Derivation of outcome-based pediatric critical values

Objectives: There is currently a lack of an outcomesbased definition of critical values for the pediatric population. This has contributed to a highly heterogeneous critical value reporting practice between laboratories. Methods: Anonymized results were extracted from a laboratory information system for 10 biochemistry tests. The probability of high-dependency/intensive care unit admission (as a proxy for adverse outcomes) for each individual laboratory concentration was calculated and adjusted to fit using a polynomial function to model the probability trend. The laboratory value that intersected the 90% probability trend line was considered the critical value threshold. Results: The critical value thresholds for the serum analytes were sodium (mmol/L: <131, >148), potassium (mmol/L: <2.4, >6.4), bicarbonate (mmol/L: <13, >37), chloride (mmol/L: <91, >115), urea (mmol/L: >12), creatinine (μmol/L: >129), glucose (mmol/L: >17.2), total calcium (mmol/L: <1.9), magnesium (mmol/L: <0.6, >1.2), and phosphate (mmol/L: <0.4, >2.6). Conclusions: This study described an approach to derive contemporary pediatric critical value thresholds.