Samples should not be collected from the [[external ventricular drainage cerebrospinal fluid collection bag]] due to the rapid [[degradation]] of cellular components. Though samples can be drawn from the distal port, white cell counts and cultures are often not accurate
((Wong FW. Cerebrospinal fluid collection: a comparison of different collection sites on the external ventricular drain. Dynamics. 2011 Fall;22(3):19-24. PMID: 21941814.)).