- CSF-ADA levels are significantly elevated in tuberculous meningitis and meningococcal meningitis compared with non-infectious controls.
- Proposed cutoffs: 5.5 IU/L for Mycobacterium tuberculosis (sensitivity 61.2%, specificity 72.4%); 7.3 IU/L for CNS coinfections.
- CSF-ADA correlates positively with CSF protein and weakly negatively with CSF glucose, supporting its use as a supportive diagnostic tool.
Arq Neuropsiquiatr. 2026 Nov;84(11):1-11. doi: 10.1055/s-0046-1829158. Epub 2026 Oct 27.
ABSTRACT
BACKGROUND: Adenosine deaminase (ADA) levels in the cerebrospinal fluid have neither been validated as a reliable diagnostic marker nor sufficiently studied in patients with tropical diseases and human immunodeficiency virus (HIV) infection.
OBJECTIVE: To investigate cerebrospinal fluid (CSF)ADA levels in different central nervous system (CNS) infections, define a cutoff value, and assess correlations between CSF-ADA and other laboratory parameters.
METHODS: In 206 patients whose CSF-ADA levels were measured, we analyzed data on baseline characteristics, diagnoses, CSF-ADA levels, and additional laboratory parameters. These CSF-ADA levels were compared according to microbiological diagnosis, and correlations with other CSF and blood parameters were analyzed.
RESULTS: Compared with the non-CNS infectious control group (n = 40), 2 subgroups showed significantly higher CSF-ADA levels: Mycobacterium tuberculosis (n = 45, p < 0.0001) and Neisseria meningitidis (n = 11, p = 0.0400). The identified cutoff values were 5.5 and 7.3 IU/L for M. tuberculosis and CNS coinfections, respectively. For M. tuberculosis, sensitivity was 61.2% and specificity was 72.4%, whereas coinfections demonstrated 50% of sensitivity and 82.8% of specificity. The CSF-ADA levels correlated positively with CSF protein (Spearman rank correlation coefficient [rs] = 0.3009, p < 0.0003) and weakly correlated negatively with CSF glucose (rs = -0.1895, p < 0.0254). Patients with M. tuberculosis infection exhibited significantly higher CSF-ADA levels, as reflected by the mean, median, and standard deviation, than those with other infectious etiologies combined (n = 121) and those with bacterial and viral infections analyzed separately (p < 0.05). When stratified according to HIV status, a significant difference in CSF-ADA levels was observed only among patients with varicella-zoster virus infection (p = 0.0428).
CONCLUSION: The CSF-ADA levels were elevated in tuberculous and meningococcal meningitis. Higher cutoff values may occur in CNS coinfections. Therefore, CSF-ADA may serve as a supportive diagnostic tool in cases of suspected TBM, meningococcal meningitis, and CNS coinfections.
PMID:42946005 | DOI:10.1055/s-0046-1829158
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