METROLOGY IN THE SERVICE OF FORENSICS AND JUSTICE

Lead

In courtrooms, decisions are based on evidence. For evidence to be credible, measurements must be accurate and verifiable. Metrology is therefore an invisible but essential pillar of justice.

Main text

Forensics and the justice system rely on metrology every day. Blood alcohol analysis, examination of fire debris, testing for the presence of drugs, or analysing DNA samples — all of these procedures depend on measurement. If they are not performed with calibrated instruments and reliable methods, the results cannot be accepted in court.

(Visual 1: Sample in a forensic laboratory / Source: CBP Laboratories and Scientific Services (LSS), Springfield, Virginia, Photographer: Donna Burton, Public Domain)

 

For example, in traffic investigations, breathalysers play a crucial role. They are regularly calibrated to ensure that a reading of, for instance, 0.5 ‰ truly corresponds to the actual alcohol level in the breath. An inaccurate device could lead to an unfair verdict — either freeing a guilty person or punishing someone innocent.

(Visual 2: Police breathalyser / Source: Petar Glebov/PIXSELL)

 

In forensic toxicology, measuring the concentration of banned substances in samples (blood, urine, hair) must be exceptionally precise. Laboratory technicians use piston pipettes to accurately dispense reagents and prepare samples; these pipettes must also be regularly calibrated to ensure sample volumes are correctly quantified. An incorrect pipette or imprecise dosing may lead to false negative or false positive results, directly affecting the validity of the evidence.

(Visual 3: Calibration of a piston pipette in an ISO/IEC 17025 accredited calibration laboratory / Source: Sartorius Croatia Libra Elektronik d.o.o.)

 

Forensic laboratories in Croatia performing such analyses are accredited according to HRN EN ISO/IEC 17025, as are the calibration laboratories that calibrate their equipment. This ensures both methodological and metrological validity of results and allows evidence to withstand judicial scrutiny.

 

When a judge delivers a verdict, they may not think about piston pipettes or reference standards — but behind every piece of evidence stand calibrated instruments and experts ensuring the credibility of measurements. Metrology is thus a foundation of trust in the legal system itself.

(Visual 4: The Goddess of Justice always carries a measuring instrument — the scale / Source: ChatGPT)