CSF is preserved for examination in case of
High-Yield Explanation
Alcohol is evenly distributed throughout the body water, and crosses the blood brain barrier easily. Hence is detected in CSF. And so causes, dependence and tolerance. CSF should be drawn out as early as possible. There is sustained increase of potassium levels in CSF within 20 hrs after death. Ref: K.S,Narayan Reddy's Synopsis of Forensic Medicine and Toxicology, 29th edition, Chapter 29, page- 316.