Sample collection in Alcohol poisoning | Toxicology | Forensic Science

blood samples :
There is no prohibition of taking blood from any part of the body. Usually blood from cubital vein.
Only qualified person should take sample in the presence of officer.
Take two samples of blood, 5ml each preserve with 100mg of sodium fluoride.
Disinfect the skin with non alcoholic disinfectant eg- mercury chloride.
Postmortem blood sample should collected with in 2 days after death.
Blood from two different body parts collected CSF and vitreous humor provides better sample.

Urine sample :
Easy to collect and just after capture it might not give true index of it.
The aapke should be collected after half to one hour.
0.2% fluoride is used to preserve the urine sample.

Saliva sample:
Not used many times but for collection of samples paraffin is given for chewing. It causes salivation.

Breathe sample :
Only alveolar air should be collected and taken into consideration.
The air use to be in the equilibrium with blood alcohol level. Normal breath is with alveolar air thus it dilutes the amount of alcohol.
Collect total exhale gases, assume 2/3 alveolar air.
Or assume exhale gases contain 5.5% CO2 and calculate alveolar air on its basis.
Collect the last portion of forced air coz that might be the alveolar air.