Long-term stability of amino acids and acylcarnitines in dried blood spots

Kristina Anna Strnadová, Margareta Holub, Adolf Mühl, Georg Heinze, Rene Ratschmann, Hermann Mascher, Sylvia Stöckler-Ipsiroglu, Franz Waldhauser, Felix Votava, Jan Lebl, Olaf A. Bodamer

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52 Scopus citations

Abstract

Background: Dried blood filter cards, collected for newborn screening, are often stored for long periods of time. They may be suitable for the retrospective diagnosis of inborn errors of metabolism, but no data are currently available on the long-term stability of amino acids and acylcarnitine species. Methods: We analyzed amino acids and acylcarnitines by tandem mass spectrometry in 660 anonymous, randomly selected filter cards from 1989 through 2004. We assessed long-term stability of metabolites by linear regression and estimated annual decrease of concentration for each metabolite. Results: Concentrations of free carnitine increased by 7.6% per year during the first 5 years of storage and decreased by 1.4% per year thereafter. Alanine, arginine, leucine, methionine, and phenylalanine decreased by 6.5%, 3.3%, 3.1%, 7.3%, and 5.7% per year, respectively. Acetylcarnitine, propionylcarnitine, citrulline, glycine, and ornithine decreased by 18.5%, 27.4%, 8.1%, 14.7%, and 16.3% per year during the first 5 years, respectively; thereafter the decline was more gradual. Tyrosine decreased by 1.7% per year during the first 5 years and 7.9% per year thereafter. We could not analyze medium-and long-chain acylcarnitine species because of low physiological concentrations. Conclusions: Estimation of the annual decrease of metabolites may allow for the retrospective diagnosis of inborn errors of metabolism in filter cards that have been stored for long periods of time.

Original languageEnglish (US)
Pages (from-to)717-722
Number of pages6
JournalClinical chemistry
Volume53
Issue number4
DOIs
StatePublished - Apr 1 2007

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Biochemistry, medical

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    Strnadová, K. A., Holub, M., Mühl, A., Heinze, G., Ratschmann, R., Mascher, H., Stöckler-Ipsiroglu, S., Waldhauser, F., Votava, F., Lebl, J., & Bodamer, O. A. (2007). Long-term stability of amino acids and acylcarnitines in dried blood spots. Clinical chemistry, 53(4), 717-722. https://doi.org/10.1373/clinchem.2006.076679