In most cases
Lumbar puncture to obtain CSF for:
	Cell count with differential
	Gram stain
	Glucose level
	Protein level
	Bacterial cultures
Blood cultures for bacteria
Serum glucose level
Urine culture
Consider
Latex antigen test of CSF and urine for
	Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitidis, group B streptococcus
Polymerase chain reaction test of CSF for viruses (HSV, CMV, HIV, Enterovirus)
Viral cultures of CSF, urine, stool, nasopharynx
Serology for infectious etiologies as indicated by history or physical examination (maternal or infant)
Stain for acid-fast bacillus
CT scan of the brain with and without contrast, or MRI