Immunofixation to quantify β2-transferrin in cerebrospinal fluid to detect leakage of cerebrospinal fluid from skull injury

Abstract

β2-Transferrin, the desialated form of transferrin normally found only in cerebrospinal fluid (CSF) and aqueous and vitreous humor, is detected by high-resolution immunofixation (IFE). It is not normally found in nasal or aural fluids, saliva, tears, or serum. Detection in nasal fluid has been suggested to document CSF leakage into the nose after skull injury. We measured β2-transferrin in 48 samples of CSF. IFE of the CSF was performed on high-resolution agarose gels and stained with Coomassie Blue, β2-Transferrin was estimated by quantifying the total transferrin by rate nephelometry and then determining the percentage of transferrin in the β2 vs β1 region by densitometric scanning of the IFE pattern. We accurately quantified as little β2-transferrin as 2.5 mg/L in the CSF samples. The β2-transferrin fraction was clearly visible by IFE at concentrations <2.5 mg/L, but accurate quantification was difficult. In the samples assayed, the range of β2-transferrin was 4.6 ± 1.9 mg/L. Use of this technique to examine rhinorrhea in a motor-vehicle-accident patient confirmed leakage of CSF into the nasal cavity through a vent in the left olfactory groove.