PT is the most important gauge of a lab’s performance than any other quality indicator.
If your lab’s PT results aren’t consistently 100%, or at least 97% for general chemistries, then there is a problem in your lab. It is important to figure out the problems early, before they get worse and start to affect lab test result quality, and then patient care.

PT failures are not always the fault of the lab. PT providers, such as API, AAB or CAP, are only allowed to grade your results if, your test system combination of reagent and instrument is also being performed by at least 10 or more peer labs. If not, then the PT provider will put you in a larger, more general method group which may not be appropriate for your test system and cause you to fail. This is most common when you are using specialized tests not provided by the manufacturer of your instrument.

For example, a lab was using Kamiya reagent for HsCRP to run on their Beckman Coulter 480. They were consistently failing their PT events. They did not have 10 peers to be compared and graded for methodology of instrument and reagent and so they were consistently failing. Once the lab did a self-evaluation and reviewed the data for their peer group, they passed with 100%. If you still are failing after self-evaluation, there is definitely a problem with your test system and corrective action must be taken.

Accrediting Agencies such as COLA are willing to take self-graded PT to keep a cease testing for PT failures from being implemented.

I hope you learned something for this tip of the month and, as always, please call BLC if you have any questions or need help with PT failures.

Thank you,

Lawrence Fox, B.S. (ASCP)C, NYS CLT.