Utility of iron concentration two to four hours post ingestion in predicting toxicity. Am J Emerg Med 2025 Jan;87:70-73
Date
11/13/2024Pubmed ID
39509998DOI
10.1016/j.ajem.2024.10.042Scopus ID
2-s2.0-85208142108 (requires institutional sign-in at Scopus site) 1 CitationAbstract
INTRODUCTION: Iron products are widely available over the counter and have the potential to cause serious toxicity. Iron concentrations can be used to prognosticate and guide treatment during acute ingestions. Traditionally, a concentration of 350 μg/dL with symptoms, or 500 μg/dL without symptoms, is considered toxic and will likely need treatment to prevent decompensation. It is generally recommended that an iron concentration is obtained at least 4 h after exposure to provide adequate absorption time and avoid falsely low iron concentrations. Despite this, many iron overdoses have concentrations drawn immediately upon patient presentation. The utility of an iron concentration drawn before 4 h in assessing exposure risk is not clear. The purpose of this study is to determine if patients' symptoms and iron concentrations obtained between 2 and 4 h can predict the development of iron concentrations after 4 h.
METHODS: This is a single-center, retrospective study of patient cases with a primary ingestion of oral iron reported to a regional poison center from January 1, 2015 to January 1, 2020. The primary outcome is the incidence of an iron concentration of 350 μg/dL or greater at or beyond 4 h. Secondary outcomes include the incidence of antidotal deferoxamine administration, incidence of iron concentration > 500 μg/dL, incidence of positive findings on abdominal radiography, and time to highest reported iron concentration.
RESULT: A total of 75 patients were included in this study. No patients who developed at most minor symptoms (abdominal discomfort, nausea, vomiting, or diarrhea without evidence of systemic toxicity) and had a 2-4 h concentration ≤ 300 μg/dL symptoms had a subsequent concentration ≥ 350 μg/dL (negative predictive value [NPV] 100 %). Deferoxamine was used to treat five patients, all reached concentrations of > 300 μg/dL 2-4 h post-ingestion.
CONCLUSION: Patients with only minor GI symptoms and an iron concentration of ≤ 300 μg/dL between 2 and 4 h post-ingestion are unlikely to develop further toxicity. In this case series, a concentration of 300 μg/dL or less between 2 and 4 h was the ideal cutoff to predicting subsequent potentially toxic concentrations, with a sensitivity of 100 % and a specificity of 54 %.
Author List
Fox H, Jansen A, Theobald J, Stanton M, Feldman RAuthor
Matthew Stanton PharmD Adjunct Associate Professor in the School of Pharmacy Operations department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdolescentAdult
Aged
Antidotes
Deferoxamine
Drug Overdose
Female
Humans
Iron
Male
Middle Aged
Poison Control Centers
Retrospective Studies
Time Factors
Young Adult
