Confirming Nasal Fluid is CSF

Primary Diagnostic Test: β2-Transferrin Analysis

• β2-transferrin testing is the definitive laboratory test to confirm that nasal fluid is cerebrospinal fluid, with near 100% specificity and high sensitivity, as recommended by the American College of Radiology 1, 2, 3

Alternative Confirmatory Test

• DTPA cisternography is reserved for cases where insufficient fluid can be collected for β2-transferrin testing, with a sensitivity of 76-100% and specificity of 100% for confirming presence of CSF leak, as reported by the American College of Radiology 1, 3, 4, 5, 6

Clinical Algorithm

• If β2-transferrin analysis is positive, CSF leak is confirmed and imaging (HRCT) should be performed for localization, as recommended by the American College of Radiology 2, 3

β2‑Transferrin Testing for Diagnosis of CSF Rhinorrhea

Diagnostic Accuracy

• β2‑transferrin analysis is the most reliable laboratory test for confirming a cerebrospinal fluid (CSF) leak, demonstrating near 100 % specificity and high sensitivity, making it the preferred first‑line assay for suspected CSF rhinorrhea. 7

Sample Collection Considerations

• Accurate β2‑transferrin testing requires that the patient have active nasal drainage at the time of specimen collection; for intermittent leaks, multiple samples should be obtained during episodes of rhinorrhea to avoid false‑negative results. 7