A patient has bloody drainage from the ear after head injury. To determine whether CSF is present in the drainage, which nursing action is most appropriate?

• A. Examine the tympanic membrane for a tear
• B. Test the fluid with a glucose identifying strip or stick
• C. Test the fluid for a halo sign on a white dressing
• D. Collect 5 mL of fluid in a test tube and send it to the laboratory for analysis

Answer: (C)

The main concept is recognizing CSF leakage at the bedside by looking for a specific dressings sign. When CSF drains from the ear after head injury, a clear ring or halo can form around the central bloody drainage on a clean white dressing. That halo happens because CSF, which contains glucose and other fluids, diffuses into the surrounding blood, creating a distinct ring. This bedside cue is quick and noninvasive, helping you identify CSF leakage promptly and guiding immediate care to protect the patient from infection and further complications.

This sign is the best initial action because it provides a rapid, visible indication of CSF without waiting for laboratory tests or invasive sampling. It also helps you reinforce appropriate precautions, like keeping the head midline, avoiding pushing on the ear, and informing the care team for appropriate diagnostic imaging and management.

Examining the tympanic membrane might show a rupture but doesn’t confirm CSF in the drainage. Glucose test strips can be helpful in some settings but may be unreliable or inconclusive on contaminated drainage. Collecting fluid and sending it to the lab delays diagnosis and treatment. The halo sign offers the quickest, most practical bedside clue to CSF leakage.