This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Death and postmortem changes, Subject name: Forensic Medicine
CSF is stored at 
Select and explain. 
A. Room temperature, B. -20degC, C. 4degC, D. -70degC
C: 4degC
Answer: C: 4degC 
Explanation: BLOOD, URINE, VITREOUS AND C.S.F. All arecollected for biochemical examinations. Blood should be collected from the femoral vessels. Other sites, in descending order of preference are the subclavain vessels, root of aoa, pulmonary aery, superior vena cava and the hea. When blood samples are collected for volatile substances, small glass bottles with aluminium foil-lined should be used, which should be filled to the top to avoid loss of volatile substances into the head space and stored at 4degC. CSF is collected by lumbar or cisternal puncture. They are of value if collected within 4 to 6 hours after death, but not later than 12 hours. Ref:- k s narayan reddy; pg num:-123