This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Rapid diagnostic test for gram negative bacterial Meningitis is 
Select and explain. 
A. CSF - Latex agglutination, B. Nasopharyngeal swab culture, C. CSF - Culture, D. Limulus amebocyte lysate assay
D: Limulus amebocyte lysate assay
Answer: D: Limulus amebocyte lysate assay 
Explanation: Limulus amebocyte lysate reacts with bacterial endotoxin lipopolysaccharide, which is a membrane component of gram - negative bacteria.