In chronic arsenic poisoning the following samples can be sent for laboratory examination, except -
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.
Nail clipping
Hair samples
Bone biopsy
Blood sample
Poisoning