To determine the utilization of genetic testing in patients seen by a neurologist within a large private insurance population.

Clinical genetic testing is an increasingly common component of modern-day neurological practice, with a rapidly growing set of tools available for ascertaining potential causes of disease. Unfortunately, little is known about the utilization of genetic testing on a population-wide scale.

Using the Optum healthcare claims database, we identified patients who had been evaluated by a neurologist no more than 30 days prior to initial genetic testing. Within this group, we then categorized genetic testing between 2014-2016 on the basis of Current Procedural Terminology (CPT) codes related to molecular and genetic testing. We also evaluated International Classification of Disease Version 9 Clinical Code Classifications (ICD-9 CCS) associated with testing.

From 2014-2016, a total of 45,014 claims were placed for 29,951 patients who had been evaluated by a neurologist within the preceding 30 days. Of these, 29,926 (66.5%) were associated with codes that were too non-specific to infer what test was actually performed. Among those claims where the test was clearly identifiable, 7,307 (16.2%) were likely obtained for purposes of neurological diagnosis, while the remainder (17.2%) were obtained for non-neurological purposes. An additional 3,793 claims (8.4%) wherein the test ordered could not be clearly identified were associated with a neurology-related ICD-9 CCS.

Accurate assessment of genetic testing utilization using claims data is not possible given the high prevalence of non-specific codes. Reducing the ambiguity surrounding CPT codes and the actual testing performed will become even more important as more genetic tests become available.