Cerebrospinal Fluid Findings are Poor Predictors of Appropriate FilmArray Meningitis/Encephalitis Panel Utilization in Pediatric Patients.

Molecular testing of cerebrospinal fluid (CSF) using the BioFire FilmArray® Meningitis/Encephalitis (FA-M/E) panel permits rapid, simultaneous pathogen detection. Due to the broad-spectrum of targeted organisms, FA-M/E testing may be restricted to patients with abnormal CSF findings. We sought to determine if restriction is appropriate in our previously healthy and/or immunocompromised pediatric patients. FA-M/E was ordered on 1025 CSF samples from 948 patients; 121 (11.8%) specimens were FA-M/E positive. Of these, 89 (73.6%) were viral-positive and 30 (24.8%) were bacterial-positive. The most common targets detected were enterovirus (n=38), HHV-6 (n=30), and Streptococcus pneumoniae (n=14). Pleocytosis with white blood cell (WBC) levels of ≥5 cells/mm3 and ≥10 cells/mm3 were found in 33.1% and 24.3% of all specimens, respectively. Using WBC ≥5 cells/mm3, 63.4% (59/93) of positive specimens exhibited pleocytosis compared to 29.5% (233/789) of negatives. Among positives, 54.4% (37/68) of viral and 87% (20/23) of bacterial had pleocytosis. Using a pleocytosis cutoff of ≥10 cells/mm3 would have missed an additional enterovirus, one CMV, and two HHV-6. CSF glucose and protein levels were normal for 83/116 (75.2%) and 51/116 (44%) positives. Abnormal glucose in combination with WBC ≥10 cells/mm3 showed high specificity (94.5%) and was a better predictor of FA-M/E positivity than abnormal protein. Sensitivity and positive predictive values were