(c) Toxicology (including biochemistry): Communication with the testing laboratory is very important. The fluids and volumes required, and the tissue required (if any), will vary from laboratory to laboratory. In all cases, the site from which the specimen has been obtained must be carefully recorded (i) Blood: If possible, at least 10 ml, preferably obtained from a peripheral site (e.g. the femoral vein) prior to the commencement of the autopsy. To avoid post collection fermentation and putrefaction, add 1% w/v sodium fluoride (NaF) to the collection tube. If peripheral blood is not available, a central site (e.g. the heart) can be used. As a last resort, blood from a body cavity can be obtained, although this will almost certainly be contaminated owing to leakage from other structures (e.g. stomach or bowel contents, mucus, urine, pus or serous fluids) and thus the interpretation of the results will be seriously compromised (ii) Urine:116 If possible, at least 10ml is usually obtained by direct needle puncture of the exposed bladder after the abdomen has been opened. Alternatively, a urinary catheter inserted via the urethra can be used (iii) Vitreous Humour:117 2–3 ml can be obtained by needle puncture of each globe. As it is relatively viscous, a 15- or 17-gauge needle should be used (iv) Bile: Up to 10 ml (v) Tissue: Liver, muscle, kidney, brain, adipose tissue (if possible, 100 mg of each), skin site (e.g. if an insulin injection is suspected). The tissues should be placed in separate, clean, glass or plastic jars without a fixative. Consider freezing the samples if delays are anticipated before transport to the laboratory, or before analysis If volatile substance inhalation is suspected, an entire lung should be taken and sealed in a nylon bag. (Polyethylene/plastic bags are permeable to volatile substances) 44 (vi) Stomach contents: Ideally, prior to removing the abdominal contents, the stomach can be isolated by clamping or tying the lower oesophagus and duodenum. After removal, the stomach should be opened inside a large clean dish. After describing and photographing the contents, submit them in secure, clean, screw-top glass or plastic jars (vii) Hair and fingernails: These may be useful in cases of heavy-metal poisoning or certain drugs. Obtain hair samples by plucking the hair, thereby including the root; do not cut with scissors. Nail samples should comprise the whole nail. (d) Microbiology: This is not a routine autopsy investigation but can be useful if the collection technique is good and samples are collected in the early post-mortem period. Differentiating between pathogens and normal post-mortem flora complicates the assessment of results. Possible samples include: (i) Blood, taken using a sterile needle and syringe under direct vision from the femoral vein or artery (or other suitable vessel), accessed in a sterile manner prior to commencing the autopsy (ii) Sampling a small piece of tissue (e.g. lung, spleen) under conditions that are as sterile as possible The specimen should be taken to the microbiology laboratory without undue delay. Otherwise, the specimen should be kept in a refrigerator until (the earliest possible) transfer. (e) Entomology: The collection of appropriate samples of larvae, beetles, flies and other insects on or in the body requires consultation with an entomologist. This includes eggs, maggots and pupae as well as adult insects. Samples may be useful for toxicological analysis as well as helping to assess the minimum post-mortem interval and/or possibly to assess whether the body has been moved some distance after death 116 These samples can be used for biochemical testing. Assessments of hyperglycaemia, ketosis, renal failure and/or dehydration (among other things) can sometimes be made from analysis of these specimens. 117 Forensic Autopsy: Manual for Forensic Pathologists, UN Office on Drugs and Crime. The Minnesota Protocol on the Investigation of Potentially Unlawful Death (2016)