Does specificity of electrodiagnostic test referrals predict test outcome in children?

INTRODUCTION/AIMS: Electrodiagnostic testing (EDX) is important in evaluation of pediatric neuromuscular disease. Non-specific referrals have emerged as a leading reason for EDX in recent years. We examine whether referral-specificity is predictive of test outcomes in children.

METHODS

EDX referrals and outcomes were audited over a 7-year period from 2013 to 2020 at CHI-Crumlin. Pre-test details were coded and compared to EDX outcomes using multinomial logistic regression.

RESULTS

EDX studies were performed in 702 children (median age 10.2 years). In 36% of patients, EDX-referrals did not specify any pre-test diagnosis. Mononeuropathy (24%) and polyneuropathy (15%) were the leading pre-specified diagnoses as well as the most common test outcomes. Neurology and orthopedics/plastic surgery contributed the majority of referrals. Metabolic medicine and hematology/oncology were most likely to pre-specify a working diagnosis and were the specialties with both the highest proportion of abnormal outcomes and referral accuracy. EDX abnormality was present in 42% of patients and was predicted by specificity of referral and the absence of pain as a leading symptom. The accuracy of specified pre-test diagnoses was highest for suspected anterior horn cell disorders (67%). Accuracy of referrals, as well as abnormal test outcomes, were negatively predicted by the presence of pain as a leading symptom.

DISCUSSION

EDX is informative in children but the likelihood of abnormal test-outcomes is diminished when a pre-specified working diagnosis is lacking or when the primary reason for referral is pain.