Etiology | Availability* | When inclusion of NAT is indicated | Preferred testing method(s)¶ |
Bacteria |
AbscessΔ | Limited | Gram stain positive, culture negative; prior antibacterial therapy | Gram stain, culture prior to antibacterial therapy |
Mycobacterium tuberculosis◊ | Yes | Potentially | AFB stain, culture, histologic exam, and NAT |
Viruses |
Epstein-Barr virus (primary central nervous system lymphoma) | Yes | Yes | NAT, preferably quantitative |
JC virus (progressive multifocal leukoencephalopathy) | Yes | Yes | NAT, preferably quantitative |
Spirochetes |
Treponema pallidum (syphilis) | Limited | No | Serology, CSF VDRL |
Fungal |
Cryptococcus | Yes | No | Antigen detection, culture |
Other | Limited | Rarely | Culture, serology, histologic exam |
Parasites | Limited | Rarely (eg, amebic brain abscess or immunocompromised hosts) | Stains, serology, histologic exam, and NAT for select pathogens |