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]