Critical Values

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Slide 1: Title Slide

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In this presentation, I will review important concepts related to critical values, namely how to define critical values, how to manage critical values in terms of lab processes and processes for reliable reporting and follow-up.

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Lundberg first described the concept of a critical value in 1972. He said: “A laboratory test result that represents a pathophysiologic state at such variance with normal as to be life-threatening unless something is done promptly and for which some corrective action could be taken.”

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The government and those deemed status agencies are particularly interested in knowing how reliably this information is communicated. While the physician is ordering the test, they are also taking care of a number of patients with more often than not, a suboptimal tracking system. It is often the unexpected result that goes unnoticed.

Since CLIA 88, laboratories have had to have a written procedure for critical value result reporting. TJC has required in their NPSGs that there be documentation of receiving the result by reading back and verifying the information. Communication of the results needs to include the turn around times to reach the licensed provider as well as evidence of an ongoing monitor of this process. The College of American Pathologists has similar requirements in their checklist, including the requirements for a procedure, documentation, read back and turn around times.

The laboratory with access to these data in real time plays a key role in alerting the caregiver to a potential life-threatening situation. However, with the number of handoffs and complexity of our systems, it has been a challenge for hospitals to develop a reliable communication plan that consistently documents a responsible party for receiving the result and impacting the care of the patient.

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Given the complexity of individual hospital systems and practices, regulatory agencies have allowed for autonomy when it comes to defining their critical value lists. However, hospitals should be cautioned not to deviate too far from the standard of care. Attempting to define what is considered critical can therefore be somewhat of a challenge for hospitals and laboratories. Most of the published literature on critical values is in the form of hospital surveys. Many of these surveys mix centers of different size and complexity of patients. Additionally, these surveys also do not address differences in instrumentation or specimen integrity or quality. There are, however, a small number of institutional case studies that may help decrease some of the bias in the comparison, but again, with the caveat of not knowing which instrumentation is used.

There is very little in the way of evidence for setting absolute limits for particular analytes. What these studies do offer however, are valuable glimpses into the impact on patient care, but this comes with some limitations. No system is going to allow a study seeing how extreme one can push the cutoff limits before there is a significant increase in deaths. Rather, these studies have focused on current practices; for example, studying outcomes of patients with results above and below a particular cutoff. These studies suffer from inherent bias if physicians are already used to being called at a certain level. It is difficult to discern if a patient is treated more or less aggressively based on receiving a call versus an arbitrary cutoff for the study design.

Because the regulators allow hospitals the freedom to define their critical value lists, many laboratories consult the physician practice group. Representing a diverse group of physicians with unique perspectives, this group has the clinical experience and understands the resources and limitations of the system. They can also comment on specific clinical service needs (for example: emergency medicine, transplant, or oncology). The value in this approach is that a critical value list developed with a medical practice committee is one of the clinician’s perspective.

Combining all of the available resources including local and national peer comparisons is likely to aid the hospital in defining appropriate critical values (i.e. ones that could be considered standard of care) and limiting the calls to those that will truly impact care.

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Defining what constitutes a critical result is a challenge and laboratories often feel like many of the results they are calling are not immediately life threatening. While the results they are calling about may not be immediately life threatening or critical, they may be considered urgent, or significant but non-urgent, meaning that without clinical action there will likely be morbidity or mortality associated with that finding. Some systems have had success in adopting a tier system of colored alerts (for example: Red, Orange, Yellow) that allow laboratories and hospitals to further define how significant the test result is in terms of when they report. Although the time limit for acceptable notification may differ from institution to institution, this approach may ensure more comprehensive notification of clinically significant test results and perhaps, better utilization of the laboratory’s resources. In this example, any test labeled as Red would require immediate notification while urgent results (Orange tier) would allow reporting up to 12 hours, and significant, but non-urgent (Yellow results) may be called within 2 weeks.

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How laboratories manage critical and significant results can impact the care of their patients. Simply labeling a test as critical can have an impact on turn around time compared to normal results. In this example, our laboratory looked at noncritical versus critical troponins. The mean time to report a noncritical troponin was 3 minutes from the time the result was ready of the instrument until it was released in the LIS, while the critical troponin mean time to release was 31 minutes. Many chemistry and hematology analyzers in use today are coupled with some form of middleware or rules based checking embedded in the laboratory information system that can be designed to stop the resulting of critical values for repeat testing and/or calling the clinician, so the user should be aware of the limitations of the system and work to improve the turn around times of the exceptions.

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There is great variability among laboratories with respect to practices for repeating critical results before resulting. A recent Q-probes study showed that 61% of laboratories surveyed were repeating chemistry critical values and another 53% were repeating hematology critical results. Today’s instruments have improved precision and linearity compared to instruments we used in the 1970’s when we first began the practice of calling critical values. Chima and colleagues at Kaiser Foundation Hospital in San Francisco retired their policy of repeating critical results, and they were able to improve the lab’s efficiency and turnaround time. A six-month monitoring period showed no reportable patient care issues as a result of implementing the change. Laboratories should consider the value of repeating the test versus having the result available faster for the clinical team to take action.

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From a litigation standpoint, communication errors dominate medical malpractice claims. Operationally, communicating the critical results from a laboratory perspective is as much driven by the significance of the alert (as we alluded to earlier: Red, Orange, Yellow) as it is by the setting. According to a survey (Howanitz PJ, Steindel SJ, Heard NV. Laboratory critical values policies and procedures: a College of American Pathologists Q-Probes study in 623 institutions. Arch Pathol Lab Med 2002; 126:663–9), the time it takes to contact a provider is faster for an inpatient provider than it is for an outpatient provider. The survey reported 6.1 min for Inpatient and 13.7 min for Outpatient. The good news is there are far fewer outpatient criticals, but the bad news is they are more likely to be unexpected and if there is difficulty reaching a provider, depending on the reliability of the provider result tracking system, the test result may go unnoticed. Follow-up in either case, inpatient or outpatient, is crucial to provide care that can positively impact the patient’s outcome. This slide demonstrates one lab’s process for communicating a critical test result and the escalation plan if they are unsuccessful. The protocol needs to be clear with respect to whom to call, when to call, and how to
escalate if a provider is unavailable. Laboratories should recognize that simply making a call to a licensed provider isn’t necessarily ensuring that the loop is closed and that the patient will be treated accordingly. For this reason, laboratories should assist the clinical areas with monitoring how effective the entire communication plan is at closing the loop. For example, laboratories can periodically send all the clinical areas the previous day’s critical results as a way to audit success of the process. This can be especially helpful in reviewing textual results that may be difficult to flag electronically as critical.

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Laboratories must recognize they are part of a larger system and should not optimize their own processes at the expense of the other parts and the larger whole. There is a balance between helping to alert someone to a life threatening situation vs. slowing down care with increased documentation and high background of unnecessary calling. If the laboratory is calling all critical results, there may be an opportunity to decrease call volume by conferring with the clinical staff to determine if it is necessary to call all critical values or whether or not some of them could be called only on the first occurrence or once a week. The system needs to make sure the list and frequency of alerts is appropriate for the practice.

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Following the mean time to call may not be helpful for setting targets & reporting data on critical values. What you really want to know is how many meet or exceed the target & how many did not meet the target. The ones that did not meet the target can become the lab’s next performance improvement project. For example, if you set your target at 15 minutes and use only the mean, then you may be satisfied that you met your goal. However, if you zoom in on the graph, you can see that a large number (7%) did not meet the goal of 15 minutes. A better way of stating the goal would be: Our goal is to call 95% of our critical results in less than or equal to 15 minutes.

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As the health care record becomes more sophisticated, there may be a real possibility for the health information to be aggregated in such a way as to detect negative trends and such that clinicians may be alerted to a significant trend before a patient becomes critical. Consider rules in the electronic record scanning for undesirable trends on discharge. An absolute cutoff may not be critical, but trending data over time may clearly show a smoldering process that can be responded to immediately rather than waiting for the patient to be readmitted. Post discharge follow-up is another concern for patients, laboratories and providers. Systems should be in place to track results and communicate to patients and providers should there be a critical result returned post discharge. Many electronic medical records have result management functionality which is built to receive and to document provider acknowledgement of certain test results. Consider a situation where a result was electronically sent to the wrong provider who did not acknowledge the result within the defined limit. If test results are not acknowledged by the provider after a predetermined interval, an escalation process to ensure result delivery and acknowledgement can begin. With a system like this, laboratories may benefit by eliminating the current necessity to call all Yellow (significant, but non-urgent) alerts by choosing to track and document the non-urgent results with their result management feature.

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In summary, critical value protocols lack uniform critical value lists. Regulatory agencies have allowed for autonomy and this is consistent with the individual practice needs of different hospitals, but laboratories should be able to gather enough data locally or nationally for comparison and determine what is reasonable for their system while maintaining a standard of care. Building reliable communication systems is the key to the success of any critical value protocol. With the goal to make them as reliable and robust as possible, systems can improve critical value reporting processes by automating and streamlining notifications, learning from past mistakes, increasing standardization, decreasing handoffs, setting meaningful targets, and auditing records to look for weaknesses and inadequate documentation.