Critical values: Has their time arrived for cytopathology?

The concept that certain test results are critical to patient management and must be communicated to the patient care team as rapidly as possible is well accepted in the discipline of laboratory medicine. The idea of critical values was first addressed by Lundberg, who defined critical values as a pathophysiologic derangement that varies so much from normal that it is life threatening if therapy is not started immediately. This concept resulted in several guidelines issued by organizations, including the American Society of Clinical Pathologists, the Joint Commission on Accreditation of Healthcare Organizations, and the College of American Pathologists (CAP), requiring the institution of critical values policies in laboratory medicine. Subsequent to the dissemination of those regulations, the practice of notifying physicians of these life-threatening laboratory results has become standard practice in laboratory medicine. These critical values are communicated by a laboratory technologist to the physician or nurse responsible for the patient’s care. Precise details regarding which results are deemed critical and how a critical values policy is implemented differ among institutions. Variability exists regarding which analytes should be included in critical value policies, who is eligible to receive critical value reports, and the presence or absence of a written critical value policy. The importance of a laboratory result often depends on the clinical situation. The rapid communication of abnormal, but not lifethreatening, results may represent an unnecessary commitment of laboratory technologist and caregiver time. Lists of critical values have been published, but their implementation and clinical value selection depend on the institution and the type of patient receiving treatment. Laboratories need to carefully select values to ensure a balance between providing appropriate information and not overwhelming clinical staff with information that does not require immediate action. Characteristics of critical values and results include: 1) rapid availability of result, 2) result indicates a life-threatening condition, 3) result should be actionable, and 4) responsible clinician should want to know the result immediately after test completion. Other considerations in developing lists of critical values include identifying who should be called and who should place the call. The precise timeframe for calls also should be addressed in a critical value policy. Several logistical issues impact the success of critical value policies. These include the amount of time required for technologists to return critical values; difficulty in determining who should receive the critical values; and, when the appropriate health care provider cannot be contacted, how to effectively relay the information so that patient care is optimized. The communication of critical values does require greater time expenditure than normal reporting procedures. However, critical values generally represent less than 2% of all laboratory results. The technologist time required to report critical values varies, with reported medians of 6.1