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Proficiency Testing in Labs

What is Proficiency Testing in Labs?


Proficiency Testing (PT) is a process designed to evaluate a laboratory’s performance, testing accuracy, and overall practices.

Proficiency testing is a means of assessing a lab’s performance under a set of controlled conditions through the analysis of samples provided by an accredited PT provider. Passing the proficiency testing programs is typically required in order for the laboratory to maintain their certifications. 

Typical Proficiency testing includes (1) an evaluation of sample handling protocols, (2) an evaluation of laboratory reporting practices and (3) an evaluation of how accurately the laboratory is able to report the correct analytical results (within specified acceptance limits).

How Do Proficiency Testing Programs Work? 

In a proficiency test, one or more samples are sent to a participating laboratory. The sample, which is provided by an accredited PT provider, contains a known concentration of a given analyte–but that concentration is unknown to the laboratory. The laboratory must complete their testing and reporting process–meeting various standards deemed acceptable by the PT provider.[1]  

If the laboratory fails to perform steps in accordance with the PT provider’s high standards, the laboratory can fail and will thereby need to improve its practices until it’s able to pass the PT program.

Many US states use PT providers that have been accredited by the American Association for Laboratory Accreditation (A2LA) or the American National Standards Institute (ANSI)-American Society for Quality (ASQ) National Accreditation Board/ACLASS. [2

Why is Proficiency Testing Important? 

Proficiency testing is important for ensuring consistency among laboratory performance and for maintaining reliability and high standards. It is an important process for any independent, third-party laboratory to undergo regularly. 

According to the ILAC, some of the potential benefits which may be available laboratories participating in PT programs include:[3

  • Confirming competent performance 
  • Identifying any testing or measurement problems
  • Comparing methods and procedures
  • Improving performance 
  • Educating staff
  • Instilling confidence in staff, management and external users of laboratory services 
  • Comparing operator capabilities 
  • Generating reference materials
  • Determining method precision and accuracy 
  • Satisfying regulators and accreditation bodies
  • Providing laboratories with additional risk management
  • Want More Information about Proficiency Testing?

    Below are some additional resources about proficiency testing programs and providers:

    NEPTP - The NELAC Institute (TNI)
    PT Provider Accreditors - The NELAC Institute (TNI)
    Benefits for Laboratories participating in Proficiency Testing Programs
    Common Proficiency Testing Errors

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    About The Author


    Kate leads operational strategy as COO at Tap Score and SimpleLab. She oversees daily, as well as long-term logistics for tens of thousands of environmental samples across hundreds of certified laboratories. However, she started her environmental testing career by way of scientific blog writing at Tap Score and it continues to be one of her favorite aspects of the business. Outside of Tap Score, Kate loves making homemade pasta, floral arranging, and singing along to Dolly Parton tunes.
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