SOURCES OF ERROR IN USE OF BETA-2 TRANSFERRIN ANALYSIS FOR DIAGNOSINGPERILYMPHATIC AND CEREBRAL SPINAL-FLUID LEAKS

Beta-2 transferrin is a protein found in cerebral spinal fluid and inn er ear perilymph, but not in blood, nasal, or ear secretions. The clin ical use of this test has been previously demonstrated, but sources of test error have not been addressed. The purpose of this study was to evaluate sources of error related to this test in order to improve its clinical use. We reviewed the specimens submitted for beta-2 analysis over the first 12 months of test availability at our institution to i dentify potential factors leading to test error. Sources of error were categorized into the following groups: sample collection, delivery, a nd extraction factors; assay factors; physician-related factors; and p atient-related factors. The test for beta-a transferrin is a valuable diagnostic tool for the management of difficult clinical problems, pro vided the physician is aware of potential factors that can lead to tes t error and clinical mismanagement.