Thread by @WKemp_MT_FPDoc

#forensics #toxicology
As requested, here are some suggestions/pearls regarding toxicology
@anueru432 @AnthraxRipple @bex674 @DrSidSeth @YuRoFi @MComptonMD @CollOrduna
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1. For collection, do not perform blind sticks of heart (i.e., through the chest wall)...

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...you might hit stomach. Subsequent analysis will reveal drug concentrations that do not reflect what was in blood.
2. While subclavian sticks are more acceptable, be wary of hitting airway-regurgitated stomach contents can be present in airway.

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3. Gray top tubes contain sodium fluoride, which prevents postmortem breakdown of some drugs-I have tested antemortem blood (in red top) from hospital which was negative for cocaine and postmortem blood (in gray top) from same individual was positive

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4. When you fill tube, just let the vacuum do the work drawing blood in-if you apply pressure with the syringe, force in more blood, and overfill the tube, the top can pop off during transport (i.e, sending blood via mail to an outside lab)

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5. While body cavity blood can be used for qualitative analysis (i.e., what drugs are present), using it for quantitative analysis (i.e., how much drug is present) should be done ONLY WITH VERY EXTREME CAUTION! (depending upon the circumstances)

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6. Always put vitreous fluid in a red top tube (empty tube)-if you put vitreous fluid in a gray top tube (which has sodium fluoride), you will get a very high concentration of sodium. Don't laugh-I have seen it done and interpreted as hypernatremia!

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7. Vitreous fluid can be used for identification of electrolyte abnormalities, including hypernatremia, hyponatremia, hyperglycemia, dehydration and some others (but, with very rare exceptions, not for hyperkalemia, hypokalemia, or hypoglycemia).

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8. Be familiar with postmortem re-distribution. In living person, drugs are at different concentrations in various areas (e.g., heart blood versus pulmonary blood versus liver), after death, these drugs can move between compartments (I liken it to diffusion...

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8. (con't)...with drug concentrations equalizing out). Because of postmortem redistribution, peripheral blood (e.g., femoral or iliac blood) is preferred for most analyses.

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9. If you examine body, even if you do not perform an autopsy, draw fluids for toxicology, even if you don't initially perform the analysis-the situation may change. I drew blood on a hospital autopsy once, and later needed it--the COD turned out to be a drug overdose!

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10. Always interpret toxicology results in context of history (including scene investigation) & autopsy findings. A 1.0 mg/L methamphetamine concentration could be a cause of death, or it could be another finding in an individual who died as the result of gunshot wound

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11. Heroin breaks down very rapidly in blood to its metabolites, including morphine & 6-monoacetyl morphine (6-MAM). 6-MAM is often only identified in urine (or vitreous).

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12...we can explore further; others can add
@bjmagnani @MLegiste @k_pinneri @NicoleJacksonMD