Ankylosing Spondylitis Differential Diagnosis - Medical Algorithm

Calin et al developed a short set of screening questions that can help separate spondylitis from back pain due to other causes.

Questions:

(1) onset of back discomfort before the age of 40 years

(2) insidious onset

(3) persistence for at least 3 months

(4) associated with morning stiffness

(5) improved with exercise

Question	Response	Points
onset of back discomfort	>= 40	0
	< 40	1
onset	insidious	1
	not insidious	0
persistence of back discomfort	< 3 months	0
	>= 3 months	1
associated with morning stiffness	no	0
	yes	1
response to exercise	improves	1
	no improvement	0

screening score =

= SUM(findings present)

Interpretation:

• minimum score: 0

• maximum score: 5

• A score >= 4 indicates inflammatory back pain (spondylitis) is present.

Performance:

• According to Gran, the sensitivity of the criteria is 23% and specificity 75%.

To read more or access our algorithms and calculators, please log in or register.

Screening Questionnaire for Ankylosing Spondylitis