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Calcium levulinate medication. A pitfall in the diagnosis of organic acidurias

Insights

Calcium levulinate administration to children resulted in excretion of 4-oxopentanoic and 4-hydroxypentanoic acids. These metabolites may be misidentified as markers for beta-ketothiolase deficiency in certain diagnostic tests.

Area of Science:

  • Biochemistry
  • Pediatric Medicine
  • Metabolic Disorders

Background:

  • Beta-ketothiolase deficiency is a rare genetic disorder affecting amino acid metabolism.
  • Accurate diagnosis relies on identifying specific organic acids in biological samples.
  • Gas chromatography-mass spectrometry (GC-MS) is a common analytical technique for detecting these acids.

Purpose of the Study:

  • To investigate the metabolic fate of intravenously administered calcium levulinate in children.
  • To determine if calcium levulinate administration produces metabolites that could be confused with markers of beta-ketothiolase deficiency.
  • To inform diagnostic interpretations in pediatric metabolic screening.

Main Methods:

  • Five children received intravenous calcium levulinate (calcium 4-oxopentanoate).
  • Urine samples were collected over a 24-hour period post-administration.
  • Excreted metabolites, specifically 4-oxopentanoic acid and 4-hydroxypentanoic acid, were quantified using gas chromatography-mass spectrometry (GC-MS).

Main Results:

  • Excretion of 4-oxopentanoic acid ranged from 3.5 to 11.0 mg/24 h.
  • Excretion of 4-hydroxypentanoic acid ranged from 4.5 to 10.4 mg/24 h.
  • These excreted acids showed structural similarities to those found in beta-ketothiolase deficiency when analyzed by GC-MS.

Conclusions:

  • Intravenous calcium levulinate administration leads to the excretion of 4-oxopentanoic and 4-hydroxypentanoic acids in children.
  • These metabolites can present as potential false positives in GC-MS analysis for beta-ketothiolase deficiency.
  • Clinical laboratories should be aware of this potential diagnostic interference when interpreting results.

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