This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Antigen-antibody reaction, Subject name: Microbiology
[{'content': 'Agglutination test in CSF sample is done for - \nSelect and explain. \nA. Streptococcus, B. Candida, C. Cryptococcus, D. Histoplasma', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Cryptococcus Laboratory diagnosis of crvptococcal infectiono Lumbar puncture is the single most useful diagnositc testo Following tests are usedA) Serology# The most useful serological test is LPA test (Latex agglutination test for the detection of cryptococcal polysaccharide capsular antigen).# This is highly specific and sensitive; and gives better results than direct microscopy and cultures.B) Direct microscopy# Unstained wet preperations of CSF mixed with drop of India ink or nigrosine demonstrate the capsule as a clear halo.# Methenamine silver or periodic acid-Schiff are used for staining a tissue sample.C) Culture# Can be easily cultured from CSF on sabouroud's agar.", 'role': 'assistant'}]