<prompt> Agglutination test in CSF sample is done for -StreptococcusCandidaCryptococcusHistoplasma  <response>: 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 sabourouds agar. 