Testing the drainage from suspected CSF otorrhea or rhinorrhea for CSF involves looking for what sign?

Testing the drainage from suspected CSF otorrhea or rhinorrhea for CSF involves looking for what sign?

• A. Testing for a halo sign on a white dressing indicates CSF presence
• B. Examining the tympanic membrane for a tear
• C. Using a glucose strip will always identify CSF reliably
• D. Sending the fluid to the lab for analysis is the first step

Answer: (A)

When CSF drainage is suspected, a halo sign on a white dressing is the key bedside clue that cerebrospinal fluid is present. The CSF mixes with any blood from the leak and forms a clear ring around the central bloody stain, so you see a distinct halo rather than just a single red spot. This pattern helps differentiate CSF from other types of drainage like pure blood or mucus and provides a rapid, noninvasive cue for further evaluation. Keep in mind that this sign is helpful but not definitive. For confirmation, labs can test for CSF-specific markers such as beta-2 transferrin. Glucose test strips are not reliable for identifying CSF in real-world conditions because results can be affected by blood or other nasal/mucous secretions. Simply examining the tympanic membrane may miss a CSF leak, and sending fluid to the lab is important, but the halo sign gives an immediate, practical clue at the bedside.

When CSF drainage is suspected, a halo sign on a white dressing is the key bedside clue that cerebrospinal fluid is present. The CSF mixes with any blood from the leak and forms a clear ring around the central bloody stain, so you see a distinct halo rather than just a single red spot. This pattern helps differentiate CSF from other types of drainage like pure blood or mucus and provides a rapid, noninvasive cue for further evaluation.

Keep in mind that this sign is helpful but not definitive. For confirmation, labs can test for CSF-specific markers such as beta-2 transferrin. Glucose test strips are not reliable for identifying CSF in real-world conditions because results can be affected by blood or other nasal/mucous secretions. Simply examining the tympanic membrane may miss a CSF leak, and sending fluid to the lab is important, but the halo sign gives an immediate, practical clue at the bedside.