The Blood spot Amino Acid Assay is a finger stick amino acid test that measures all of the essential plus key nonessential amino acids. Fasting levels of amino acids represent homeostatic balance between supply and utilization of these critical building blocks. The Blood spot Amino Acid Assay is a non-invasive alternative to the blood draw in determining essential amino acid status. The test kit is simple enough for the patient to use at home. A formula for a custom amino acid blend is provided with every blood spot amino acid test result. This blend can be made by any compounding pharmacy.