Clinical tests on impairment level related to low back pain: A study of test reliability

The objectives of the study were, in a working population, to standardize and evaluate a set of clinical tests on impairment level related to the low back with reference to intra- and inter-rater reliability. The study was undertaken in two steps. In step 1, 15 tests were examined for inter-rater reliability by three pairs of physiotherapists and for intra-rater reliability by one physiotherapist. Intra-rater reliability was acceptable (kappa > 0.40) for 14 of the 15 tests. Inter-rater reliability was acceptable for 7 of the 15 tests. In step 2, the tests, indicating a non-acceptable inter-rater reliability (kappa less than or equal to 0.40) were further standardized and re-tested by two of the physiotherapists. This further standardization procedure resulted in an acceptable interrater reliability for all of these tests. Clinical tests of a working population should preferably be performed by the same rater. However, when tests are performed by different raters, it is suggested that test procedures should be regularly standardized, and in pain provocation tests, the magnitude of the applied pressure should be checked regularly and compared with co-raters, in order to improve inter-rater reliability.