Proficiency Test (PT)
Definition
An external blind trial in which a laboratory receives samples of known (but concealed) identity and is evaluated on whether its results match the known answers. Distinguishes from internal quality control, which is run by the same laboratory.
- Type
- External blind trial
- Distinguishes from
- Internal quality control
- Sample identity
- Concealed from the analyst
- Purpose
- Independent competence verification
Common questions
Why does a proficiency test need to be blind to be meaningful?+
If the analyst knew the true identity or expected result of the sample in advance, the test would only confirm they can produce the right answer when told what it is. Blinding forces the laboratory to apply its normal methods and judgement exactly as it would on a genuine unknown casework sample.
How does a failed proficiency test affect a laboratory's accreditation?+
Accreditation bodies typically require the laboratory to investigate the root cause, implement corrective action, and may require a retest or restrict the scope of accreditation for the affected method until the issue is resolved.
Related terms
- Accreditation Body
- A national or regional organisation that assesses laboratories against ISO/IEC 17025 and grants accreditation. Examples include UKAS (United Kingdom Accreditation Service), NIST-associated...
- Blank Control
- A sample known to contain none of the target material, processed in parallel with real exhibits to detect laboratory contamination. A positive...
- ISO 17025
- International standard for the general requirements for the competence of testing and calibration laboratories. Covers management system requirements (document control, internal audits,...
- Method Validation
- The process of demonstrating that an analytical method does what it claims: that it correctly identifies the target analyte, at what sensitivity,...
- Reference Collection
- A curated library of verified specimens from known species, subspecies, and geographic populations used as comparators in forensic identification. The depth and...