Clinical laboratory test utilization of CSF oligoclonal bands and IgG index in a tertiary pediatric hospital

Background

Criteria developed for the diagnosis of multiple sclerosis (MS) in adults are also used in the pediatric setting. However, differential diagnosis in pediatric-onset MS (POMS) is distinct from that of adult-onset MS. There is little literature characterizing the utility of oligoclonal bands (OCB) and IgG index in differentiating POMS from other childhood diseases with overlapping clinical presentation which can require immediate treatment.

Methods

A retrospective review of all MS panels resulted between March 2022 and May 2023 on patients age ≤ 18 years at one tertiary care pediatric hospital in the northeastern United States was performed with pediatric neurology collaboration to characterize clinical utility (n = 85 cases).

Results

Demyelinating diseases accounted for 31 of 85 total cases (36.5%), 12 of these cases were POMS (14%). Other diagnoses consisted of psychiatric etiologies (17.6%), infectious meningitis/encephalitis (5.9%), and migraine (5.9%). Elevated IgG index was seen in 67% of those with demyelinating diseases, versus only 13% of those with other conditions. Unique OCBs were found in 41% of those with demyelinating diseases, versus only 9% of those with other conditions. Fourteen of 15 patients (93.3%) with psychiatric conditions had normal MS panels.

Conclusions

Patients with demyelinating diseases were more likely to have elevated IgG index and unique OCBs versus patients with other conditions. For pediatric hospitals without in-house OCB evaluation, implementation of an in-house IgG index may serve as a rapid screen for differentials that include demyelinating diseases while awaiting OCB results, in the appropriate clinical context.

Impact statement

IgG index and CSF oligoclonal bands are important tools in the diagnosis of patients with suspected Multiple Sclerosis (MS). In the pediatric population, these markers are used to differentiate pediatric-onset MS (POMS) from other neurologic, psychiatric, and inflammatory diseases that display clinical overlap. The use of these markers in differentiating these conditions has not been thoroughly investigated. We examined the associations between abnormal markers and final diagnoses in pediatric patients undergoing testing for POMS in order to identify trends that may enhance ordering and reporting practices.