Guidelines for Obtaining Specimens for Post mortem Toxicological Analysis

Liver

This is available from almost all cases and can be collected easily. As it is the primary metabolic organ, drugs are often found in higher concentrations than in the blood. Liver should be submitted in cases in which little or no blood can be obtained. Approximately 10g of wet, unfixed, tissue should be placed in a plastic or glass container. Data suggest that concentrations can vary depending on the site from which the liver specimen is collected. It is recommended that the right lobe be sampled to reduce contamination from bile and redistribution artefacts from the stomach contents.

Other Tissues

Other solid tissues may be used for drug analysis. However there are few data on the significance of these results. Muscle may be submitted in the absence of liver while other tissues can be useful in investigating deaths involving volatile substance abuse (see below). 

Stomach Contents

10-20mL stomach contents should be collected into a plastic or glass container without preservative. This matrix is useful in cases of oral overdose in which large amounts of unabsorbed drug remain in the stomach, as concentrations are substantially higher than in any other fluid. If recognisable tablets or capsules are found, these should be removed and placed in separate containers for identification.

Larvae

Entomotoxicology is still a relatively novel area of toxicology. It involves the study of drugs and poisons in insects feeding on decomposing bodies, and offers a number of technical advantages over putrefied human remains. The extraction of drugs from larvae is the same as that from tissue but, usually, no emulsion is formed, whereas this is not always the case with human tissue. There is also less contamination observed from endogenous substances, which is particularly problematic with putrefied human remains. It is possible that secondary bioaccumulation of drugs in larvae may also occur. Larvae are usually present in abundance on decomposed bodies and sampling is often a relatively straight forward procedure. The larvae should be placed directly into as many plastic tubes as is necessary. To date, most investigators have found no correlation between drug concentrations in larvae and those in human tissues. However, the full range of drugs that can be identified in larvae and the potential qualitative application of entomotoxicology have still to be fully documented.

Syringes

Syringes MUST be packed with care and any needles protected by a suitable plastic shield to prevent injury. Please advise the laboratory if you intend to submit sharps.

Specialist Analyses:

In addition to the nominal specimens, submit a minimum of 5mL blood in a glass tube with minimal head space. Brain, adipose tissue, lung and kidney are useful for the investigation volatile substance deaths. 10g of tissue should be collected and placed in separate glass jars or nylon bags.

Volatile Substances (Solvents)

Insulin or Diabetes Related Deaths

The analysis of vitreous humour for glucose, lactate, acetone, insulin and C-peptide and blood for HbA1c (glycated haemoglobin) can provide an indication of ante mortem glycaemic control. Please submit 2mL vitreous humour in 2% sodium fluoride tube in addition to the nominal samples.

The volumes indicated above are the ideal, to ensure optimal sensitivity and to enable repeat analysis if required. Reduced sensitivity and scope of screening may result from smaller volumes. However, smaller volumes may be sufficient and should always be submitted.

Please ensure that all specimens are clearly labelled with the full name of the deceased, if known, the post-mortem date, sample type, mortuary and name of pathologist. In the case of blood specimens, please indicate the exact site of collection if not femoral blood. The specimens should be placed in sample bags that separate any paperwork from the specimens.

DO NOT

send more than one case in the same sample bag.

Please submit a ‘Pathologist Analysis Request Form’ and ‘Coroner’s Officer Report’ with each case referred to the service.

Pathologist Analysis Request Forms

Please download these guidlines

Please download these guidlines

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Bioanalytics and Forensic Toxicology