a diagnosis of axial SpACost for the testEase of inter-pretationOverall 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 pain75753147LowGood++
Response to NSAID75855215LowGood+
Uveitis15987.3284 to 3LowGood0
Family history25966.4254LowModerate0
Peripheral arthritis40904174 to 5LowModerate0
Laboratory parameters
HLA-B2790909323ModerateVery good+++
Imaging parameters
MRI (sacroiliitis)90909323HighModerate+
x Rays (sacroiliitis)8080417.45ModerateModerate+