Diagnosis

MCAD deficiency is diagnosed through newborn screening followed by genetic testing.

• Newborn screening. In the U.S., all states screen for MCAD deficiency at birth. If screening levels are abnormal, additional testing can be done.
• Genetic testing. Genetic testing can reveal the abnormal gene that causes MCAD deficiency. Depending on the type of test, a sample of blood, skin or other tissue is collected and sent to a lab for analysis. Your doctor may also recommend testing family members for this gene. Talk with your doctor, a medical geneticist or a genetic counselor about the testing process and what the results mean.

Episodes of low blood sugar (hypoglycemia) thought to be caused by MCAD deficiency are evaluated by a discussion of signs and symptoms, as well as dietary habits, usually followed by lab tests to identify problems with metabolism and treat or prevent complications.