Evaluation of cerebrospinal fluid white blood cell count criteria for use of the BioFire® FilmArray® Meningitis/Encephalitis Panel in immunocompromised and nonimmunocompromised patients

Abstract

We implemented the BioFire® FilmArray® Meningitis/Encephalitis Panel (MEP) with guidance for use based on patient age, cerebrospinal fluid (CSF) white blood cell (WBC) count and immune system status. MEPs results over 2 years (1/1/2017 to 12/31/18) were reviewed and clinical significance of positive MEP results in patients with CSF WBC ≤ 10 evaluated. Overall, 12% (51/453) of MEPs were positive with 4/184 (2%) positive in nonimmunocompromised (non-IC) with ≤ 10 CSF WBCs. Among positive results in non-IC patient with ≤10 CSF WBCs, none were judged clinically significant. Four of 6 results in immunocompromised patients with ≤10 CSF WBCs were clinically significant. Redundant testing was common and guideline adherence could have safely decreased MEPs use 41% saving >$56,000. Guideline adherence was poor and MEP use can be safely avoided in non-IC adults with <10 CSF WBC, but clinically significant results did occur in IC patients with low CSF WBC. Clinical decision support could reduce unneeded testing and result in significant cost savings.