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Point-of-Care Guides

Carpal Tunnel Syndrome

Christopher A. Alvarez, MD,
Steven R. Brown, MD, FAAFP,
University of Arizona College of Medicine, Phoenix, Arizona

American Family Physician. 2024;109(6):571-572.

Author disclosure: No relevant financial relationships.

Clinical Question

How is carpal tunnel syndrome (CTS) diagnosed clinically and how can the history and physical examination inform evidence-based management?

Evidence Summary

CTS is the most common entrapment neuropathy seen in primary care. It is caused by compression of the median nerve in the space underneath the wrist flexor retinaculum, which can produce pain in the wrist or lateral digits and thumb, paresthesia, and, in severe cases, sensory loss and weakness or atrophy of thenar muscles.

History and physical examination elements, including provocative tests, have limited accuracy compared with electrodiagnostic testing for the diagnosis of CTS. The Phalen sign has a positive likelihood ratio (LR+) of 1.4 and a negative likelihood ratio (LR−) of 0.7, and the Tinel sign has an LR+ of 1.3 and LR− of 0.8.1,2 Hypalgesia in the median nerve distribution is minimally to moderately useful for ruling in CTS, with an LR+ of 3.1, and weak thumb abduction has an LR+ of 1.8.1 A systematic review concluded that the Katz hand sensory symptom diagrams may be useful.1 According to an evidence-based guideline from the American Academy of Orthopaedic Surgery, there is strong evidence that no test alone can diagnose CTS, but the presence of thenar atrophy is useful for ruling in CTS.3 The majority of studies that examined sensitivity and specificity of history and physical examination findings for CTS were performed in specialty settings, limiting the usefulness of these findings in primary care. However, one study found that 81% of patients referred by family physicians for clinically suspected CTS had the diagnosis confirmed by a neurologist.4

The CTS-6, a validated risk score, is useful for making the diagnosis and assessing severity of CTS.5 The CTS-6 assigns points for six signs and symptoms (Table 16,7 ). Although there is no consensus on a diagnostic reference standard for CTS, a 2014 study found that compared with electrodiagnostic testing, a CTS-6 score of 12 or more had a sensitivity of 89%, a specificity of 80%, an LR+ of 4.5, and an LR− of 0.14.6 A CTS-6 score of 18 or more is 99% specific for CTS, but is only 31% sensitive (LR+ = 31, LR− = 0.70).7

TABLE 1. CTS-6 Risk Score for Diagnosing Carpal Tunnel Syndrome

Symptom or signPoints
Thenar atrophy or weakness5.0
Positive Phalen test5.0
Loss of 2-point discrimination4.5
Nocturnal numbness4.0
Positive Tinel sign4.0
Numbness predominantly or exclusively in median nerve distribution3.5
Total (range 0 to 26)_____

Note: For a cutoff of ≥ 12 points, the LR+ is 4.5 and the LR− is 0.14. If pretest probability is 50%, positive predictive value is 82% and negative predictive value is 12%. For a cutoff of ≥ 18 points, the LR+ is 31 and the LR− is 0.70. If pretest probability is 50%, positive predictive value is 97% and negative predictive value is 41%.

LR+ = positive likelihood ratio; LR− = negative likelihood ratio.

Information from references 6 and 7.

Address correspondence to Steven R. Brown, MD, FAAFP, at steven.brown@bannerhealth.com. Reprints are not available from the authors.

Author disclosure: No relevant financial relationships.

  1. 1.D'Arcy CA, McGee S. The rational clinical examination. Does this patient have carpal tunnel syndrome [published correction appears in JAMA. 2000; 284(11): 1384]?. JAMA. 2000;283(23):3110-3117.
  2. 2.Dabbagh A, MacDermid JC, Yong J, et al. Diagnostic test accuracy of provocative maneuvers for the diagnosis of carpal tunnel syndrome: a systematic review and meta-analysis. Phys Ther. 2023;103(6):pzad029.
  3. 3.Graham B, Peljovich AE, Afra R, et al. The American Academy of Orthopaedic Surgeons evidence-based clinical practice guideline on: management of carpal tunnel syndrome. J Bone Joint Surg Am. 2016;98(20):1750-1754.
  4. 4.Claes F, Bernsen H, Meulstee J, et al. Carpal tunnel syndrome diagnosed by general practitioners: an observational study. Neurol Sci. 2012;33(5):1079-1081.
  5. 5.Graham B, Regehr G, Naglie G, et al. Development and validation of diagnostic criteria for carpal tunnel syndrome. J Hand Surg Am. 2006;31(6):919-924.
  6. 6.Fowler JR, Munsch M, Tosti R, et al. Comparison of ultrasound and electrodiagnostic testing for diagnosis of carpal tunnel syndrome: study using a validated clinical tool as the reference standard. J Bone Joint Surg Am. 2014;96(17):e148.
  7. 7.Wang WL, Buterbaugh K, Kadow TR, et al. A prospective comparison of diagnostic tools for the diagnosis of carpal tunnel syndrome. J Hand Surg Am. 2018;43(9):833-836.e2.
  8. 8.Shi Q, Bobos P, Lalone EA, et al. Comparison of the short-term and long-term effects of surgery and nonsurgical intervention in treating carpal tunnel syndrome: a systematic review and meta-analysis. Hand (N Y). 2020;15(1):13-22.
  9. 9.Karjalainen TV, Lusa V, Page MJ, et al. Splinting for carpal tunnel syndrome. Cochrane Database Syst Rev. 2023(2):CD010003.
  10. 10.Ashworth NL, Bland JDP, Chapman KM, et al. Local corticosteroid injection versus placebo for carpal tunnel syndrome. Cochrane Database Syst Rev. 2023(2):CD015148.
  11. 11.Yang A, Cavanaugh P, Beredjiklian PK, et al. Correlation of carpal tunnel syndrome 6 score and physical exam maneuvers with electrodiagnostic test severity in carpal tunnel syndrome: a blinded prospective cohort study. J Hand Surg Am. 2023;48(4):335-339.
  12. 12.Bowman A, Rudolfer S, Weller P, et al. A prognostic model for the patient-reported outcome of surgical treatment of carpal tunnel syndrome. Muscle Nerve. 2018;58(6):784-789.

This guide is one in a series that offers evidence-based tools to assist family physicians in improving their decision-making at the point of care.

This series is coordinated by Mark H. Ebell, MD, MS, deputy editor for evidence-based medicine.

A collection of Point-of-Care Guides published in AFP is available at https://www.aafp.org/afp/poc.

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