What are the key indications for referring a patient for nerve conduction studies (NCS) and electromyography (EMG) in primary care?

Key indications for referring a patient from primary care for nerve conduction studies (NCS) and electromyography (EMG) include clinical features suggestive of peripheral nerve or neuromuscular disorders that require further diagnostic clarification. These indications encompass:

• Persistent or progressive limb weakness, especially if slowly progressive over weeks to months, warranting assessment for neuromuscular disorders such as motor neurone disease; urgent referral is indicated if there is evidence of swallowing impairment or respiratory compromise ¹.
• Symptoms of peripheral neuropathy such as persistent distal sensory disturbances (numbness, tingling, or altered sensation) with depressed deep tendon reflexes, after excluding common causes like vitamin B12 deficiency, thyroid dysfunction, diabetes, or alcohol misuse, should prompt referral for neurological assessment including NCS/EMG ¹.
• Severe or persistent carpal tunnel syndrome symptoms unresponsive to initial management, where NCS can confirm diagnosis and severity to guide treatment ¹.
• Rapidly progressive symmetrical limb weakness or numbness developing within hours to days, which may indicate acute polyneuropathies such as Guillain–Barré syndrome, requiring urgent neurological assessment and electrophysiological studies ¹.
• Focal dystonia or task-specific motor dysfunction (e.g., writer’s cramp) where EMG can assist in diagnosis and guide botulinum toxin treatment ¹.
• Sudden-onset limb weakness or sensory symptoms where stroke or central causes are excluded, and peripheral nerve involvement is suspected, NCS/EMG can help localize and characterize the lesion ¹.

In summary, NCS and EMG are primarily indicated in primary care when clinical features suggest peripheral nerve or neuromuscular pathology that cannot be diagnosed by clinical examination alone, or when confirmation and severity grading are needed to guide management or specialist referral ¹. The literature supports these indications, emphasizing the role of NCS/EMG in differentiating neuropathic from myopathic processes and in localizing lesions along the peripheral nervous system (Weber, 1990).