Test library › Low back & pelvis
Clinical tests for sacroiliac joint pain, compared
Pain arising from the sacroiliac joint, where the base of the spine (sacrum) meets the pelvis. Usually felt in the buttock, below the waist, on one side.
The 5 tests in the library for sacroiliac joint pain, side by side, each with the published accuracy figures that exist for it. Click a test for what each result means, any caution, and the source.
| Test | Sensitivity | Specificity | LR+ | LR− | Verdict |
|---|---|---|---|---|---|
| Compression test | 69% | 69% | 2.2 | 0.45 | A weak test on its own |
| Distraction test | 60% | 81% | 3.2 | 0.49 | A weak test on its own |
| Gaenslen's test | 52% | 74% | 2 | 0.65 | A weak test on its own |
| Sacral thrust test | 63% | 75% | 2.5 | 0.49 | A weak test on its own |
| Thigh thrust (P4) test | 88% | 69% | 2.8 | 0.17 | Best used to rule out |
Reading the table
A high LR+ makes a positive result useful for ruling the condition in; a low LR− makes a negative result useful for ruling it out. A test can be good in one direction and weak in the other, and the figures come from different studies and patient groups, so compare them with care.
No single test decides it; the book reads these as Laslett's provocation cluster, where a negative cluster is worth acting on and a positive one raises the question but does not settle it.
Tests for the same problem are rarely independent, so a second positive adds much less than its own figure suggests. Do not multiply their figures together. Where a combination has been tested as a cluster or a decision rule, Rule It In, Rule It Out gives that published result.
To turn a figure into a probability for your patient, use the probability calculator.
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This page gives the published figures. Rule It In, Rule It Out adds how to do each test, what counts as positive, how to read the result, and, where studied, whether combining tests helps.
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