Beyond the Report: 5 Questions Attorneys Should Ask About Toxicology Evidence

A toxicology report may be only a few pages long.

The questions behind it can fill an entire case.

When attorneys receive a forensic toxicology report, attention naturally goes to the substances detected and the concentrations reported.

But those findings are only the beginning of the scientific evaluation.

Here are 5 questions I believe are important when reviewing toxicology evidence:

1. WHAT SPECIMEN WAS TESTED?

Blood, urine, vitreous humor, oral fluid, hair, and tissue provide different types of information.

A positive result in urine, for example, may establish prior exposure but it does not necessarily establish impairment at a particular time.

2. WAS THE RESULT SCREENING OR CONFIRMATORY?

Not all positive findings carry the same analytical weight.

Understanding the methodology including whether a result was presumptive, confirmed, qualitative, or quantitative is essential before drawing conclusions from it.

3. WHAT DOES THE REPORTED CONCENTRATION ACTUALLY MEAN?

A concentration should not automatically be characterized as therapeutic, toxic, fatal, or impairing without appropriate context.

Interpretation may depend on tolerance, specimen source, postmortem changes, medical history, timing, and other factors.

4. WHAT OTHER SUBSTANCES WERE PRESENT?

Drug interactions matter.

Alcohol, prescription medications, illicit substances, over-the-counter medications, and other compounds may produce additive or synergistic effects or complicate an otherwise straightforward interpretation.

5. WHAT CAN THE TOXICOLOGY SCIENTIFICALLY ESTABLISH?

Perhaps the most important question.

Does the evidence establish:

Exposure?
Recent use?
Impairment?
Toxicity?
Contribution to death?
Cause of death?

These are not interchangeable conclusions.

A detected drug does not automatically establish impairment.

A measurable concentration does not automatically establish causation.

And a toxicology result should not be interpreted independently of the medical, investigative, analytical, and in postmortem cases, autopsy evidence.

Forensic toxicology is not simply about asking:

“What drugs were found?”

It is about asking:

“What conclusions can the scientific evidence actually support?”

That distinction can be critical in criminal, civil, administrative, and wrongful-death litigation.