Gu W, Rauschecker AM, Hsu E, et al. - This case-control study demonstrated that CSF metagenomic next-generation sequencing (mNGS), which has low specimen volume requirements, does not require cell integrity preservation, and was originally developed to diagnose neurologic infections, can also detect genetic evidence of a CNS malignant neoplasm in patients who had negative CSF cytologic testing and/or flow cytometry results with a low risk of false-positive results.

• The sample consisted of 130 candidates (median [interquartile range] age, 57.5 [43.3-68.0] years; 72 men [55.4%]).

• The researchers employed 125 residual laboratory CSF specimens from 47 patients with CNS malignant neoplasms and 56 individuals with other neurological disorders in the test performance study.

• Twelve patients and seventeen matched control volunteers were involved in the neuroinflammatory disease study.

• The CSF mNGS assay had a sensitivity of 75% and a specificity of 100%.

• Aneuploidy was found in 64% of patients in the test performance study who had nondiagnostic cytologic testing and/or flow cytometry and in 55% of patients in the neuroinflammatory disease study who were eventually identified with a CNS malignant neoplasm.

• Of the patients with aneuploidy, 38 (90.5%) showed multiple copy number variants, with tumor fractions ranging from 31% to 49%.