CALCA and viral encephalitis: Last, a prospective observational study published by Li et al. in 2017 included 143 ICU patients (49 with BM, 25 with TBM, 34 with viral meningitis/encephalitis (VM/E), 15 with autoimmune encephalitis (AIE), and 20 with non-inflammatory nervous system diseases (NINSD) to assess the value of CSF PCT, S–PCT and other biomarkers in the diagnosis of BM.