Overutilization of cultures of CSF for mycobacteria
T. W. Crowson, E. C. Rich, B. F. Woolfrey and D. P. Connelly
Over a five-year period, 1,883 specimens were cultured for mycobacterium
tuberculosis (TB) at our hospital. All cultures were negative, and no cases
of tuberculous meningitis were diagnosed. Culture rates (percent of CSF
specimens cultured for TB) varied from 74% on the Medicine and Neurology
services to 6% on the Pediatric service. These culture rates have been
stable for five years. These data suggest that on the Medicine and
Neurology services, TB cultures of CSF are persistently overutilized. A
simple rule of not culturing CSF for TB if results of the CSF analysis are
normal (ie, WBC count less than or equal to 4/cu mm, protein level less
than or equal to 45 mg/dL, and glucose level greater than or equal to 45
mg/dL) could reduce utilization by at least 50% without adversely affecting
quality of care.
