Purpose
To clarify the sensitivity, specificity, and interrater reliability of the scratch
collapse test for carpal tunnel syndrome (CTS) and cubital tunnel syndrome, using
blinded observers in a general patient population.
Methods
Ninety-two subjects were recruited from all patients referred for electrodiagnostic
studies for upper extremity symptoms that were thought to be related to an entrapment
mononeuropathy. The scratch collapse test was performed twice on each patient, once
by the resident and once by a nerve conduction technician. Both observers were blinded
to all aspects of the patient’s presentation. Sensitivity and specificity for the
scratch collapse test were calculated twice, once using electrodiagnostic testing
results and a second time using a validated clinical tool (the CTS-6) as the reference
standard. The interrater reliability was also calculated.
Results
Using electrodiagnostic criteria as a reference standard, the scratch collapse test
had a sensitivity of 7% and a specificity of 78% for CTS. Using clinical criteria
as a reference standard, the test had a sensitivity of 15% and a specificity of 87%.
For cubital tunnel syndrome, the sensitivity was 10% and the specificity was 90%.
For the resident/technician 1, kappa was –0.025 (worse than chance alone). For the
resident/technician 2, kappa was 0.211 (fair strength of agreement).
Conclusions
The sensitivity of the scratch collapse test for CTS and cubital tunnel syndrome was
lower than that found in other studies, regardless of whether a clinical or an electrodiagnostic
reference standard was used. The specificity was high. Overall interrater agreement
was lower than previously reported. These results call into question the sensitivity
and interrater reliability of the scratch collapse test for CTS and cubital tunnel
syndrome.
Type of study/level of evidence
Diagnostic II.
Key words
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References
- Scratch collapse test for evaluation of carpal and cubital tunnel syndrome.J Hand Surg Am. 2008; 33: 1518-1524
- Signs of neuropathic pain depend on signals from injured nerve fibers in a rat model.Brain Res. 1993; 610: 62-68
- Silent period induced by cutaneous stimulation.Electroencephalogr Clin Neurophysiol. 1991; 81: 344-352
- Evaluation of the scratch collapse test in peroneal nerve compression.Plast Reconstr Surg. 2011; 128: 933-999
- Evaluation of the scratch collapse test for the diagnosis of carpal tunnel syndrome.J Hand Surg Eur Vol. 2014; 39: 181-186
- Diagnosis of carpal tunnel syndrome: interobserver reliability of the blinded scratch-collapse test.J Hand Microsurg. 2014; 6: 5-7
- The accuracy of the scratch collapse test performed by blinded examiners on patients with suspected carpal tunnel syndrome assessed by electrodiagnostic studies.J Hand Surg Am. 2017; 42: 386.e1-386.e5
- Effects of bias on the results of diagnostic studies of carpal tunnel syndrome.J Hand Surg Am. 2009; 34: 1006-1013
- Development and validation of diagnostic criteria for carpal tunnel syndrome.J Hand Surg Am. 2006; 31: 919-924
- Diagnosis and Treatment of Carpal Tunnel Syndrome.(Available at:)http://www.orthoguidelines.org/topic?id=1020Date accessed: June 4, 2017
- The value added by electrodiagnostic testing in the diagnosis of carpal tunnel syndrome.J Bone Joint Surg Am. 2008; 90: 2587-2593
- Electrodiagnostic evaluation of carpal tunnel syndrome.Muscle Nerve. 2011; 44: 597-607
- Practice parameter for electrodiagnostic studies in carpal tunnel syndrome: summary statement.Muscle Nerve. 2002; 25: 918-922
- Practice parameter for electrodiagnostic studies in ulnar neuropathy at the elbow: summary statement.Muscle Nerve. 1999; 22: 408-411
- A comparison of three diagnostic tests for carpal tunnel syndrome using latent class analysis.J Bone Joint Surg Am. 2015; 97: 1958-1961
- Important details in performing and interpreting the scratch collapse test.Plast Reconstr Surg. 2018; 141: 399-407
Article info
Publication history
Published online: April 13, 2020
Accepted:
February 21,
2020
Received:
May 4,
2019
Footnotes
No benefits in any form have been received or will be received related directly or indirectly to the subject of this article.
Identification
Copyright
© 2020 by the American Society for Surgery of the Hand. All rights reserved.
