American Association for Clinical Chemistry
Better health through laboratory medicine
June 2009 Clinical Laboratory News: Critical Values in an Adult Population


June 2009: Volume 35, Number 6

AACC’s Expert Access
Critical Values in an Adult Population

Each month, AACC’s Expert Access Live Online Program features a different hot topic. Visit AACC’s website for more information and an archive of past presentations.

The following is an excerpt from the April 2009 presentation by Corinne Fantz, PhD, assistant professor of pathology and laboratory medicine at Emory University School of Medicine, Atlanta, Ga. 



Q: Should elevated troponin levels be called a critical result, and if so, at what level? Any detectable level of troponin is significant; but at what point is it critical?
A: My recommendation is to not have an absolute critical value cutoff established for troponin. Perhaps delta troponins should constitute a critical value; we are investigating changing to this. But an absolute cutoff, I don’t support at this time. Any detectable level of troponin is significant; but at what point is it critical? The critical nature of the result depends on the patient. I agree any detectable level is significant, but this value should be reviewed with respect to that individual patient. This one is not black and white. For example: Patient A. Presenting to the ED, first troponin undetectable, second troponin 2 hours later above the upper limit of normal. Patient B. First troponin above the upper limit of normal and second value 2 hours later also above the upper limit of normal but unchanged from the first.

Q: We have had BUN at > 70 mg/dL on our critical call list for many years. Our only exceptions are the renal and intensive care services. We don’t make exceptions for the first reported value. Maybe the fact that we have a major transplant program factors into BUN being on our list. Do you have any thoughts or suggestions as to how we should proceed to change this long-standing test on our critical call list?
A: We do not currently have BUN on our critical value list. You could use an approach similar to ours. Contact other transplant centers of similar size as well as other hospitals in your area locally. Find out what they are using for critical BUN (if any) and report these findings to your pathologist/or director who can speak on behalf of the laboratory at the next medical practice committee to see if you can get the change pushed through. The published surveys can be put in there as well. Bottom line: Use all available data and communicate your finding to those who can help you change.

Q: Are there any best practices for communicating critical values to healthcare providers that are outside of traditional phone calls? During dayshift, calling nursing staff works fairly well, but breaks down completely during night shift when many units do not have dedicated staff to handle the phones.
A: Staffing shortages are a concern. My suggestion is to document what you are finding and share this information with nursing leadership, see if there are ways to work together to met your targets. I would recommend that you clearly define your target calling goals (95% in 15 minutes or less, for example) and show (with data) that you meet this well during the day shift but at night you are having difficulty. There should always be some lead person that may be able to take those results. You want to work with the leadership to develop a way that will ensure patients get the same quality of care day or night.

Q: I noticed you do not have INR listed as a critical value. Do you have a notification protocol for highly elevated INR?
A: We actually do have a critical INR defined, but it is not one of the most common eight test results that we call. Our value is an INR of >5.0.

Q: Do you support having multiple critical values? For example one for critical care areas, and a different one for general medical floors. Or for selected diagnosis, such as renal failure?
A: If your LIS can support this activity it may be a good idea in certain situations. We have one critical value/critical test list. What I want to ensure is that patients are getting the same quality care at each location. In certain situations what is “life-threatening” for one group may not be for all others and vice versa. You need to work with medical staff to understand the processes in “unique” locations and determine if the calls or lack of calls are courtesy versus real clinical need.

The opinions and information are the sole responsibility of the presenter. AACC reviews the presentations for overall appropriateness, but this should not be construed as an endorsement by the association or its employees of the opinions and information offered here.

Supported in part by an education grant from Siemens Healthcare Diagnostics.

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