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Serum free cortisol index, free cortisol, and total cortisol in critically ill children

Preamrudee Poomthavorn1, Rojjanee Lertbunrian, Aroonwan Preutthipan

  • 1Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Rama 6 Road, Bangkok, 10400, Thailand. rapptv@mahidol.ac.th

Intensive Care Medicine
|April 9, 2009
PubMed

Insights

In critically ill children, free cortisol index (FCI) and calculated free cortisol (cFC) better assess adrenal function than total cortisol (TC). These measures provide a more accurate evaluation of adrenal insufficiency (AI) in critical illness.

Area of Science:

  • Pediatric Endocrinology
  • Critical Care Medicine
  • Hormone Assays

Background:

  • Serum total cortisol (TC) may be unreliable in critical illness due to altered cortisol-binding globulin (CBG).
  • Accurate assessment of adrenal function is crucial in critically ill pediatric patients.

Purpose of the Study:

  • To evaluate adrenal function in critically ill children using free cortisol index (FCI) and calculated free cortisol (cFC).
  • To compare the utility of FCI and cFC with TC levels in assessing adrenal function.

Main Methods:

  • Inclusion of 32 critically ill children and 36 healthy controls.
  • Administration of a 1 microg cosyntropin test to all participants.
  • Measurement of basal and peak total cortisol (TC), cortisol-binding globulin (CBG), FCI, and cFC.

Main Results:

  • Critically ill children exhibited significantly higher basal and peak TC, FCI, and cFC compared to controls.
  • FCI and cFC demonstrated a greater degree of elevation in patients versus controls relative to TC.
  • Utilizing FCI or cFC for diagnosing adrenal insufficiency (AI) decreased AI diagnosis frequency by 50%.

Conclusions:

  • Free cortisol index (FCI) and calculated free cortisol (cFC) offer a more accurate reflection of dynamic adrenal function in critically ill children.
  • These advanced measures improve the diagnostic accuracy for adrenal insufficiency in pediatric critical care.
Abstract

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