TYPES OFRESULTS Accurate Inaccurate 1 False positive results

TYPES OFRESULTS • Accurate • Inaccurate 1. False positive results 2. False negative results • False positive and false negative results are known as Fallacies in toxicological results which may be due to some artefacts. • Artefact is a fact which is not a fact. `

FALLACIES IN RESULTS OR TOXICOLOGICAL ARTEFACTS • Production of alcohol due to enzymatic decomposition of proteins because of putrefaction (less than 100 mg%) • Increase in concentration of carboxy Hb (19 -25%) • Production of cyanide due to decomposition (up to 10 mg%) in three months old blood

• Combustion of body tissues and other materials yield several gases, which are NH 3 CO, HCN, H 2 S, SO 2, NO, NO 2, NO 3 (as silk and wool nitrogen content is high) • Burn victims contained increased level of cyanide between 17 - 220 mg per 100 ml • Faulty technique in collection storage or use of preservative • Collection of blood from heart may get diluted due to pericardial fluid. Use of EDTA, Formalin, heparin or use of spirit may give false positive result for alcohol or methanol

• Use of contaminated bottles for collection of viscera in single bottle • Use of contaminated instruments • Use of contaminated preservatives • In buried bodies, arsenic and other toxicological elements may be imbibed from the surrounding earth may result in inaccurate toxicological analysis • Improper sealing or tightening the containers not properly may result in evaporation of volatile poisons resulting in false negative results.