PT in the Pandemic is Unusual Business

May 2021 - Vol.10 No. 5 - Page #20
Category: Proficiency Testing

Q&A with Eugenio H. Zabaleta, PhD
OhioHealth Mansfield Hospital

Medical Lab Management: Back in 2015, we discussed the need for effective policies and procedures for proficiency testing.1 How had your laboratories changed its P&Ps since that time up to the beginning of the pandemic?

Eugenio H. Zabaleta: Despite the turbulent circumstances of the last year, our policies, processes, and procedures regarding proficiency testing remain largely the same as back in 2015. That said, the past year has put significant strain on the “processes” aspect. What had been a generally standardized process in terms of what PT materials were expected and when that would occur throughout the year was substantially upended. So, while we have tried to remain consistent in our policies and procedures for PT, ensuring a broad range of staff perform PT and arranging for consistent delivery of materials and subsequent results has been a challenge in the last 12 to 15 months.

Furthermore, our facility has been moving toward more automated PT processes. This was to be an initiative in 2020, but it has been placed on hold as the pandemic plays out. It is worth noting the impact of staffing issues in both of these cases: PT itself and automating PT. During the pandemic, many health care practitioners of all kinds have retired, taken a leave of absence, or taken other positions (not to mention those directly impacted by COVID-19). This reality, combined with an already anemic market for qualified laboratory technologists and technicians, has made for a challenging environment, indeed.

MLM: What are the primary reasons laboratory leadership should be concerned with PT results in 2021?

Zabaleta: To answer this I need to step back; in the 2015 article I explained that to ensure the laboratory is providing accurate and precise results in all areas, the laboratory must also establish and maintain full control of all the testing processes with a primary operational goal of preventing error. One of the key components of a quality management system (QMS) approach is establishing consistent PT performance over time. Because PT is used as a bellwether of sorts—a canary in the coal mine—laboratories come to rely on that information for not only an assurance that instruments and methodologies are proper and sound, but for peace of mind in general. Thus, disruptions to that consistency are troublesome.

At our institution, PT analytes had traditionally been sent in two to three shipments a year, each containing two to five PT challenges. Over the course of the pandemic, these shipments and the resulting submissions experienced intermittent and various delays and other issues (such as mislabeling or sample damage) that threw off our regular process. We know that positive patient care depends on the known accuracy and reliability of laboratory testing, so we want to consistently probe our systems via interlaboratory comparison and the other benefits of PT. That said, when a laboratory receives an unacceptable PT result, the delays and disruptions to normal processes introduced by the pandemic could also likely slow or otherwise hinder corrective actions.

MLM: How would you characterize the relationship between PT and internal QA activities?

Zabaleta: In order to consistently provide accurate and precise results, the laboratory must maintain full control over all testing processes, including the identification, correction, and prevention of errors (even during a pandemic). Thus, strong PT performance is evidence of a strong QA program. However, no matter how comprehensive your processes, random errors can still occur when processing PT samples.

Keep in mind, quality control (QC) shifts are a common cause of PT failure for chemistry automation, which is why tools such as Levey-Jennings charts and Westgard Rules remain so valuable. These tools can help identify and preempt QC shifts before they impact proficiency or patient care.

MLM: How are the daily QC requirements determined for the equipment you use?

Zabaleta: QC testing is integral to ensuring laboratory processes produce accurate, comprehensive results enabling proper patient care. Thus, good laboratory practices suggest testing normal and abnormal QC samples at least once per day. However, each laboratory should revise and adjust the QC testing schedule according to the following factors:

  • Test volume (low versus high)
  • Availability (24-hour random access versus batch testing on a specific shift)
  • The specific test reagent’s stability (how long the test is stable on the instrument)
  • The priority of testing (STAT versus routine)

Depending on clinical need, as well as the specific test’s analytical performance, it may be wise to run QC samples two or three times per day. In all cases, it is important to take into account manufacturer recommendations.

MLM: Which staff members are responsible for these activities?

Zabaleta: Given that QC testing should be incorporated into all laboratory testing processes, it is crucial that the personnel that perform normal patient testing also carry out QC testing for those same tests. This also extends to PT. However, there is a role for the section head, the lead tech, and the supervisor or manager (depending on the lab structure) in the QC management plan.

Every laboratory should designate a senior staff member to review QC results at least once per month. Keep in mind that QC should serve to monitor the analytical performance of laboratory tests and indicate the presence of any variances in performance. By looking at QC data over weeks or months, performance over time (trending versus random changes) can be determined, and the lab can ascertain whether corrective action is needed, often before the QC actually fails. Thus, as mentioned, most clinical laboratorians continue to utilize the Levey-Jennings Control chart and the various Westgard Rules for QC evaluations.2

MLM: Has the pandemic altered how the laboratory should respond to outlier PT results?

Zabaleta: It certainly should not, but some may argue that over the course of the pandemic, many laboratories have experienced and are still experiencing staffing issues. This is in addition to the logistical challenges already mentioned (delays and irregular timing) and which are now to be expected. Clearly, outlier results introduce more work to gain a clear resolution, but empirically, nothing should change in how those corrective actions are performed based on the pandemic. Ultimately, managing these issues has become more of a human resource challenge than a technical or logistical challenge.

MLM: As we look ahead to the rest of 2021 and beyond, how do you expect PT processes to continue to evolve?

Zabaleta: I think I speak for most laboratorians in this country when I say we are eager to get back to the “boring” pre-COVID-19 processes. Obviously, the more we can regain our standard P&Ps—that is, PT materials delivered regularly and on time, results returned to us in a timely manner, etc—the better. We always want to prove to ourselves that we are providing our clinicians and patients with the high-quality results required for their wellbeing.

MLM: Any final thoughts on how to encourage lab leadership and staff to seek out constant process improvement?

Zabaleta: Yes, I would like to give humble recognition to my fellow laboratorians. Over the last 15 months, I have seen a tremendous sense of collegiality, both professionally and personally. The toll the pandemic has taken on health care practitioners has been profound, but I am proud of my colleagues and peers as they have persisted in the face of great odds to do what they are trained to do in providing quality care. In doing so, we have had to:

  • Implement reagents for SARS-CoV-2 that were not approved by the FDA in the normal way (eg, Emergency Use Authorizations)
  • Navigate multiple reagent shortages for SARS-CoV-2 (and many other conditions)
  • Find ways to maintain our high standards while covering shifts for coworkers caring for friends, family, and themselves
  • Live with the uncertainty of whether we might become sick or transmit the virus to our loved ones

These are in addition to our internal obligations to comply with local, state, and federal regulations. We continue to learn many lessons from this experience, with one being that we will not stop providing the best care for our patients, and we will not sacrifice our QC, QA, and PT programs, come what may. Lab Week may have just passed, but I hope to continue to recognize these amazing efforts well into the future.


  1. Zabaleta EH. Enact Effective P&Ps for Proficiency Testing. MedLabMag. 2015;(4)2:12-13. Available at:
  2. Westgard QC. Westgard Rules and Multirules. Accessed 4.20.21:

Eugenio H. Zabaleta, PhD, is a clinical chemist at OhioHealth Mansfield Hospital in Mansfield, Ohio. He is also a part-time lecturer at Cleveland State University’s graduate clinical chemistry program. He graduated from the Catholic University of Cordoba (Argentina) with a degree in biochemistry and received his PhD in chemistry from the University of Akron. His training in clinical pathology was at the Hospital Provincial San Roque in Cordoba. In Argentina, he was the laboratory medical director at the Clinica del Sol, a clinic devoted to mother and child’s care, with neonatology intensive care service.


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