Dietary monitoring with amino acid analysis is crucial for management of many inborn errors of metabolism. The gold standard for this type of monitoring is plasma amino acid analysis, which offers quantitative results for more than 20 amino acids. Plasma analysis requires a blood draw with its associated costs, and often has a list price of over $100. Home monitoring using dried blood spots collected on filter paper (similar to what is used in newborn screening) can provide accurate results for a selected subset of amino acids important for a selected disorder, such as maple syrup urine disease (MSUD). This type of sample can be collected at home, and sent to the testing laboratory by regular mail.
The Biochemical Genetics Laboratory at EGL Genetic Diagnostics, LLC provides filter paper monitoring designed specifically for MSUD and phenylketonuria. Our MSUD filter paper assay provides quantitative values for valine, leucine, isoleucine and allo isoleucine, along with reference ranges, and a comparison to a targeted therapeutic range for leucine. Testing is done using liquid chromatography and tandem mass spectrometry. This assay is performed weekly and results are reported back to the ordering provider by fax. Turn-around time is seven days. Additional information about this assay can be found on our webpage (http://geneticslab. emory.edu/tests/BMSUD). For the specimen, we require at least one completely filled and saturated circle on a standard filter paper card. Requisition forms are available on our website, and can be customized upon request. The tests are ordered through a clinician and no direct consumer testing is available.
Our team’s observations and feedback from the patients indicate that if fulfills a great gap to improve adherence to treatment. Our perspective indicates that patients receive the balanced and frequent nutrition therapy necessary to achieve optimal health and quality of life while remaining independent and comfortable in their own homes for most parts and yet connected to their clinicians. Frequent amino acid monitoring by this method in the outpatient setting along with proper diet analysis and management contributes significantly to improved outcomes. Nutrition management guideline for maple syrup urine disease including the monitoring section based on an evidence- and consensus-based approach are now available at Southeast Regional Genetics Collaborative (SERC) and Genetics Metabolic Dietitians International (GMDI) . For diet analysis you should contact your clinic dietitian.
Home Monitoring of Branched Chain Amino Acids (BCAA) Blood Concentrations
- Written by Patricia Hall, PhD, FACMG; Rani H Singh, PhD, RD, LD. Emory University, Department of Human Genetics