A telephonic single breath count test for screening of exacerbations of myasthenia gravis: A pilot study

Background Patients with myasthenia gravis (MG) may experience worsening symptoms outside of a clinical setting. A method of diagnosing and triaging such individuals would be valuable. This study gauged the viability of a nurse-administered single breath count test (SBCT) over the telephone for assessing MG exacerbations. Methods This was a retrospective, single-center review of a pilot study of 45 telephone calls from patients with MG who had worsening baseline symptoms. SBCTs were administered over the telephone to patients by trained nurses. Patients with a breath count of 25 or less were sent to the emergency department. Results Using a cutoff count of 25, the nurse-administered telephonic SBCT had a positive predictive value of 71%, sensitivity of 80%, and specificity of 60% in diagnosing an MG exacerbation. Conclusions SBCT administered by trained nurses by means of telephone may be a useful screening tool for assessing decreased respiratory function in patients with MG.