Performance of succinylacetone assays and their associated proficiency testing outcomes

Clin Biochem. 2012 Dec;45(18):1658-63. doi: 10.1016/j.clinbiochem.2012.08.007. Epub 2012 Aug 11.

Abstract

Background: Succinylacetone (SUAC) is the primary metabolic marker for hepatorenal tyrosinemia.

Materials and methods: We used results reported for dried-blood-spot proficiency testing (PT) specimens and hepatorenal tyrosinemia patients' newborn screening (NBS) samples to demonstrate analytic biases in SUAC recoveries and differences in presumptive clinical classifications.

Results: SUAC recoveries from non-kit and NeoBase™ kit tandem mass spectrometry methods were markedly different. Kit users that set high cutoff values submitted discordant clinical assessments of "within normal limits" for PT specimens enriched with 10-15 μmol SUAC/L in blood. SUAC levels in tyrosinemia patients' NBS samples analyzed by NeoBase™ kit were lower than those in samples analyzed by non-kit methods.

Conclusions: From 2009 to 2011, analytic biases in SUAC recoveries were consistent. Discordant clinical assessments of PT specimens were associated with high cutoff values for NeoBase™ kit results. Method-related differences in SUAC concentrations of tyrosinemia patients' samples were consistent with those of PT specimens.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Biological Assay / methods*
  • Biological Assay / standards*
  • Dried Blood Spot Testing
  • Heptanoates / blood*
  • Humans
  • Infant, Newborn
  • Laboratory Proficiency Testing / methods*
  • Laboratory Proficiency Testing / standards*
  • Linear Models
  • Neonatal Screening
  • Tandem Mass Spectrometry

Substances

  • Heptanoates
  • succinylacetone