Introduction: Intrathecal immunoglobulins (Ig) synthesis, reflected by oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) is observed in up to 90 percent of patients with clinically definite Multiple Sclerosis (MS). The gold standard laboratory test to establish the presence of OCBs in CSF of MS patients is isoelectric focusing (IEF). However, a quicker and less expensive method has been developed: immunofixation (IF).
Methods: The aim of this study was to compare these two methods carried out 74 CSF/serum pairs of MS, 103 CSF/serum pairs of subject controls and to determine their sensitivity and specificity.
Results: The agreement between results from IEF and IF was excellent (Kappa = 0.84). IEF sensitivity (78 percent) was not significantly different from that of IF (74 percent) (p = 0.3). Similarly, the specificity of IEF (93 percent) was not significantly different from that of IF (95 percent) (p = 0.2).
Conclusion: IF is a semi automated method which is easier to perform than IEF and which appears to be as efficient as IEF.