Dear API Abby has been answering your proficiency testing questions online throughout 2026. Now, the Abbys are pleased to share highlights from some of the most popular questions and answers. The Abbys may be found at the American Proficiency Institute (API), a global leader in proficiency testing programs. Known for its constant innovation in the field, API offers technical expertise and checklists to help its laboratory customers become more proficient. Now let’s get to your favorite questions!

Dear API Abby:

I received a notice from my accreditation agency that I am not enrolled in all the proficiency testing I need. I am enrolled for all the tests we perform in the lab. Why would they be asking me to enroll in more?

—Dazed and Confused

Dear Dazed:

If you are confident about your PT enrollment, I can see why a notice about missing PT would be confusing. Some regulatory agencies keep a list of tests you perform and verify your PT enrollment against that list before the year starts. The main goal is to prevent you from missing required PT, but it is also a helpful quality control check of both organizations’ records.

The most common reason for receiving such a notice is that your laboratory test menu has changed slightly, and the regulatory agency does not know it. Maybe you switched to a waived method and changed your PT enrollment to only two samples per event. Until you notify your regulatory agency, they would still expect you to enroll in five samples per event. In this case, telling them you now use a waived method would reduce your PT requirements and likely resolve the matter. Notifying your regulatory agency any time you make a change will help to ensure you are meeting your requirements. Don’t be afraid to contact them. They are your partners in laboratory quality and want to help! 

Dear API Abby:

We failed two of our last three proficiency events for chloride. This has never happened to us before and we are at a loss for what to do. We were notified that we need to perform reinstatement testing to be able to continue reporting this analyte for patients. What is reinstatement testing and when can I start testing again?

—Is All Lost?

Dear Lost:

Not all those whose proficiency results wander are lost! There are routes you can take to bring you back to the required path. Reinstatement testing is when two graded events are performed successfully on blind samples. It is used to show your regulator that you have corrected the cause of your two failed events. Reinstatement may be taken as regular PT events or as off-schedule testing from any HHS-approved PT provider. You may start testing patients again after your regulator reviews your corrective action and reinstatement scores and approves your request to resume patient testing.

However, since you received a notification, you may also be required to wait for six months before resuming testing. Read your notification carefully for the details that apply to your situation. A cease testing sanction is not always issued; it depends on your PT history and other factors. For next time, note that laboratories with two failed events who contact their regulator before a cease testing is issued can often avoid the six-month pause in patient testing and potential suspension of Medicare and Medicaid reimbursement.

Before performing your two reinstatement events, ensure you have identified and corrected the root cause of the unsuccessful performance. To confirm that your corrective action was successful, retest your original samples, or get “troubleshooting” samples from your PT provider. Then, reach out to your PT provider or others, if needed, about how soon you can test two sets of blind samples. Usually turnaround is shorter for off-schedule samples than for a regular PT event. Any reinstatement samples should be tested and documented just like PT samples, and you will receive a formal evaluation.

Keep detailed documentation along the way, and you’ll soon be back on track!

Dear API Abby:

I do my best to submit successful proficiency testing results, but I often seem to get dinged due to clerical errors. Is this a common issue among laboratories? What steps can I take to reduce these errors and improve my performance?

—Clerically Yours

Dear Clerically Yours:

You are not alone! Clerical errors remain one of the most common reasons laboratories receive unsatisfactory proficiency testing scores. Studies have shown that a substantial proportion of proficiency testing failures stem from transcription or reporting errors, rather than analytical problems with the testing. For example, one laboratory study found that 44% of unacceptable proficiency testing submissions were caused by clerical errors.¹

The good news is that these errors are highly preventable. Make it a habit to double check your results before submitting them by carefully reviewing all written words, numbers, units, and methods. You may be surprised by how often a quick review uncovers a clerical error that would have otherwise gone unnoticed. This practice is especially important if your laboratory transcribes patient results into a medical record. After all, if you were the patient receiving those results, you would want the information reported accurately and correctly.

Another effective strategy is to have a second person review the results prior to submission. Ask them to pay careful attention to decimal places, instrument and methods selection, transcription accuracy, and confirming the unit of measure the result is reported in. 

If you’re lucky, your proficiency testing provider offers a process that eliminates the need for manual entry of data. Using this approach, your laboratory would register its proficiency testing samples through its own laboratory information system. From there, your laboratory can order and complete the testing, export the proficiency testing data, and upload it directly to the proficiency testing provider, where the results are evaluated. Not only is manual entry eliminated, but your laboratory will save time and resources. Ask your proficiency testing provider if they have such a system — and if it is offered free-of-charge.

Dear API Abby:

My laboratory is trying to figure out how best to learn from our proficiency testing failures. Is it acceptable troubleshooting to repeat the proficiency testing samples?

—Baby One More Time

Dear Baby:

When investigating a proficiency testing failure, you should focus on identifying the root cause rather than simply correcting the immediate problem. Chances are, if the source of the error is not addressed, the problem will resurface later. Start by comparing the tested results with the reported results to determine whether a clerical or transcription error occurred. If the failure was due to a reporting mistake, you'll need to determine how and where the error occurred and whether additional safeguards should be implemented.

It is also important to evaluate any human factors that may have contributed to the failure. Verify that testing personnel followed the laboratory's standard operating procedures, used the correct methodology, and complied with all proficiency testing provider instructions for testing and reporting results.

Next, review all quality control data generated before, during, and after the proficiency testing event to determine whether there was any indication of test system instability or variability. Examine instrument maintenance logs, calibration records, reagent lot numbers and expiration dates, and any recent changes to testing procedures. It is also valuable to consider whether specimen handling, sample preparation, environmental conditions, workflow interruptions, or other unusual circumstances may have affected the results.

Once the root cause has been identified, your laboratory should develop a corrective action plan that directly addresses the issue. This may include staff retraining, procedure revisions, additional quality checks, instrument maintenance, or changes to documentation and reporting processes.

Finally, assess whether the root cause could have affected patient testing and determine whether any follow-up actions are necessary. A thorough, well-documented investigation not only helps prevent future proficiency testing failures but also strengthens the overall quality and reliability of your laboratory's testing program.

REFERENCE

1. Xu P, Wu F, Lewis C. A-180 Counting CAP deficiency Caused by Clerical errors: a regional study. Clin Chem. 2025;71(Supplement_1). doi:10.1093/clinchem/hvaf086.174.