Carnitines/Acylcarnitines

❛❛In clinical chemistry-based applications of mass spectrometry, the first lesson the laboratory learns is the requisite nature of stable isotope-enriched standards for quantification of metabolites in biological fluids. In newborn screening of amino acids and acylcarnitines, Cambridge Isotope Laboratories, Inc., set the standard for quantification of these metabolites in dried blood spots. As research and development of the newborn screening analysis by mass spectrometry progressed, it was clear that a half dozen isotope-labeled internal standards would not be adequate for the analysis of an amino acid and acylcarnitine profile, together comprising a range of 500 separate mass units and more than 30 important metabolites, most of which require accurate quantification. When screening began to expand beyond research, it was clear that weighing out small quantities of individual standards would reduce accuracy and introduce unnecessary error. Therefore, together, we set out to develop sets of standards for amino acids and acylcarnitine analysis that would enable quantification. We started this development more than 20 years ago adding, changing, and improving these standards. CIL, together with the early developers of tandem mass spectrometry-based newborn screening, set the standard by which all other laboratories follow. CIL’s commitment to supporting the metabolic and newborn screening community is exceptional. It is our good fortune in the clinical chemistry and mass spectrometry community to have CIL as part of our laboratory solutions.❜❜

– Donald H. Chace, PhD MSFS FACB | Medolac Laboratories

❛❛We have been using CIL’s NSK-A and NSK-B reference standards in our LC-MS/MS method for newbom screening tests since 2001. From that time more than 4,000,000 newborns have been screened. The products maintain good stability after dissolution and the high analysis repeatability enabled us to stabilize their use as internal standards. We appreciate the high-quality products, timely deliveries, and excellent customer relations.❜❜

– Mariusz Oltarzewsk | Head of Department of Screening Tests and Metabolic Diagnostics, Institute of Mother and Child (Poland)

Individual Standards

He, W.; Berthiaume, J.M.; Previs, S.; et al. 2023. Ischemia promotes acyl-CoAs dephosphorylation and propionyl-CoA accumulation. Metabolomics, 19(2), 12-26. PMID: 36750484
Mak, J.; Peng, G.; Le, A.; et al. 2023. Validation of a targeted metabolomics panel for improved second-tier newborn screening. J Inherit Metab Dis, 46(2), 194-205. PMID: 36680545
Al-Riyami, S.; Al-Manei, M.; Al-Fahdi, A.; et al. 2022. Establishment and validation of reference values for amino acids and acylcarnitines in dried blood spots for Omani newborns using tandem mass spectrometry. Oman Med J, 37(5), e426-e432.  PMID: 36188883
Wang, W.Y.; Liu, X.; Gao, X-Q.; et al. 2022. Relationship between acylcarnitine and the risk of retinopathy in type 2 diabetes mellitus. Front Endocrinol, 13, 834205-834213.  PMID: 35370967

Mixtures

Tan, H.C.; Hsu, J.W.; Tai, E.S.; et al. 2024. The impact of obesity-associated glycine deficiency on the elimination of endogenous and exogenous metabolites via the glycine conjugation pathway. Front Endocrinol, 15, 1343738-1343749.  PMID: 38633754
Zong, G.-W.; Wang, W.-Y.; Zheng, J.; et al. 2023. A metabolism-based interpretable machine learning prediction model for diabetic retinopathy risk: a cross-sectional study in Chinese patients with type 2 diabetes. J Diabetes Res, 2023, 3990035-3990046.  PMID: 37229505
Pruss, K.M.; Chen, H.; Liu, Y.; et al. 2023. Host-microbe co-metabolism via MCAD generates circulating metabolites including hippuric acid. Nat Commun, 14(1), 512-523.  PMID: 36720857
Mak, J.; Peng, G.; Le, A.; et al. 2023. Validation of a targeted metabolomics panel for improved second-tier newborn screening. J Inherit Metab Dis, 46(2), 194-205.  PMID: 36680545
Huguenard, C.J.C.; Cseresznye, A.; Darcey, T.; et al. 2023. Age and APOE affect L-carnitine system metabolites in the brain in the APOE-TR model. Front Aging Neurosci, 14, 1059017-1059035.  PMID: 36688151

Technical Note

Xie, X.; Kozak, M. 2020. Simultaneous analysis of amino acids, acylcarnitines, and succinylacetone in dried blood spots for research using nonderivatized and derivatized methods. (Thermo Scientific technical note #73398 ).