Emedinews:Insights on Medicolegal issues: Estimation of blood alcohol

• About 3-4 ml of blood is drawn as sample.
• Chemically clean evacuated tubes of 5ml should be used to collect samples.
• Tubes should be water proof /not be vulnerable to freezing; they should have labels with identification codes.
• EDTA should be used as anticoagulant. Tubes with liquid EDTA /fluoride reduce the risk of hemolysis leads to altered results
• 2ml of 5% aqueous solution of sodium citrate containing 0.2% w/v of formaldehyde or 0.5% w/v of formalin solution must be added to prevent decomposition which leads to altered results
• Plastic vacuum tubes/ Plastic vacuum gel tubes are preferred to glass tubes. If vacuum tubes are not available or tubes are opened for freely flowing samples, stoppers which do not react with blood constituents should be available.
• Special boxes for tube transfer and storage, earmarked refrigerator/ freezer must be available in hospital conducting medicolegal cases.
• About 3-4 ml of blood is taken in a sterile 5ml injection vial (properly sealed and labeled) containing about 2ml of 5% aqueous solution of sodium citrate containing 0.2% w/v of formaldehyde (or 0.5% w/v of formalin solution).
• Two approximately 1cm x 1cm size blood stains are formed on clean cotton cloth/gauze pieces and, after they are dry, they are transferred to a sterile 10ml injection vial it should be properly dried, before packing to avoid decomposition and then sealed and labeled.
• Blood stains located on the body of an uninjured person are taken by rubbing with moistened clean cotton cloth pieces, it should be properly dried, before packing to avoid decomposition and then sealed and labeled.