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Background Single fibre electromyography (SFEMG) is a sensitive tool for diagnosing myasthenia gravis (MG), but its specificity can vary. This audit evaluates its diagnostic yield in patients referred for suspected MG.Methods Over a course of two years, we reviewed 49 consequitive patients who were referred for SFEMG due to clinical suspicion of MG. SFEMG was performed on the Frontalis, Obicularis Oculi or the Extensor digitorium communis, and results were correlated with presenting symptoms and signs, antibody status and final clinical diagnosis.Results Of 49 patients, 16 (32.7%) had abnormal SFEMG results. Among these, 8 were diagnosed with MG, 6 did not have MG, and 2 had unknown diagnoses. The positive predictive value (PPV) of SFEMG ranged from 50% (assuming unknown cases as false positives) to 57.1% (excluding unknown cases). In our cohort other than a diagnosis of MG, patients with any physical signs had the highest odds (3.30) of having a positive SFEMG.Conclusion SFEMG demonstrated moderate diagnostic yield in this cohort, with a PPV of 50–57.1%. False positives highlight the need for clinical correlation.The reduced PPV of SFEMG in this cohort (50–57.1%) may reflect referral bias. Additionally, the inclusion of patients with other neuromuscular conditions or non-specific symptoms further lowers the prevalence of true MG in this population, reducing PPV. These findings highlight the importance of interpreting SFEMG results in the context of clinical findings and antibody status to improve diagnostic accuracy.