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Abstract: TH-PO527

Prediction of Ionized Hypocalcemia by Anion Gap and Its Components in Children Admitted to the Intensive Care Unit: A Retrospective Cohort Study

Session Information

  • Pediatric Nephrology - I
    November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

  • 1900 Pediatric Nephrology


  • Alhaj, Jmal, SUNY Downstate Health Sciences University, New York City, New York, United States
  • Mongia, Anil K., SUNY Downstate Health Sciences University, New York City, New York, United States
  • Bamgbola, Oluwatoyin F., SUNY Downstate Health Sciences University, New York City, New York, United States

The diagnosis of ionized hypocalcemia based on total serum calcium can be misleading. Correction of total calcium for hypoalbuminemia may be erroneous because calcium binds to other anions outside of the serum albumin. In this study, we tested the hypothesis that a correction of total serum calcium for anion gap and its components would improve the accuracy of a non-invasive diagnosis of ionized hypocalcemia in pediatric patients admitted to the ICU.


This is a retrospective study of patients aged 1 month to 21 years who were admitted to PICU at SUNY Downstate Medical Center between 2016-2020. All patients who had measurements of basic metabolic panel and blood gas analysis respectively taken within 60 minutes of each other were included. Logistic regression analysis for the prediction of ionized hypocalcemia using either the anion gap (AG model), its ion components (Na, Cl, and CO2; ion model), total serum calcium, and serum albumin as independent variables were performed.


Compared with the AG model, the ion model was a better predictor of ionized hypocalcemia. The value of area-under-the-curve (ROC) was 0.85 (p < 0.005) for AG model and 0.9 (p < 0.005) for the ion model (Figure 1). Both parameters were more predictive of ionized hypocalcemia than the albumin-adjusted calcium method with the value of the ROC of only 0.8 (p < 0.05), Figure-1.


A correction of the total serum calcium for the anion gap and its components [sodium, chloride, and CO2] respectively improved the ability to diagnose ionized hypocalcemia non-invasively in pediatric patients admitted to ICU.