After a history of Neisseria infection, what should be tested for next?

• A. HIV
• B. Complement levels
• C. Lupus anticoagulant
• D. Complete blood count

Answer: (B)

Following a history of Neisseria infection, testing complement levels is particularly relevant due to the association between Neisseria infections and complement deficiencies. Individuals with deficiencies in the terminal complement components (specifically, C5, C6, C7, C8, and C9) are at an increased risk for recurrent infections by Neisseria species, as these complement proteins are crucial for opsonization and clearance of Neisseria bacteria.

Assessing complement levels can help identify such deficiencies and guide appropriate clinical management, including the potential need for prophylactic antibiotics or other preventative measures for these individuals. Understanding this connection underlines the importance of ensuring that patients are adequately screened for complement system functionality after experiencing a Neisseria infection, as well as recognizing the role of the immune system in such infections.