Detection of beta-2 transferrin in otorrhea and rhinorrhea in a routine clinical laboratory setting

Abstract

A simple, straightforward, and rapid method for the detection of beta-2 transferrin in otorrhea and rhinorrhea that can be used in a routine clinical laboratory is described. The beta-2 transferrin was detected by agarose gel electrophoresis of the fluid on Beckman Paragon equipment, followed by pressure transfer to a nitrocellulose membrane and then incubation with enzyme-labeled antitransferrin antibody and substrate. The procedure was fast (3.5 h) and sensitive (detected as little as 1 microgram/ml) and required only 3 microliters of fluid. Beta-2 transferrin was detected in cerebrospinal fluid diluted up to eightfold. No special training or expertise was needed, and all equipment and procedures used are commonly available in a routine clinical laboratory.

Diagnosis of cerebrospinal fluid rhinorrhea: an evidence‐based review with recommendations

“…Various testing methods were described in these studies, including isoelectric focusing, immunofixation, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) with immunoblotting. Regardless of the testing method used, the sensitivity ranged from 87% to 100% and the specificity from 71% to 100% …”

“…The primary objective of 4 of the identified studies was reporting the accuracy of a specific beta‐2 transferrin testing method in comparison to established methods rather than highlighting the role of beta‐2 transferrin in the diagnostic algorithm for CSF rhinorrhea . However, the CSF samples used for these studies are from the same skull‐base CSF leak patient population, so they retain their validity.…”

“…These modalities have their own limitations, however, making it difficult to know the exact accuracy of beta‐2 transferrin testing. The consistently high sensitivities and specificities in multiple studies, as well as the fact that it is noninvasive and inexpensive, support it as a very reliable and cost‐effective test for the confirmation of CSF leak (Supporting material 4) Aggregate grade of evidence: C (Level 3: 8 studies; Level 4: 1 study); Benefit: Noninvasive, highly accurate test; Harm: Delay in diagnosis due to the need to perform the test in a specialty laboratory; Cost: $37.90; Benefits‐harm assessment: Preponderance of benefit over harm; Value judgments: Preference for high accuracy in diagnosis prior to further intervention.…”

Endoscopic Evaluation of the Infratemporal Fossa

“…Other tests that may support the diagnosis include a glucose test and, more specifically, a beta-2 transferrin immunoelectrophoretic assay. 6 Cisternography can aid in the identification and localization of a CSF leak; intrathecal fluorescein injection is helpful mainly in identifying the presence of a leak and is limited in facilitating localization. 7 In terms of treatment, endoscopic repairs of CSF leaks have been successfully performed 8 -10 and the use of intrathecal fluorescein has been reported in Europe to help in such repairs.…”

Beta‐2 transferrin is detectable for 14 days whether refrigerated or stored at room temperature

“…Patients with clear rhinorrhea suspicious for nasal cerebrospinal fluid (CSF) leak should generally first have laboratory confirmation that the drainage is CSF before subsequent imaging is performed. One of the most sensitive and specific tests for confirming the presence of CSF is the beta‐2 transferrin test, with sensitivity ranging from 87% to 100% and specificity from 97% to 100% . Beta‐2 transferrin is a glycoprotein found in CSF, perilymph, and aqueous and vitreous humor.…”