Toxicology Co-Counsel for Drug and Alcohol Evidence

Toxicology co-counsel helps a legal team identify the scientific questions that matter, obtain the underlying laboratory evidence, evaluate expert opinions, and present complex drug or alcohol evidence accurately. The role is especially useful when a case turns on the difference between detecting a substance and proving timing, dose, impairment, or causation.

Science. Strategy. Trial Experience.

What does toxicology co-counsel do?

Toxicology co-counsel integrates legal strategy with forensic toxicology, pharmacology, analytical chemistry, and laboratory practice. The work can begin before experts are retained and continue through discovery, expert preparation, deposition, motion practice, and trial.

The precise role depends on the engagement. Co-counsel may advise the litigation team, coordinate with a separately retained testifying expert, examine witnesses, or address scientific issues as counsel. A consulting or testifying expert has a different role and must maintain an independent, method-based opinion. Those roles should be defined clearly at the outset.

When can toxicology co-counsel add value?

• Drug- or alcohol-impaired driving: distinguishing analytical detection from impairment and evaluating the specimen, timing, method, and pharmacology.
• Motor-vehicle and personal-injury cases: assessing whether toxicology evidence reliably bears on behavior, reaction time, medical treatment, or causation.
• Overdose and wrongful-death matters: evaluating postmortem findings, redistribution, tolerance, drug interactions, alternative causes, and the limits of concentration-based conclusions.
• Medication-effect cases: analyzing prescribed drugs, metabolites, adverse effects, interactions, and the relationship between laboratory results and clinical evidence.
• Employment and workplace testing: reviewing the difference between screening and confirmation, specimen validity, collection procedures, and the interpretation permitted by the test.
• Challenges to laboratory evidence: identifying missing records, quality-control issues, calibration questions, measurement uncertainty, chain-of-custody gaps, or opinions that extend beyond the validated method.

What records should be reviewed?

A final laboratory report may be only the beginning. Depending on the disputed issue, a meaningful review may require:

• collection records, specimen identifiers, seals, storage conditions, and chain-of-custody documentation;
• screening and confirmation data, chromatograms, mass spectra, batch records, and instrument sequences;
• calibrators, controls, blanks, acceptance criteria, dilution records, and reinjection or repeat-analysis documentation;
• standard operating procedures, method-validation materials, measurement uncertainty, and proficiency-testing information;
• medical, pharmacy, autopsy, scene, driving, or witness evidence needed to place the analytical result in context;
• the opposing expert’s assumptions, calculations, references, and complete opinions.

What a toxicology result can and cannot establish

The defensible interpretation depends on the matrix, collection time, analytical method, case facts, pharmacology, and limitations in the available evidence.

Expert qualifications and reliable methods

California Evidence Code section 720 addresses whether a proposed expert has sufficient special knowledge, skill, experience, training, or education on the subject of the testimony. Federal Rule of Evidence 702 separately focuses on helpful specialized knowledge, sufficient facts or data, reliable principles and methods, and reliable application to the case.

• California Evidence Code section 720
• Current Federal Rules of Evidence

Credentials matter, but the opinion must also fit the issue, rest on sufficient information, and apply reliable methods without overstating what the science can prove.

How the case review proceeds

1. Define the disputed proposition. Identify whether the actual question concerns detection, timing, impairment, causation, laboratory reliability, or another issue.
2. Preserve and obtain the evidence. Request the complete laboratory and contextual record before critical data or specimens become unavailable.
3. Evaluate methods and assumptions. Separate validated analytical findings from interpretive assumptions and unsupported extrapolation.
4. Coordinate the right expertise. Determine whether the case also requires pathology, clinical pharmacology, accident reconstruction, medicine, or another discipline.
5. Present the science clearly. Translate the analysis for motions, deposition, settlement, and trial without sacrificing accuracy.

Forensic toxicology resources for attorneys

• Forensic Toxicology Evidence Library
• Forensic toxicology education and research
• Forensic Toxicology Case Review Checklist
• Toxicology Laboratory Packet Review Guide
• Rule 702 and Forensic Toxicology Expert Testimony
• Forensic toxicology expert-witness services
• Forensic cross-examination samples

Discuss a case involving complex scientific evidence

Okorie Okorocha, J.D., M.S., M.S. works at the intersection of litigation, forensic toxicology, and pharmacology. For a consultation concerning toxicology co-counsel or expert-witness services, call (424) 363-3347 or use the Expert Witness Intake Form.

This page provides general information and does not offer a conclusion about any particular case.