To investigate the diagnostic value of cerebrospinal fluid (CSF) analysis in postoperative intracranial infection.

A retrospective analysis was conducted on 1, 329 patients (with 1, 329 samples of CSF) who were admitted to Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University and underwent elective craniotomy from January 2017 to December 2017. The samples were divided into 2 groups based on the culture results: the infected CSF group (n=176) and the non-infected group (n=1, 153). Comparison was conducted on the glucose level (GLU), protein level (PRO), the counts of total cells and white blood cells (WBC) and the level of lactose (LAC) between the 2 groups.

There were significant differences in GLU, WBC and LAC between CSF infected and non-infected groups (all P<0.001). The diagnostic sensitivity of GLU<2.5 mmol/L for the infection with Gram-negative bacteria was 77.6%, and the specificity was 75.0%. The diagnostic sensitivity of LAC>5.0 mmol/L was 74.1% and the specificity was 74.2%. The sensitivity and specificity of WBC>1, 000×10⁶ cells/L for infection with Gram-negative bacteria were 67.3% and 71.4%, respectively.

The results have suggested the diagnostic values of CSF GLU, WBC and LAC in postoperative intracranial infection. The GLU<2.5 mmol/L, LAC>5.0 mmol/L and WBC>1, 000×10⁶ cells/L might be predictive for intracranial infections with Gram-negative bacteria.

Neurosurgical procedures; Central nervous system infections; Postoperative complications; Dignosis; Cerebrospinal fluid