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Inside the Lab Training and education, Profession, Quality assurance and quality control, Laboratory management

Critical Thinking

At a Glance

  • A sample of inpatient and outpatient lab critical values (CV) reports were examined to see the effects of CV reporting on doctors’ decisions, actions and outcomes
  • Our laboratory has been successful in using a computerized notification system that improves timeliness and avoids communication errors
  • To ensure the best patient care, laboratories must clearly define CVs and adhere to standardized reporting procedures and improve patient outcomes

The classical definition of a laboratory critical value (CV) is any result for which an immediate, life-saving action must be both available and necessary. Clearly, failure to communicate such a result carries a high risk of adverse events including the death of a patient. It is widely recognized that the harmonization of this reporting is key to providing the best possible patient care – and yet there is no standardized method of reporting CVs to ensure maximum effectiveness. In an attempt to remedy this, we and our colleagues recently audited six months’ worth of CVs to evaluate the effectiveness of reporting in relation to clinical decision-making and patient outcomes.

In our study (1), we investigated 200 consecutive inpatient CVs reported by the Department of Laboratory Medicine at the University-Hospital of Padua, Italy. In the same six-month period, we also audited 105 general practitioners (GPs) whose patients were referred to the Department of Laboratory Medicine and reported critical blood clotting rates or potassium levels. We asked doctors – clinicians and residents for inpatients; GPs for outpatients – what actions they undertook after being notified of their patients’ CVs, using a standard set of questions that received a 100 percent response rate. Clinicians also gave us additional information, including their patients’ clinical status, rates of expectation and triggering events for CVs, how they were notified of CVs, and whether or not they agreed with the values delimiting CVs.

As expected, CV notifications – which were unexpected findings in over 40 percent of cases – resulted in treatment changes for about 90 percent of patients in medical wards and 98 percent of those in surgical wards. Clinicians also further evaluated new complications in about 60 and about 70 percent of cases in medical and surgical wards, respectively, took additional patient care steps, and monitored patients’ conditions more closely in over 25 percent of cases. Most surgeons were informed of their patients’ CVs by information technology (IT) notification, whereas clinicians received IT notifications in 75 percent of cases but were also alerted in other ways (clinical records, text messages, reports from on-call doctors, or calls from the laboratory). Outpatients were grouped into two categories – those whose labs showed critical INR (international normalized ratio), and those with critically high potassium levels. For all patients with critical INR, GPs changed or stopped warfarin dosage; subsequently, 24 percent of patients were given an additional INR check and 5 percent were examined in a hospital setting. Hyperkalemic patients were all treated within four hours of physician notification and nine were admitted to the hospital for further treatment. In all instances, it is clear that the laboratory, and its role in CV reporting, is key to ensuring patient safety – and, as a result, the effectiveness of that process should be put under close scrutiny.

Spotlight on CV reporting

It seems rather amazing that the concept of CVs, as George Lundberg originally defined it in 1972 (2), is still being used today. His findings indicated that patients with  abnormally high or low laboratory values could die, or suffer irreparable physical damage, unless treated immediately. It’s been more than 40 years and CV reporting is receiving more focus than ever from both the laboratory scientific community and several regulatory organizations. The body of evidence shows that timely notification of CVs is important for clinicians, and many accreditation agencies agree that CV reporting is one of the most essential tasks for laboratories. Unfortunately there is little information on the relationship between CV notification, doctors’ decisions and improved patient outcomes. Our study aimed to determine whether or not CVs are still crucial in decision-making, but it is important to bear in mind that the testing cycle only serves its purpose if clinicians take action.

We performed a survey at our institution to evaluate the effectiveness of our computerized notification system for reporting CVs. Along with gauging the success of CV notification, we recorded the decisions and behaviors of clinicians after notification, and interviewed them about the importance of the results, as well as any medical actions they undertook or modifications they made to diagnostic and therapeutic approaches. We found that CV notification always leads to a change in patient management and outcomes – principally, the use of alternative drugs to address patients’ health issues. Clinicians also make other calls, including ordering more lab tests and increasing patient monitoring. And wherever possible, with outpatients – especially those suffering critical hyperkalemia as a result of drugs interfering with potassium homeostasis – doctors managed them safely in their homes, sparing them from hospitalization.

Advocating for automated notification

For all telephone calls made from laboratories, the literature indicates an average error rate of 3.5 percent (3). Automated communication improves the timeliness of notification and avoids potential errors. The use of IT is therefore of crucial importance in reducing the communication error rate, and improves the likelihood of reaching the on-call doctor – overall, it represents an efficient method of CV notification that supports effective clinical decision making. At our hospital, a computerized notification system has been implemented with the assistance of the IT department. The system was implemented not only because it meets the requirements of our clinicians and of accrediting bodies, but because we believe it has the potential to improve patient safety and provide context-sensitive reporting, something we consider to be of the highest priority.

Auditing patient outcomes has shown us that effective CV reporting is intrinsic to healthcare excellence – so now we need to get the message out. Laboratories should establish reliable value limits, chosen for true “life-threatening” analytes, and distinguish them from abnormal results. Policies should clearly describe the provider’s responsibilities, for instance identifying the laboratory personnel in charge of CV notifications and the caregivers responsible for receiving those notifications. All of these measures are aimed at optimizing CV reporting, including the acceptable time interval between identification and notification of CVs – a gap that, in our laboratory, is now no more than 40 minutes. Finally, the notification, follow-up and documentation of CVs should all have quality indicators that can be regularly checked to ensure the best possible performance for our patients.

What’s next?

In the future, we plan to conduct studies on the appropriateness of critical cutoff values and design more ways of harmonizing laboratory practices. There’s a lot of work still to be done to make  CV reporting more reliable – we need separate CV lists for neonatal, pediatric and adult care; we need to compare existing policies worldwide to promote cross-border changes and improvements; and we need to develop standard procedures for notifying treating physicians of their patients’ CVs. To that end, we believe our main goals should be to harmonize CVs and the related procedures and practices among laboratories at an International level, as  patient safety plays a key role in the mission of laboratory testing.

If pathologists and other laboratory professionals can rely on clear, universal  CV definitions and notification procedures, we can all improve outcomes for our most vulnerable patient populations.

Top five steps for CV reporting

  1. Define CVs, highlighting the difference between critical values, critical tests and abnormal test results
  2. Identify thresholds using reference evidence sources; cutoff values should reflect true life-threatening situations, according to Lunderberg’s definition
  3. Establish well written CV notification procedures, including: - data validation, avoiding the interference of potential preanalytical errors using automation systems - statement of the acceptable length of reporting, keeping in mind that the timeframe for reporting CVs should guarantee that the responsible physician is notified promptly, so that treatment can be started - communication tools, according to International Accreditation Standards - the identity of who notifies and personnel responsible for receiving results, keeping in mind that the physician is the individual who can really change patient management, while the person who notifies a CV needs to have sufficient clinical judgment to understand whether or not a true medical emergency exists
  4. Track any phase of the CV notification 
  5. Establish procedures to evaluate and monitor the CV notification process and the outcomes.
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  1. E Piva, et al., “Laboratory critical values: automated notification supports effective clinical decision making”, Clin Biochem, 47, 1163–1168 (2014). PMID: 24886769.
  2. GD Lundberg, “When to panic over abnormal values”, MLO Med Lab Obs, 4, 47–54 (1972).
  3. J Barenfanger, et al. ”Improving patient safety by repeating (read-back) telephone reports of critical information”, Am J Clin Pathol, 121, 801–803 (2004). PMID: 15198350.
About the Authors
Elisa Piv

Elisa Piva is a medical doctor working at the Department of Laboratory Medicine of the Padua University School of Medicine, Padova, Italy.

Mario Plebani

Mario Plebani is Professor of Clinical Biochemistry and Clinical Molecular Biology and President of the School of Medicine and Surgery, University of Padua, Italy.

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