Chemical Pathology


Acylcarnitines are biological intermediates that play a vital role in energy production. They are involved in critical energy production during times of prolonged fasting and increased calorific requirement.

Acylcarnitine measurement is used in the diagnosis and monitoring of fatty acid oxidation disorders. An example is medium chain acyl CoA dehydrogenase deficiency (MCADD), which is the most common disorder of fatty acid metabolism and is part of the newborn screening programme.

Analysis can detect around 24 disorders. Each fatty acid oxidation disorder is associated with a specific enzyme defect in the fatty acid metabolic pathway and affects utilization of dietary and stored fat. As such, fatty acid oxidation disorders can cause recurrent episodes of hypoglycemia. Clinical findings may include lethargy, hypotonia, failure to thrive, persistent vomiting, hepatomegaly, rhabdomyolysis and Reye syndrome-like episodes.

Sample requirements

Dried blood spots: capillary blood is collected by natural flow from the neonate heel and applied to four printed circles on the Scheiller & Scull 903 filter paper section of the sample card from approved suppliers.

Spots can also be made up using blood taken into a minicollect lithium heparin tube

Sample tube: pale green cap


Send at ambient temperature to the laboratory on same day as sample collection.

Required information

Relevant clinical details including details of clinical presentation.

Turnaround times

Samples are sent for analysis to the North Bristol NHS Trust with a result expected within 4 weeks.

Reference ranges

Not reported, instead an interpretative report is supplied as the individual quantitative results support the interpretation of the acylcarnitine profile but are not diagnostic in and of themselves.

Further information

To learn more about acylcarnitines visit National Metabolic Biochemistry Network

Page last updated; 20/04/2021