This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Poisoning, Subject name: Forensic Medicine
In chronic arsenic poisoning the following samples can be sent for laboratory examination, except - 
Select and explain. 
A. Nail clipping, B. Hair samples, C. Bone biopsy, D. Blood sample
D: Blood sample
Answer: D: Blood sample 
Explanation: Arsenic is rapidly cleared from blood.so a blood sample is only useful for acute poisoning Ref: K.S.Narayan Reddy's Synopsis of Forensic Medicine and Toxicology, 29th edition, Chapter 26, page 295.