A patient with a head injury has bloody drainage from the ear. To determine whether CSF is present in the drainage, the nurse should

• A. Examines the tympanic membrane for a tear
• B. Tests the fluid for a halo sign on a white dressing
• C. Tests the fluid with a glucose identifying strip
• D. Collects 5 mL of fluid in a test tube and sends it to the laboratory for analysis

Answer: (B)

When a patient has head trauma with ear drainage, the key finding is identifying CSF leakage from the ear. The quickest, bedside clue that CSF is present is the halo sign on a white dressing. Clear CSF that seeps onto a bloody dressing tends to diffuse into the surrounding blood, forming a yellowish ring around the blood stain—the halo. This visual cue is a strong, immediate indication that cerebrospinal fluid is involved, which also points to a basilar skull fracture.

While testing the fluid for glucose can help confirm CSF, the halo sign provides an immediate, noninvasive clue right at the bedside. Examining the tympanic membrane isn’t reliable for confirming CSF in drainage, and sending a sample to the lab for analysis takes time and isn’t as rapid a bedside indicator.