PT Primer for Waived Testing

Introduction

Waived testing has the potential to impact patient care.

Proficiency Testing (PT) is not a federal requirement for waived testing, but please consider enrolling as a Good Laboratory Practice that shows your commitment to providing accurate results for your patients. PT serves as an external check to verify the accuracy of your laboratory’s test results by providing unknown specimens for you to test. It is an important aspect of a laboratory’s overall quality assurance. Your lab can gain significant information about your performance when you participate in a Proficiency Testing program.

When you enroll in a PT program, select modules that are designed for waived testing. The PT program customer service representatives can help you make the best selections that are compatible with the tests you perform.

Your lab will receive PT samples periodically over the year, according to the PT program’s published shipping schedule. Be sure to note your program’s shipping dates. If your samples to do not arrive when expected, contact your provider.

Testing PT Samples

Check the PT samples as soon as they arrive in your lab and read the instructions. Notify the PT program right away if samples are missing or damaged, and store them as directed until you test them. Make note of the cut-off date to submit your results so that you will be sure to submit your PT results on time.

It is important to follow the exact step-by-step instructions for handling and testing of the PT samples.  All PT samples must be treated in the same manner as patient samples. That means no repeat testing or averaging of results, unless that is what your lab normally does for patient tests. PT is not a meaningful quality check of your routine testing if you perform it differently than you perform patient tests on a normal work day. Over the year, rotate testing of the PT samples among all individuals who perform patient testing so that everyone that performs waived tests gets a turn at performing the PT.

There must not be any communication with any other laboratory about PT samples or PT results prior to the cut-off date for submitting the results. Do not even compare your results with another location of the same practice.

Proficiency Testing samples must not be sent to any other laboratory EVER, even if your laboratory is temporarily unable to test them.  Promptly notify the PT provider if your lab cannot test the PT samples so that your lab will not receive an unacceptable score. Do not send PT samples to another laboratory, even if under certain circumstances your laboratory normally sends out patient samples. If your laboratory would normally send the sample to another laboratory, this should be documented on the result submission form.

PT Review

When all of the results are received by the Proficiency Testing program, they are grouped, analyzed, graded and then reported back to the participating laboratories.

When your lab’s results are received, they should be promptly reviewed and evaluated by the Laboratory Director or a qualified staff member. The results of the PT should be shared with the testing personnel. All unacceptable PT results must be investigated to determine the problem and if patient results may also not be accurate. When problems are found, it is important to quickly take steps to correct them, such as remedial training. It is recommended that the Laboratory Director review/initial/date all investigations of unacceptable PT results.

All ungraded results should be self-evaluated. These situations occur when:

  • A 0% score is given because the laboratory did not participate in the event or did not submit the results to the PT program on time.
  • A 100% score is given because the result could not be graded due to lack of a comparison group or lack of consensus among participating laboratories.

Troubleshooting

Keep in mind that unacceptable PT performance may be an indication of problems with instrumentation, personnel training, or quality control procedures. It is a good idea to retain and properly store remaining PT samples so they may be retested if troubleshooting becomes necessary.

If your laboratory’s result is outside the range of “acceptable values,” then there is a problem that must be identified and corrected. Use the following questions as a guide to identifying where the problem lies:

1. What is the scope of this problem?

  • Is a single or are several tests affected?
  • Is a single or more than one sample affected?
  • Is a single or more than one instrument affected?
  • Are all result ranges or just a certain range of test results affected?

Narrowing the scope of the problem may help identify where corrective action is needed.

2. Can you identify any clerical errors? This is a common problem.

  • Is information copied onto the answer sheet correctly?
  • Are numbers reversed on the answer sheet? Was the proper method code used?
  • Did the PT program enter your answer correctly?

If clerical errors are the cause of the problems, document your findings and take corrective action to avoid these types of errors in the future. If the PT program made a mistake, contact them immediately to have the error corrected. If this was not the source of the problem, continue:

3. Can you identify any testing errors or instrument failures?

  • Was Quality Control acceptable at time of testing event?
  • Was there a mix-up of the samples? A specimen preparation error?
  • Are calibrations up to date? Has maintenance been performed appropriately?
  • Have there been changes in the Quality Control results since the testing event?
  • Were all reagents, controls, and samples stored properly and not expired?

If any of these questions identifies a possible problem, take corrective action, document and proceed to verify your corrective actions have worked by using stored PT samples, requesting additional PT samples or using another form of external validation. Remember to document all corrective actions and retain this in your laboratory’s records.

Documentation

All documentation of how the Proficiency Testing samples were handled and tested should be kept. This will help if any questions arise when you get your results back. Keep the instruction booklet provided with the samples, all work sheets, instrument tapes and logs related to the samples you tested, and copies of the result submission forms.

Helpful Hints for Proficiency Testing

Below are some hints to help you obtain the best proficiency testing results:

  • Refer to the shipping schedule provided by your PT program. If you do not receive your PT samples when expected, alert them within the allotted time. They will send a replacement shipment promptly if notified in time.
  • Contact the PT program promptly if PT samples are received damaged. You may be able to receive a replacement.
  • Strictly follow the PT provider’s storage requirements prior to testing PT samples.
  • Test PT samples within the time frame provided by the PT provider; promptly report results.
  • Avoid clerical errors when completing PT answer sheets. Be sure to enter the correct result in the correct place on the answer form. Have another staff person double check the answer sheet before sending it to your PT provider.
  • Identify the correct instrument or method code so you are graded among the appropriate comparison group. If you are not sure which method code to use, telephone your PT program’s Customer Service for help.
  • If you do not perform a particular test listed on the answer form, use the correct code to indicate Test Not Performed. Answer forms left blank are often counted as a failure to participate and could reflect negatively on your score.
  • Make and retain copies of all answer forms prior to submitting your results to your PT provider.
  • Be sure that the attestation form is signed.
  • Carefully review your result reports when you get them back, follow up on reasons for PT failures, and correct them.
  • Document all corrective actions in your lab’s records.
  • If you cannot perform PT for a test due to circumstances beyond your control, notify your PT provider in writing. List the test(s) affected and give the reason. This will prevent your laboratory from receiving a failing score for the test.