To evaluate the diagnostic value of cerebrospinal fluid oligoclonal bands (OCBs) in children (<18 years).

Cerebrospinal fluid OCBs are positive in 90–95% of adult-onset multiple sclerosis cases. However, multiple sclerosis is rare in children, and OCBs are present in only 0–10% of children with acute disseminated encephalomyelitis. Accordingly, OCBs may be of limited diagnostic value in children. 

In a nationwide population-based setting, we retrieved data on 2,055 children’s OCB examination including concordant cerebrospinal fluid biomarkers during 1994–2017. Case ascertainment was by review of medical records and diagnostic codes. We used Fisher’s exact test to explore distribution differences of OCB positivity in acquired demyelinating syndromes (ADS) before and after 12 years of age and calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of OCBs to distinguish ADS from the other diagnostic groups. 

Median age at OCB examination was 15.2 years (range=1.8–18.0) and 10% were OCB positive. OCB positivity was the highest in ADS (52%), but it was age-dependent: 21% in children with ADS before age 12 years and 68% in children 12–17 years (p<0.0001) due to the higher incidence of multiple sclerosis in the latter. Positive OCBs were not predictive of ADS before age 12 years compared with the other diagnostic groups. However, positive OCBs in children aged 12–17 years were highly predictive of ADS compared with CNS infections and non-ADS immune-mediated CNS diseases (PPV: 0.89; 95% CI=0.82–0.94; p<0.0001), but negative OCBs were not discriminatory (NPV: 0.35; 95% CI=0.17–0.57); p=0.17). 

In a clinical setting, cerebrospinal fluid OCB examination may be diagnostically valuable only in children aged 12–17 years if there is clinical suspicion of multiple sclerosis, and in such circumstances only a positive test has clinically relevant predictive value.