The establishment and prompt reporting of critical values to patient care providers is one of the crucial requirements of clinical laboratories. Each laboratory is expected to individually establish the thresholds of critical values and periodically update the lists. In this study, we attempted to investigate the status of critical value reporting (CVR) systems in Korean clinical laboratories and develop adequate guidelines based on comparative reviews examining expert consensus. In responses from 11 clinical laboratories, the number of test items with a critical value threshold was 9.4 on average (standard deviation=5.0). Some of the test items, especially ammonia, lactate, and carboxyhemoglobin, lacked critical value thresholds despite having been recommended by expert opinions and guidelines. The upper limit of critical value thresholds showed variability, with glucose showing the largest difference among laboratories (range, 450–700 mg/dL; coefficient of variation=14.7%). When evaluating the appropriateness of establishing critical value for a particular test, it is generally recommended to consider the “actionability” factors, which consist of effectiveness in decreasing mortality, availability of immediate response systems, and inclusion of the decision-making process in the institution’s critical pathway of standard patient care. As for the optimal value of individual thresholds, laboratory managers should review three quantitative markers: the ratio of CVR cases in total reported results, the ratio of confirmed CVR and responses by clinicians in total CVR cases, and the turnaround time of the tests assigned with critical value thresholds.

Keywords: Critical value report, Laboratory critical values, Laboratory management, Quality improvement