Biochemist Expert Witness

Introduction

A biochemist expert witness applies specialist knowledge of chemistry, biology and laboratory science to evidence arising in legal proceedings. Their expertise may be relevant where cases involve laboratory results, drugs, metabolites, toxins, hormones, proteins, enzymes or other biochemical substances.

Experts may have backgrounds in clinical biochemistry, analytical biochemistry, toxicology or pharmaceutical science. Qualifications can include a BSc, MSc or PhD, HCPC registration as a Clinical Scientist and Fellowship of the Royal College of Pathologists. The expert selected should have experience directly relevant to the scientific questions in the case.

Biochemists will commonly undertake a desktop assessment, reviewing laboratory and documentary evidence without physically examining the individual.

Typical Case Types

Clinical Negligence and Civil Court

Biochemists may be instructed in clinical negligence claims where laboratory testing, interpretation or reporting is relevant to alleged breach of duty and/or causation. This may include delayed, incorrect or missed laboratory results; inappropriate testing strategies; analytical errors; incorrect reference ranges; failure to recognise significant biochemical abnormalities; specimen handling problems; or questions concerning the reliability of laboratory investigations.

Cases may involve renal or liver function, electrolytes, glucose, endocrine investigations, metabolic disorders, therapeutic drug monitoring, toxicology or other biochemical testing.

The expert may consider whether laboratory practice met the standard reasonably expected at the relevant time and whether an alleged analytical or reporting failure contributed to the outcome. Clinical questions outside the biochemist’s expertise may require separate medical expert evidence.

Civil expert evidence is governed by CPR Part 35 and Practice Direction 35. The expert’s overriding duty is to assist the court independently.

Criminal Court

A biochemist may assist where proceedings involve drugs, alcohol, poisons, toxic substances or disputed laboratory evidence. Instructions may concern blood or urine analysis, toxicology findings, therapeutic versus toxic concentrations, metabolites, novel psychoactive substances, poisoning or analytical techniques such as LC-MS/MS, GC-MS and immunoassay.

The expert may consider sample integrity, analytical interference, detection limits, calibration, quality control and chain of custody. Criminal expert evidence must comply with Criminal Procedure Rules Part 19 and, where applicable, the Forensic Science Regulator’s requirements.

Family Court

Biochemical evidence may be relevant to drug and alcohol testing, medication, toxic exposure, metabolic abnormalities, prenatal or neonatal drug exposure, poisoning allegations or fabricated or induced illness.

The expert may consider whether laboratory findings support a proposed explanation or whether conclusions drawn from testing are scientifically justified. Expert evidence in family proceedings is governed by Family Procedure Rules Part 25.

Coroners’ Courts

Biochemists may assist where laboratory evidence is relevant to how a person came by their death. Cases may involve suspected overdose, poisoning, drug interactions, metabolic abnormalities or interpretation of biochemical results preceding death. Post-mortem toxicology can also require consideration of decomposition, redistribution and specimen integrity.

Role, Evidence and Reporting

The biochemist explains the significance, reliability and limitations of scientific evidence. Relevant considerations may include analytical methodology, metabolites, pharmacokinetics, sensitivity and specificity, limits of detection and quantification, measurement uncertainty, cross-reactivity, interference and sample collection or storage.

Records may include laboratory and toxicology reports, clinical records, medication charts, post-mortem reports, sample information, laboratory methodology, quality-control documentation and other expert reports.

A report will typically address the expert’s qualifications, instructions, evidence reviewed, methodology, findings, interpretation, alternative explanations, limitations and conclusions. The expert must distinguish between association, compatibility and causation, remain within their area of competence and provide an independent opinion irrespective of the instructing party.