Courses

What the Heck Does That Laboratory Value Mean?

Presenter: Barbara Marriage, PhD, RD

Program Date: 29 May 2025

Publication Date: 17 November 2025

Continuing Education Credits: Dietitian 1.0 CPEU

Course Description

This course was originally presented at the 2025 Abbott Metabolic Conference. It provides an overview of laboratory biomarkers and their clinical relevance in the identification and diagnosis of inborn errors of metabolism.

Course Objectives:
  • Differentiate among the laboratory tests utilized for screening, diagnosis, monitoring, and research.
  • Identify important markers in amino acid and urea cycle disorders, including the use of plasma amino acids.
  • Recognize significant laboratory tests/values for monitoring fatty acid oxidation disorders.
  • Indicate the utility of laboratory markers for monitoring control in organic acidemias.
Key Takeaways:
  • Correct specimen collection and handling are critical to minimize artifactual alterations of the results.
  • Information regarding diet, nutritional status, clinical status, and medications is necessary to interpret the results of the metabolic tests correctly.
  • Treat the patient, not the blood sample.

Performance Indicators: 9.1.4, 9.2.1, 11.2.12

Activity Code: 190549

Enroll
Related Questions:
  • What are common causes of false positives in newborn screening tests?
    False positives in newborn screening may be caused by factors like total parenteral nutrition (TPN), prematurity, liver disease, and sample handling issues, which can artificially elevate certain metabolites.
  • How do fasting and feeding impact amino acid levels in blood tests?
    Fasting and feeding significantly impact amino acid levels in blood tests: postprandial (after eating) samples tend to show higher levels of many amino acids, especially methionine, leucine, and others. Fasting samples are preferred for consistency, but in practice, especially with infants, it's often difficult to standardize timing, so clinicians must interpret results with context and caution.
  • What is the role of carnitine and acylcarnitine profiles in evaluating energy metabolism?
    Carnitine and acylcarnitine profiles play a key role in evaluating energy metabolism by helping identify fatty acid oxidation (FAO) disorders. Carnitine binds to fatty acids to form acylcarnitines, which facilitate their transport into mitochondria for energy production. In FAO defects, specific acylcarnitines accumulate because they cannot be oxidized, making these profiles useful for diagnosis, monitoring, and assessing treatment effectiveness.
  • What factors can influence the interpretation of metabolic lab values?
    Metabolic lab values can be influenced by sample type and handling, feeding status, medications, underlying health conditions, circadian rhythms, physical activity, and nutritional intake. Accurate interpretation requires considering these factors along with clinical context and patient history.

Course Instructor Bio(s)

Barbara Marriage, PhD, RD

Metabolic Dietitian 
Pediatric Nutrition 
Ontario, CA

Barbara Marriage is a consultant in the area of pediatric nutrition. She was a Senior Associate Research Fellow leading the Pediatric Nutrition Science and Innovation group at Abbott Nutrition until May 2021, where she was responsible for clinical research and scientific support for pediatric products globally. She has held positions as Global Science Lead for Pediatric Specialty Nutrition, Associate Director in Global Regulatory Science and Innovation, and Manager of the Pediatric Clinical Nutrition group. In that role, Barbara was responsible for clinical research in infant nutrition, pediatrics, and maternal nutrition.

She is a graduate of the University of Guelph and completed her Master’s and PhD at the University of Alberta. Her PhD work focused on the nutritional management of mitochondrial disorders. Before joining Abbott in 2002, she worked for over 20 years as a clinical research dietitian with extensive experience in pediatric nutrition and management of patients and families with inborn errors of metabolism.  Her research interests include human milk oligosaccharides, gastrointestinal disorders, allergy, and inborn errors of metabolism. Dr Marriage has published over 30 articles in peer-reviewed journals, written book chapters and newsletters, and has given many presentations on nutrition-related topics.

Category
CPEU Neonatal Disease State
Highlighted References:
  • Abdelmagid SA, et al. PLoS One. 2015;10(2):e0116195.
  • Albrecht J, et al. Biochem Pharmacol. 2010;80(9):303-13081.
  • Baumgartner MR, et al. Orphanet J Rare Dis. 2014;9:130.
  • Brenna JT, et al. Am J Clin Nutr. 2018;108:211-227.
  • Fernández-Lainez C, et al. Curr Med Chem. 2012;19(26):4511-22.
  • Fingerhut R, et al. J Inherit Metab Dis. 2010;33(Suppl 2):S235-S239.
  • Giguère Y, et al. Adv Exp Med Biol. 2017;959:139-146.
  • Gregory CO, et al. Genet Med. 2007;9(11):761-765.
  • Groselj U, et al. Clin Biochem. 2015;48(1-2):14-8.
  • Heireman L, et al. Clin Biochem. 2017;50(18):1317-1322.
  • Ishikura K, et al. J Phys Fitness Sports Med. 2013;2(3):301-310.
  • Kamleh M, et al. J Pediatr Pharmacol Ther. 2021;26(7):723-727.
  • Luciana M, et al. Child Devel. 2001;72(6):1637-1652.
  • Morris M, et al. Genet Med. 2014;16(6):477-483.
  • Oladipo OO, et al. Mol Genet Metab. 2011;104(4):476-479.
  • Ryckman KK, et al. Clin Biochem. 2013;46(1-2):133-8. 
  • Sharman R, et al. J Inherit Metab Dis. 2010;33 Suppl 3:S417-20.
  • Stroup BM, et al. Mol Genet Metab Rep. 2016;16:6:21-6.
  • Watson MS, et al. Int J Neonatal Screen. 2022;8(3):41.

Abbott Nutrition’s Statement for Dietitian CPEUs:

This educational activity has been prior-approved by the Commission on Dietetic Registration (CDR). CDR credentialed practitioners will receive the specified continuing professional education units (CPEUs) for completion of this program/material.