Electromyography, nerve conduction studies and muscle biopsy
When to order nerve conduction studies, needle EMG, repetitive stimulation and muscle biopsy, how to read a report step by step with typical values and worked examples, the yield and blind spots of each test, and the results that change treatment.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- NCS measure large myelinated fibres: amplitude counts axons, latency and velocity measure myelin. Needle EMG looks at the muscle: denervation, reinnervation or myopathy. RNS and single-fibre EMG test the neuromuscular junction.
- They extend the examination. Order with a written question ("ulnar neuropathy at the elbow or C8 radiculopathy?") and they answer it well. Order "?neuropathy" and you get a description.
- Muscle biopsy is now a later step. Myositis antibodies, MRI and genetic tests answer many questions first.
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Sources
- Therapeutic Guidelines: NeurologyAU/NZTherapeutic Guidelines Limited, current online version, accessed November 2026
- Proper performance and interpretation of electrodiagnostic studies (AANEM position statement). Muscle Nerve 2020;61:567-9American Association of Neuromuscular and Electrodiagnostic Medicine, 2020
- Potential risks of iatrogenic complications of nerve conduction studies (NCS) and electromyography (EMG) (Gechev A et al. Clin Neurophysiol Pract 2016;1:62-6)Clinical Neurophysiology Practice, 2016
- Electrodiagnostic reference values for upper and lower limb nerve conduction studies in adult populations (Chen S et al. Muscle Nerve 2016;54:371-7)AANEM Normative Data Task Force (Muscle and Nerve), 2016
- A neurophysiological grading scale for carpal tunnel syndrome (Bland JD. Muscle Nerve 2000;23:1280-3)Muscle and Nerve, 2000
- European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of CIDP: second revision (Van den Bergh PYK et al. Eur J Neurol 2021;28:3556-83)European Journal of Neurology, 2021 (current November 2026)
- The diagnostic accuracy of the second revision of the EAN/PNS guideline for diagnosing CIDP (van Doorn IN et al. Eur J Neurol 2026;33:e70726)European Journal of Neurology, 2026
- 224th ENMC International Workshop: clinico-sero-pathological classification of immune-mediated necrotizing myopathies (Allenbach Y et al. Neuromuscul Disord 2018;28:87-99)European Neuromuscular Centre (Neuromuscular Disorders), 2018
- 239th ENMC International Workshop: classification of dermatomyositis (Mammen AL et al. Neuromuscul Disord 2020;30:70-92)European Neuromuscular Centre (Neuromuscular Disorders), 2020
- 272nd ENMC international workshop: revision of the ENMC 2013 diagnostic criteria for inclusion body myositis (Lilleker JB et al. Neuromuscul Disord 2024;37:36-51)European Neuromuscular Centre (Neuromuscular Disorders), 2024
- 2017 EULAR/ACR classification criteria for adult and juvenile idiopathic inflammatory myopathies (Lundberg IE et al. Ann Rheum Dis 2017;76:1955-64)Annals of the Rheumatic Diseases, 2017 (still current November 2026; revision in development)
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy