et al., 2010; Dinis-Oliveira et al., 2017; Belsey & Flanagan, 2016). However, such samples should be retained (2–8 or –20 °C) in case they are needed. The advantages and disadvantages of various specimens are detailed in Table 2.6. There are special considerations in sample collection and storage for metals/trace elements analysis (Section 21.2).
Information recorded on the sample container at the time the sample is collected should include the name of the patient (first and family or last name) and date of birth, patient/subject/animal number, the date and time of collection, and the sample type. Many laboratories will have a bespoke analysis request form to accompany the sample(s) on which this and any other appropriate information such as a note of any preservative added to the sample, site of collection of blood, etc. should be recorded (Box 2.2). The date and time of receipt of all specimens by the laboratory should be recorded and a unique identifying number assigned in each case.
Table 2.5 Sample requirements: post-mortem biochemistry and toxicology
| Sample | Notesa |
| Heart whole blood (right ventricle) | 20 mL unpreserved (normally qualitative toxicology only) |
| Jugular vein whole blood | 20 mL unpreserved (normally qualitative toxicology only) |
| Peripheral whole blood | 20 mL from femoral or other peripheral site ensuring no contamination from urine or from central or cavity blood. Collect one portion into 2 % w/v sodium fluoride and another into a plain tube |
| Urine | 20–50 mL if available (plain tube, no preservative unless a portion is required for ethanol measurement) |
| Gastric contentsb | 25–50 mL (plain bottle, no preservative; record the total weight or volume) |
| Vitreous humour | Maximum available, plain tube, separate specimens from each eye if feasible. Avoid excessive suction to minimize the risk of aspirating retinal fragments. Collect one portion into 2 % w/v sodium fluoride if for ethanol measurement |
| Cerebrospinal fluid | 5–10 mL, plain tube |
| Pericardial fluid | Maximum available, plain tube |
| Synovial fluidc | Maximum available, plain tube |
| Intra-osseous fluid | Maximum available, plain tube |
| Bile | Maximum available, plain tube |
| Liver and other tissues | Liver 10 g (deep inside right lobe), other tissues 10 g as appropriated |
| Scene residuese | As appropriate |
aSmaller volumes may often be acceptable, for example in the case of young children
bIncludes vomit, gastric lavage (SWO, first sample), etc.
cAlternative if vitreous humour not available
dBecause there is little information on drug distribution within solid tissues in man, collection of approximately 10 g specimens from several sites from organs such as the brain is recommended if the whole organ is available
eTablet bottles, drink containers, aerosol canisters, etc. should be packed entirely separately from biological samples, especially if poisoning with volatiles is a possibility
Table 2.6 Advantages and disadvantages of different sample types in analytical toxicology
| Specimen | Advantage | Disadvantage | Comment |
| Blood (plasma/serum or whole blood) | Detect parent compound. Interpretation of quantitative data | Limited volume. Low concentrations of many basic drugs and some other poisons | Interpretation of quantitative results from post-mortem blood may be difficult |
| Dried blood spot on filter paper | If known volume of venous blood added, then easy to store and transport (room temperature) | Almost impossible to get accurate volume of blood without use of a pipette or special device. Need analyte to be stable on the paper | Advocated for collecting capillary blood, but capillary blood not venous blood |
| Urine | Often large volume.High concentrations of many poisons, but sometimes only metabolites detectable | Not always available. Quantitative data not often useful | Standard sample for substance misuse screening |
| Gastric aspirate (stomach contents, SWO, vomit, etc.) | May contain large amounts of poison, particularly if ingested | If available, variable sample. Limited use if exposure is by inhalation or injection | Ensure no cross-contamination of other specimens during transport/storage/analysis |
| Oral fluid | Non-invasive. Qualitative information on exposure to many drugs | Variable sample hence little use for quantitative work. Low concentrations of many analytes | Interpretation of quantitative results may be difficult |
| Hair/nails or nail clippings | Usually available even if decomposition advanced | High sensitivity needed. May only give exposure data for the weeks/months before death. Susceptible to external contamination | Easy to store (room temperature) |
| Exhaled air | Non-invasive. Large volume available | Need live patient. Analyte must be volatile or present as an aerosol | Mainly used to assess ethanol ingestion, carbon monoxide exposure, and monitor volatile anaesthetics |
| Scene residues (tablet bottles, aerosol cans, etc. near patient) | May contain large amounts of poison | May not have been the poison taken | Ensure no cross-contamination of other specimens during transport/storage/analysis |
| Vitreous humour | May be used instead of urine if latter not available | Limited volume but normally two specimens | Analysis may be valuable to help interpret post-mortem blood data for ethanol and for some other compounds |
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