Background: Beta(2)-transferrin (beta-2 trf) is a desialated isoform of transferrin found only in cerebrospinal fluid (CSF), ocular fluids, and perilymph. In aural, nasal, and wound drainages, this protein is an important marker of CSF leakage. Immunofixation electrophoresis (IFE) on agarose gels is a widely accepted qualitative technique for detection of small amounts of beta-2 trf, but disadvantages include lengthy transfer immunoblotting techniques or the requirement of at least 2 mL of sample.
Methods: Using eight applications of unconcentrated sample on high-resolution agarose gels with an automated electrophoresis system (Helena SPIFE 3000), we developed a rapid method for beta-2 trf. Evaluation studies included reproducibility of migration distance (mm), limit of detection, specificity, and concordance of results compared with those reported by a reference laboratory. Neuraminidase-treated serum was the source of beta-2 trf for our sensitivity and specificity studies. Transferrin was measured by rate nephelometry.
Results: The 2.5-h procedure demonstrated reproducible migration (CV <2.5%) on five lots of gels. Detection of beta-2 trf at 0.002 g/L in an unconcentrated sample was attributed to reproducible application, quality of the anti-trf antiserum, and a sensitive acid violet stain. Our beta-2 trf findings (two negative and five positive) in seven available clinical samples agreed with the reference laboratory results. In 12 months after its inception, this test was ordered 48 times vs 13 in the previous year when testing was sent out.
Conclusion: This method provides physicians with a rapid, reliable aid in the diagnosis of suspected CSF leakage, as described in a case report.