BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuPlasma amino acidsAmino acids blood testPlasma amino acids is a screening test, usually done on infants that looks at the amounts of amino acids in the blood. Amino acids are the building blocks for proteins in the body.Amino acidsAmino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or bro...ImageRead Article Now Book Mark Article How the Test is Performed Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand.In infants or young children, a sharp tool called a lancet may be used to puncture the skin.The blood collects in a small glass tube called a pipette, or onto a slide or test strip. A bandage is put over the spot to stop any bleeding.The blood sample is sent to a lab. There are several types of methods used to determine the individual amino acid levels in the blood. How to Prepare for the Test The person having the test may be asked not to eat 3 or more hours before the test. Check with your child's health care provider for specific advice. How the Test will Feel There might be slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn. The needle stick will probably cause an infant or child to cry. Why the Test is Performed This test is done to measure the level of amino acids in the blood.An increased level of a particular amino acid shows that there is a problem with the body's ability to break down (metabolize) that amino acid.The test may also be used to look for decreased levels of amino acids in the blood.Increased or decreased levels of amino acids in the blood may occur with fevers, inadequate nutrition, and certain medical conditions. Normal Results All measurements are in micromoles per liter (µmol/L). In children, normal values vary with age. In addition, normal values may vary between different laboratories. Talk to your provider about your specific test results.Alanine:Children: 156 to 598 Adults: 125 to 564Alpha-aminoadipic acid:Children: 0 to 2 Adults: 0 to 2Alpha-amino-N-butyric acid:Children: 6 to 34 Adults: 5 to 34Arginine:Children: 33 to 122 Adults: 32 to 150Asparagine:Children: 32 to 101 Adults: 30 to 85Aspartic acid:Children: 1 to 8 Adults: 1 to 7Beta-alanine:Children: 1 to 8 Adults: 1 to 9Beta-amino-isobutyric acid:Children: 0 to 3 Adults: 0 to 4Carnosine:Children: not detected Adults: not detectedCitrulline:Children: 12 to 47 Adults: 14 to 63Cystine:Children: 9 to 36 Adults: 14 to 60Glutamic acid:Children: 18 to 142 Adults: 18 to 156Glutamine:Children: 330 to 726 Adults: 332 to 754Glycine:Children: 129 to 430 Adults: 132 to 467Histidine:Children: 50 to 104 Adults: 47 to 99Hydroxyproline:Children: 9 to 45 Adults: 5 to 35Isoleucine:Children: 28 to 110 Adults: 28 to 113 Leucine:Children: 57 to 194 Adults: 55 to 205Lysine:Children: 83 to 240 Adults: 94 to 278Methionine:Children: 13 to 40 Adults: 13 to 411-methylhistidine:Children: not detected Adults: not detected3-methylhistidine:Children: 0 to 52 Adults: 0 to 64Ornithine:Children: 27 to 136 Adults: 31 to 131 Phenylalanine:Children: 32 to 103 Adults: 34 to 102Phosphoserine:Children: 0 to 12 Adults: 0 to 12Phosphoethanolamine:Children: 0 to 12 Adults: 0 to 55Proline:Children: 85 to 365 Adults: 85 to 353Serine:Children: 60 to 172 Adults: 49 to 145 Taurine:Children: 33 to 126 Adults: 29 to 132Threonine:Children: 56 to 193 Adults: 68 to 212Tyrosine:Children: 32 to 123 Adults: 31 to 118Valine:Children: 110 to 334 Adults: 103 to 345The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens. What Abnormal Results Mean An increase in the total level of amino acids in the blood may be due to:Eclampsia EclampsiaEclampsia is the new onset of seizures or coma in a pregnant woman with preeclampsia. These seizures are not related to an existing brain condition....ImageRead Article Now Book Mark Article Inborn error of metabolism Inborn error of metabolismInborn errors of metabolism are rare genetic (inherited) disorders in which the body cannot properly turn food into energy. The disorders are usuall...ImageRead Article Now Book Mark Article Fructose intolerance Fructose intoleranceHereditary fructose intolerance is a disorder in which a person lacks the protein needed to break down fructose. Fructose is a fruit sugar that natu...Read Article Now Book Mark Article Ketoacidosis (from diabetes) KetoacidosisDiabetic ketoacidosis (DKA) is a life-threatening problem that affects people with diabetes. It occurs when the body starts breaking down fat at a r...ImageRead Article Now Book Mark Article Kidney failure Reye syndrome Reye syndromeReye syndrome is characterized by sudden (acute) brain damage and liver function problems. This condition does not have a known cause. This syndrome...ImageRead Article Now Book Mark Article Laboratory errorA decrease in the total level of amino acids in the blood may be due to:Adrenal cortical hyperfunction Fever Hartnup disease Hartnup diseaseHartnup disorder is a genetic condition in which there is a defect in the transport of certain amino acids (such as tryptophan and histidine) by the ...Read Article Now Book Mark Article Inborn error of metabolism Huntington chorea Malnutrition MalnutritionMalnutrition is the condition that occurs when your body does not get enough nutrients.ImageRead Article Now Book Mark Article Nephrotic syndrome Nephrotic syndromeNephrotic syndrome is a group of symptoms and abnormal test results that include protein in the urine, low blood protein levels in the blood, high ch...ImageRead Article Now Book Mark Article Phlebotomus fever Rheumatoid arthritis Rheumatoid arthritisRheumatoid arthritis (RA) is a disease that leads to inflammation of the joints and surrounding tissues. It is a long-term disease. It can also aff...ImageRead Article Now Book Mark Article Laboratory errorHigh or low amounts of individual plasma amino acids must be considered with other information. Abnormal results may be due to diet, hereditary problems, or effects of a medicine. Considerations Screening infants for increased levels of amino acids can help detect problems with metabolism. Early treatment for these conditions may prevent complications in the future.Open ReferencesReferencesDietzen DJ, Vieira Willrich MA. Amino acids, peptides, and proteins. In: Rifai N, Chiu RWK, Young I, Burnham C-A D, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. St Louis, MO: Elsevier; 2023:chap 31.Kliegman RM, St. Geme JW, Blum NJ, et al. Defects in metabolism of amino acids. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 105.McPherson RA. Specific proteins. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 20.Merritt JL, Gallagher RC. Inborn errors of carbohydrate, ammonia, amino acid, and organic acid metabolism. In: Gleason CA, Sawyer T, eds. Avery's Diseases of the Newborn. 11th ed. Philadelphia, PA: Elsevier; 2024:chap 29.AllVideoImagesTogAmino acids - illustration Amino acids are either essential, which must be supplied by food, or nonessential, which are made in the body.Amino acidsillustrationAmino acids - illustration Amino acids are either essential, which must be supplied by food, or nonessential, which are made in the body.Amino acidsillustration Tests for Plasma amino acids Plasma amino acidsRelated Information Metabolism(Special Topic)Intellectual disability(Condition)Chronic kidney disease(Condition)Acute kidney failure(Condition)Eclampsia(Condition)Reye syndrome(Condition)Diabetic ketoacidosis(Condition)Diabetes(Condition)Rheumatoid arthritis(Condition)Huntington disease(Condition)Diabetes - type 1 - InDepth(In-Depth)Rheumatoid arthritis - InDepth(In-Depth) Review Date: 4/8/2025 Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. © 1997- All rights reserved. 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Plasma amino acidsAmino acids blood testPlasma amino acids is a screening test, usually done on infants that looks at the amounts of amino acids in the blood. Amino acids are the building blocks for proteins in the body.Amino acidsAmino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or bro...ImageRead Article Now Book Mark Article How the Test is Performed Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand.In infants or young children, a sharp tool called a lancet may be used to puncture the skin.The blood collects in a small glass tube called a pipette, or onto a slide or test strip. A bandage is put over the spot to stop any bleeding.The blood sample is sent to a lab. There are several types of methods used to determine the individual amino acid levels in the blood. How to Prepare for the Test The person having the test may be asked not to eat 3 or more hours before the test. Check with your child's health care provider for specific advice. How the Test will Feel There might be slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn. The needle stick will probably cause an infant or child to cry. Why the Test is Performed This test is done to measure the level of amino acids in the blood.An increased level of a particular amino acid shows that there is a problem with the body's ability to break down (metabolize) that amino acid.The test may also be used to look for decreased levels of amino acids in the blood.Increased or decreased levels of amino acids in the blood may occur with fevers, inadequate nutrition, and certain medical conditions. Normal Results All measurements are in micromoles per liter (µmol/L). In children, normal values vary with age. In addition, normal values may vary between different laboratories. Talk to your provider about your specific test results.Alanine:Children: 156 to 598 Adults: 125 to 564Alpha-aminoadipic acid:Children: 0 to 2 Adults: 0 to 2Alpha-amino-N-butyric acid:Children: 6 to 34 Adults: 5 to 34Arginine:Children: 33 to 122 Adults: 32 to 150Asparagine:Children: 32 to 101 Adults: 30 to 85Aspartic acid:Children: 1 to 8 Adults: 1 to 7Beta-alanine:Children: 1 to 8 Adults: 1 to 9Beta-amino-isobutyric acid:Children: 0 to 3 Adults: 0 to 4Carnosine:Children: not detected Adults: not detectedCitrulline:Children: 12 to 47 Adults: 14 to 63Cystine:Children: 9 to 36 Adults: 14 to 60Glutamic acid:Children: 18 to 142 Adults: 18 to 156Glutamine:Children: 330 to 726 Adults: 332 to 754Glycine:Children: 129 to 430 Adults: 132 to 467Histidine:Children: 50 to 104 Adults: 47 to 99Hydroxyproline:Children: 9 to 45 Adults: 5 to 35Isoleucine:Children: 28 to 110 Adults: 28 to 113 Leucine:Children: 57 to 194 Adults: 55 to 205Lysine:Children: 83 to 240 Adults: 94 to 278Methionine:Children: 13 to 40 Adults: 13 to 411-methylhistidine:Children: not detected Adults: not detected3-methylhistidine:Children: 0 to 52 Adults: 0 to 64Ornithine:Children: 27 to 136 Adults: 31 to 131 Phenylalanine:Children: 32 to 103 Adults: 34 to 102Phosphoserine:Children: 0 to 12 Adults: 0 to 12Phosphoethanolamine:Children: 0 to 12 Adults: 0 to 55Proline:Children: 85 to 365 Adults: 85 to 353Serine:Children: 60 to 172 Adults: 49 to 145 Taurine:Children: 33 to 126 Adults: 29 to 132Threonine:Children: 56 to 193 Adults: 68 to 212Tyrosine:Children: 32 to 123 Adults: 31 to 118Valine:Children: 110 to 334 Adults: 103 to 345The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens. What Abnormal Results Mean An increase in the total level of amino acids in the blood may be due to:Eclampsia EclampsiaEclampsia is the new onset of seizures or coma in a pregnant woman with preeclampsia. These seizures are not related to an existing brain condition....ImageRead Article Now Book Mark Article Inborn error of metabolism Inborn error of metabolismInborn errors of metabolism are rare genetic (inherited) disorders in which the body cannot properly turn food into energy. The disorders are usuall...ImageRead Article Now Book Mark Article Fructose intolerance Fructose intoleranceHereditary fructose intolerance is a disorder in which a person lacks the protein needed to break down fructose. Fructose is a fruit sugar that natu...Read Article Now Book Mark Article Ketoacidosis (from diabetes) KetoacidosisDiabetic ketoacidosis (DKA) is a life-threatening problem that affects people with diabetes. It occurs when the body starts breaking down fat at a r...ImageRead Article Now Book Mark Article Kidney failure Reye syndrome Reye syndromeReye syndrome is characterized by sudden (acute) brain damage and liver function problems. This condition does not have a known cause. This syndrome...ImageRead Article Now Book Mark Article Laboratory errorA decrease in the total level of amino acids in the blood may be due to:Adrenal cortical hyperfunction Fever Hartnup disease Hartnup diseaseHartnup disorder is a genetic condition in which there is a defect in the transport of certain amino acids (such as tryptophan and histidine) by the ...Read Article Now Book Mark Article Inborn error of metabolism Huntington chorea Malnutrition MalnutritionMalnutrition is the condition that occurs when your body does not get enough nutrients.ImageRead Article Now Book Mark Article Nephrotic syndrome Nephrotic syndromeNephrotic syndrome is a group of symptoms and abnormal test results that include protein in the urine, low blood protein levels in the blood, high ch...ImageRead Article Now Book Mark Article Phlebotomus fever Rheumatoid arthritis Rheumatoid arthritisRheumatoid arthritis (RA) is a disease that leads to inflammation of the joints and surrounding tissues. It is a long-term disease. It can also aff...ImageRead Article Now Book Mark Article Laboratory errorHigh or low amounts of individual plasma amino acids must be considered with other information. Abnormal results may be due to diet, hereditary problems, or effects of a medicine. Considerations Screening infants for increased levels of amino acids can help detect problems with metabolism. Early treatment for these conditions may prevent complications in the future.Open ReferencesReferencesDietzen DJ, Vieira Willrich MA. Amino acids, peptides, and proteins. In: Rifai N, Chiu RWK, Young I, Burnham C-A D, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. St Louis, MO: Elsevier; 2023:chap 31.Kliegman RM, St. Geme JW, Blum NJ, et al. Defects in metabolism of amino acids. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 105.McPherson RA. Specific proteins. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 20.Merritt JL, Gallagher RC. Inborn errors of carbohydrate, ammonia, amino acid, and organic acid metabolism. In: Gleason CA, Sawyer T, eds. Avery's Diseases of the Newborn. 11th ed. Philadelphia, PA: Elsevier; 2024:chap 29.
