Clinical significance of a single cerebrospinal fluid immunoglobulin band: A retrospective study

To demonstrate an inflammatory process in the central nervous system, the presence of at least two immunoglobulin (Ig) bands in the cerebrospinal fluid (CSF) is required. So far, the presence of a single abnormal Ig band is considered as negative.The objective was to assess retrospectively the significance of a single CSF Ig band in clinical practice.Out of 10,286 CSF analyses, we retained 214 results with single Ig. An inflammatory neurological disorder was diagnosed in 41% of patients.Despite a modest sensitivity, the presence of a single CSF Ig band may be a biomarker of an inflammatory mechanism and, as such, may prompt the clinician to repeat the analysis when the clinical context remains suggestive.