Post-Mortem Examination and Viscera Collection in Poisoning

The examination begins with the body's identity, condition, available history and any documented changes during resuscitation or transport. Record clothing, medical devices, injuries and relevant external findings with their actual location and appearance. Observation and interpretation should remain distinguishable in the notes.

Lividity colour, oral injury, residue, injection sites and skin contamination may inform a differential diagnosis. They are neither sensitive nor specific enough to identify a poison alone. Bright coloration can have several explanations, and its absence does not exclude carbon monoxide or cyanide exposure.

Odour is a limited incidental observation, not a procedure for testing a suspected chemical. Do not deliberately sniff a body, gastric material or container to identify an agent. Hazardous gases may be present, and an absent or unrecognised smell is not a negative toxicology result.

Pupil findings after death must not be treated as a direct reproduction of a bedside toxidrome. Treatment, post-mortem changes and other conditions affect appearance. Clinical observations made before death may be important, but their time and relationship to medication should be recorded.

Injection marks or patches can support further investigation without proving the substance, route or timing of a fatal exposure. Preserve relevant materials and request appropriate analysis where justified. The same restraint applies to tablets or coloured material visible around the mouth.

Specimen selection should follow the question. Blood is often important for quantitative interpretation; urine may broaden evidence of exposure; gastric contents may contain unabsorbed material. Tissues can supplement or replace unavailable fluids, but their results are not interchangeable with blood concentrations.

Select and label the actual anatomical source. Liver is not simply the organ with the highest concentration of every poison, and kidney is not a universal record of an excretion phase. Organ distribution depends on the substance, time, physiology and post-mortem conditions.

As a published US example, ANSI/ASB BPR 156 (2023) gives a post-mortem collection table that includes blood, urine, vitreous, tissues, gastric contents and other supplementary material. It explicitly requires laboratory communication for targets with special requirements. Its suggested set is not a command to collect every listed matrix in every case.

The scientific plan should distinguish qualitative identification from quantification and biochemical testing. A specimen preserved for a drug assay may not suit a vitreous chemistry profile. An available antemortem hospital specimen can be valuable, provided its identity, collection time, treatment context and handling are established.

Gastric contents should be described and sampled according to the investigation and laboratory instructions, with total quantity documented where measured. Do not assume that the entire stomach must always be submitted together with its wall or that intestinal residue dates absorption precisely. Preserve the information about what was actually collected.

The purpose of preservation is to reduce unwanted change while retaining the information needed by the test. Microbial activity, chemical degradation, evaporation, adsorption and contamination can affect different analytes in different ways. No preservative prevents all of these processes.

Routine tissue fixation for histology and specimen preservation for toxicology are different tasks. Formalin can react with substances, affect extraction and introduce interfering components; some formulations contain methanol. Collect separate unfixed material for toxicology where required and document any accidental exposure to fixative.

Salt solution is part of some local viscera protocols, but is not a universal global default. Similarly, sodium fluoride and an anticoagulant may be specified for particular blood submissions without making that tube suitable for every metal, gas, drug or biochemical assay. Confirm the actual tube and additive rather than relying on cap colour alone.

The closure and container must suit the target. Volatile compounds need attention to sealing, headspace and loss during handling; trace-metal work needs suitable low-background materials. Repeated opening, transfer and uncontrolled thawing can change a limited specimen. Do not assert that every plastic container loses every volatile compound within one fixed interval.

Storage conditions and transit time should follow analyte- and laboratory-specific instructions. Refrigeration, freezing and room-temperature storage serve different purposes for different specimens. If glass is frozen, breakage risk must be managed. Record a deviation so the analyst can assess it rather than promise one shelf life for all viscera.

Where special collection is required for cyanide, phosphine, toxic alcohols or another unstable target, consult the laboratory before routine processing consumes the material. A standard drug panel or ordinary organ jar cannot be assumed to address these exposures.

The collection plan should reduce contamination between specimens and preserve their sources. Qualified personnel follow their applicable autopsy procedures, using appropriate clean equipment and documenting the sequence. Relevant sampling may be undertaken before extensive dissection or organ manipulation where this helps avoid contamination.

Record the deceased's identifier, examination or case number, specimen type, anatomical site, collection time and collector. Add preservatives and measured quantity where known. A label saying blood without its source loses information that cannot be recovered from the instrument result.

Record central and peripheral blood separately. Do not pool them and later call the mixture femoral blood. Likewise, a mixture of several organs is a composite specimen with limited source attribution, not several independent tissue results.

Sealing must be tamper-evident and follow the receiving service's procedures. Document the seal and the package condition, provide suitable secondary protection, and record every transfer with the relevant identities and times. Wax, cloth and a particular national form are not universal scientific requirements.

The referral should include circumstances, symptoms before death, relevant pathology, treatment, suspected exposures and requested tests. Clinical treatment can explain an analyte or change its concentration. An undocumented resuscitation drug should not be mistaken for evidence of a pre-event exposure.

At receipt, discrepancies, leakage, inadequate volume or unsuitable preservation require assessment and communication. The laboratory may be able to answer a narrower question, request alternative material or explain why a test cannot be performed. A defect should be documented rather than automatically translated into a guaranteed legal outcome.

After death, loss of normal physiological barriers and concentration gradients can change the distribution of some substances. Movement from tissue reservoirs into nearby blood is one mechanism of post-mortem redistribution. Drug properties, anatomical site, interval, decomposition and handling can all influence the measured result.

Peripheral blood is often preferred for interpretation because it is less directly exposed to some central tissue reservoirs. It is still a post-mortem specimen. Collection before extensive dissection cannot prevent changes that already occurred, and the source and method of collection remain important.

Do not assign all lipophilic drugs one redistribution factor or declare every water-soluble compound unaffected. Central-to-peripheral ratios can vary between substances and cases. A measured ratio is not a universal correction formula that reconstructs an antemortem concentration.

Other changes also matter. Microbial activity may affect alcohol interpretation, unstable analytes may decline, and treatment or a prolonged interval before death can change the available picture. Blood, urine and vitreous provide complementary evidence rather than one automatically decisive comparison.

Reference concentrations require matching the matrix, units and case context. A range derived from living plasma is not automatically valid for post-mortem whole blood or tissue. Overlap among therapeutic use, toxicity and fatal cases limits conclusions from a concentration alone.

Interpret the result alongside pathology, circumstances and clinical history. The final opinion may support exposure or a possible contribution while leaving the degree of contribution unresolved. It should not estimate an exact administered dose or certify manner from one organ result.

A missing or ambiguous label threatens specimen attribution. A wrong preservative can threaten analytical validity. A long warm interval may threaten stability. These are different problems and should be described separately, with their likely effect on the requested examination.

Limited volume may restrict repeats, additional analytes or independent examination. It does not necessarily make an initial valid identification meaningless. Discuss priorities before consuming material, retain appropriate portions where required, and state when a specimen was exhausted.

In a decomposed or extensively injured body, preferred specimens may be unavailable. Alternative tissues or fluids can still provide information when tested appropriately. Their limitations should accompany the result, and a cavity fluid must not be mislabelled as intact peripheral blood.

A negative result must be read against the analytical scope, sensitivity and specimen condition. It does not exclude a target that was not tested or a substance that may have disappeared before collection. Conversely, a degraded specimen is not grounds to assume an unmeasured poison was present.

A practical check before dispatch asks whether the question, specimen identity, anatomical site, collection details, preservation, hazards, storage and handover records are adequate. This supports later interpretation without claiming that one checklist guarantees a verdict.

The comparative specimen guide is Biological, Non-Biological and Viscera Matrices in Toxicology.

Host factors and post-mortem interpretation are developed in Factors Affecting the Intensity of Poisoning.

Scene material is handled separately as discussed in Crime Scene Investigation in Poisoning Cases.