Proficiency Testing (PT)
External quality assessment programs that evaluate a laboratory's testing accuracy by comparing results against peer laboratories and reference values.
What is Proficiency Testing?
- Proficiency Testing
- Proficiency Testing (PT) is an external quality assessment program where laboratories analyze unknown samples and submit their results for comparison against established reference values or peer group consensus. PT programs are mandatory for CLIA-certified laboratories and are essential for demonstrating analytical competency and maintaining accreditation.
How PT Programs Work
Sample Distribution
PT provider sends unknown samples to participating laboratories
Testing
Laboratory analyzes samples using routine methods and personnel
Result Submission
Results submitted to PT provider by specified deadline
Evaluation
Results compared to reference values or peer group mean
Reporting
Laboratory receives performance report with scores
Corrective Action
Failures trigger investigation and corrective action
Major PT Providers
CAP Surveys
College of American Pathologists proficiency testing
ARUP PT
Comprehensive clinical laboratory PT programs
API
American Proficiency Institute programs
AAB PT
American Association of Bioanalysts
EQAS
External Quality Assessment Schemes (international)
WSLH
Wisconsin State Laboratory of Hygiene PT
CLIA PT Requirements
Regulatory Mandate
CLIA requires laboratories to successfully participate in an approved PT program for each regulated analyte. Key requirements include:
- Enrollment in CMS-approved PT program for each specialty
- Three testing events per year minimum
- Five samples per testing event
- Testing under routine conditions with regular staff
- Documentation of all PT testing activities
- Prohibition of inter-laboratory communication about PT samples
Consequences of PT Failure
Unsatisfactory Event
Score below 80% for a single testing event - requires investigation
Unsuccessful Performance
Two consecutive or two of three unsatisfactory events - triggers sanctions
Referral PT
Intentional referral of PT samples - immediate sanctions possible
LIMS PT Management
Modern LIMS systems can track PT sample receipt, testing, and results. Features include PT event scheduling, result entry, automatic comparison to previous events, corrective action tracking, and generation of PT attestation forms for regulatory compliance.