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Proficiency Testing - Good Risk Management for the Laboratory

Reprint from Focus On, 1999, Issue 6

Physicians have always been concerned about having an accurate test result to aid in the diagnosis and treatment of their patients. This quality driven mindset lead to the creation of the Medical Laboratory Evaluation (MLE) program by the former American Society of Internal Medicine prior to the legislated need for proficiency test programs. Last year the MLE celebrated 25 years of service to our participants. The program was developed and rolled out to physician office laboratories in 1973. Physician office laboratories recognized the need to develop a mechanism of monitoring the quality of the work performed in their respective laboratories.

In 1967 the Clinical Laboratory Improvement Act (CLIA-67) set guidelines that were applied to large independent laboratories. The stringent regulations established for compliance with this law would have been difficult for the smaller independent physician office laboratories to meet. In 1988 Congress amended the CLIA-67 law to expand it to encompass any entity that performed laboratory testing. This was the birth of Clinical Laboratory Improvement Amendments of 1988 (CLIA-88). The goal of this act was to establish overall quality standards to ensure accuracy, reliability, and timeliness of patient test results regardless of where the test was performed. CLIA further influenced the testing performed in laboratories by mandating that quality controls, quality assurance, and personnel competency would be monitored in all laboratories.

While the physician office laboratories have rigorously attempted to adhere to the CLIA regulations and standards written for all laboratories, this has sometimes become a source of stress for smaller facilities. Facilities without professional laboratorians struggled with unfamiliar requirements and documentation. Regardless of the legislated requirements, physicians have always been concerned about the accuracy of laboratory test results.

In this day of "waived" testing, many CLIA-waived labs are asking themselves, "Do we still need to perform proficiency testing?" Certainly the mere fact that a test has "Waived" status says that proficiency testing is not required under CLIA (check with your state to verify the state's requirement for PT). Therefore we need to look past the "required proficiency testing" and examine the pure rationale behind the comparative laboratory testing we know as PT. Laboratory tests that have been granted waived status by CLIA have fulfilled a specified test protocol in accordance with the Food and Drug Administration (FDA) rules. These tests may be cleared for home use and employ methodologies that are so basic that it is very likely an accurate result will be obtained as long as manufacturer instructions are followed. Furthermore, tests that are included in the CLIA waived category are not likely to cause any harm to the patient if performed improperly. The instructions are written in a simplified format. It may be thought that there is no way a test could be improperly performed. Therefore all patient tests done in this waived test system will always be accurate. This is generally a good premise. Unfortunately, this is not always true.

One possible problem may arise in the area of training. The word of mouth training that is provided by the manufacturer for some of the tests may not be conveyed accurately as one office person trains another. The manufacturer has a package insert of instructions on how the test should be properly performed, but there is no guarantee that each new person will read the package insert.

Another area of concern is the interpretation of the result. This can be a highly subjective process from sample to sample. There is not a test device or system that cannot be compromised by the error of misinterpretation of the result. A person operating in a laboratory without any interlaboratory comparison cannot know that there is a problem with their test system.

Maintaining proficiency testing on both CLIA-waived and non-waived testing contributes equally to your laboratory's quality assurance program. With that in mind, MLE created cost effective modules with only two challenges for waived and non-regulated analytes. Proficiency testing allows laboratories to compare their performance against a group of other laboratories performing the same test or using the same methodology. Matching the results of other laboratories in the same group reinforces a laboratory's confidence in result interpretation, test performance, and test system storage. The most significant benefit of proficiency testing is that the entire test system is evaluated, not just a certain aspect of the test.

A laboratory that does not agree with the other laboratories performing the same test will have an opportunity to investigate their testing and discover a problem with storage of a test system, how it is handled on a daily basis, or any other failure in the test system. For example in the urine dipstick test the strips will deteriorate if allowed to stand uncapped all day in between use. Other tests like erythrocyte sedimentation rate are temperature dependent and proficiency testing will detect problems that can be found through the interlaboratory comparison process. Enrolling your waived tests in proficiency testing keeps your laboratory participating with an ongoing external quality assurance program.

CLIA requirements for Waived Laboratories

According to the CLIA guidelines, laboratories that are performing only waived tests must apply for a Certificate of Waiver. These laboratories will not be routinely inspected. These laboratories may be randomly inspected as part of a compliance investigation to ensure that the laboratories are only performing waived testing. As of 1998, laboratories desiring a Certificate of Waiver were required to pay $150 on a biannual basis.

Quality Assurance

For non-waived laboratories, the CLIA regulations for quality assurance require laboratories to develop, monitor and evaluate the effectiveness of their policies and procedures; identify and correct problems; assure the accurate, reliable and prompt reporting of test results and assure the adequacy and competency of the laboratory staff. The only requirement for waived testing is to follow manufacturer instructions. Regardless of the "required" quality assurance, physicians want to know that the results they are getting are truly accurate.

Proficiency testing provides a convenient external test system to identify any problems with a test performance. By rotating the testing personnel for the proficiency, the laboratory can ensure that all testing personnel are following the manufacturer procedure and are competent in the performance of the test. Without the heavy hand of regulatory requirements for successful testing or proficiency or cessation of test performance, the laboratory can monitor and correct any testing problems independently and proactively through the proficiency test performance.

Performing quality control for waived testing is also part of the quality assurance plan. Many of the earlier waived tests did not have a quality control component to the test. The recent waived tests have quality control either built in on the test device or external quality control packaged with the test. Manual urinalysis dipstick has a recommendation of quality control written on most manufacturer package inserts.


Proficiency testing provides continuing medical education for the laboratory. Enrollment in proficiency testing allows the laboratory to learn from the unknown challenges that are presented. For example, a laboratory is performing waived urine pregnancy tests and assumes that all testing personnel are reading and interpreting the test the same way. However, during a recent proficiency test challenge, the laboratory failed proficiency by reporting positive on a negative sample. The person assigned to report the proficiency for this shipment was over reading the test. This provided an opportunity for retraining of the person in the proper interpretation of the test.

Proficiency testing continues to be the best mechanism for ensuring that laboratory tests are being performed properly. Therefore, the decision to continue proficiency testing on waived laboratory tests is a vital component of the laboratory's quality assurance program. Proficiency testing is good risk management for the laboratory and provides confidence that their results are correct.


CLIA, What You Need to Know About the Waived Testing Category, ACP, 1996.

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