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Test Code AAQP Amino Acids, Quantitative, Plasma

Reporting Name

Amino Acids, QN, P

Useful For

Evaluating patients with possible inborn errors of metabolism using plasma specimens

 

May aid in evaluation of endocrine disorders, liver diseases, muscle diseases, neoplastic diseases, neurological disorders, nutritional disturbances, kidney failure, and burns

 

Monitoring of patients treated for various inborn errors of metabolism or other causes of amino acid imbalances

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Plasma


Ordering Guidance


Body fluids are not acceptable specimens for this test.

For testing urine specimens, order AAPD / Amino Acids, Quantitative, Random, Urine.

For testing spinal fluid specimens, order AACSF / Amino Acids, Quantitative, Spinal Fluid.



Additional Testing Requirements


Not all patients with homocystinuria/homocystinemia will be detected by this assay. For quantitation of total homocysteine, order CMMPP / Cobalamin, Methionine, and Methylmalonic Acid Pathways, Plasma or HCYSP / Homocysteine, Total, Plasma in conjunction with this amino acids profile.



Shipping Instructions


 



Necessary Information


1. Patient's age is required.

2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.



Specimen Required


Patient Preparation: Patient should fast overnight (4 hours minimum); infants should have specimen collected before next feeding (2-3 hours without total parenteral nutrition if possible).

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Green top (sodium heparin)

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions:

1. Collect specimen and place on wet ice. Note: Thrombin-activated tubes should not be used for collection.

2. Centrifuge immediately or within 4 hours of collection if the specimen is kept at refrigerated temperature.

3. Being careful to ensure that no buffy coat is transferred, aliquot plasma into a plastic vial and freeze.


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Frozen 14 days

Reference Values

Amino acids

Age groups

<24 months

2-17 years

≥18 years

Taurine (Tau)

31-354

32-181

21-123

Asparagine (Asn)

18-94

25-80

23-94

Serine (Ser)

59-224

53-166

55-146

Hydroxyproline (Hyp)

<121

<73

<38

Glycine (Gly)

80-500

80-500

80-500

Glutamine (Gln)

356-857

353-790

447-774

Aspartic Acid (Asp)

<48

<17

<13

Ethanolamine (EtN)

<70

<30

<20

Histidine (His)

46-147

56-119

61-120

Threonine (Thr)

49-358

48-205

73-325

Citrulline (Cit)

8-42

12-44

18-57

Sarcosine (Sar)

<20

<20

<20

b-Alanine (bAla)

<36

<36

<36

Alanine (Ala)

139-474

144-557

200-579

Glutamic Acid (Glu)

28-376

16-182

13-148

1-Methylhistidine (1MHis)

<12

<12

<12

3-Methylhistidine (3MHis)

<11

<30

<35

Argininosuccinic Acid (Asa)

<5

<5

<5

Homocitruline (Hcit)

<5

<2

<2

Arginine (Arg)

28-164

28-156

45-144

a-Aminoadipic Acid (Aad)

<4

<4

<4

g-Amino-n-butyric Acid (GABA)

<4

<4

<4

b-Aminoisobutyric Acid (bAib)

<9

<5

<5

a-Amino-n-butyric Acid (Abu)

<40

<40

<40

Hydroxylysine (Hyl)

<4

<4

<4

Proline (Pro)

102-342

99-389

107-383

Ornithine (Orn)

32-171

32-148

39-154

Cystathionine (Cth)

<4

<4

<4

Cystine (Cys)

6-131

3-151

8-310

Lysine (Lys)

83-304

61-291

105-335

Methionine (Met)

12-57

13-41

13-40

Valine (Val)

94-382

111-367

134-357

Tyrosine (Tyr)

27-188

36-133

36-113

Isoleucine (IIe)

23-149

26-150

29-153

Leucine (Leu)

59-213

51-216

79-217

Phenylalanine (Phe)

36-105

38-116

45-106

Tryptophan (Trp)

12-103

21-114

21-108

Alloisoleucine (Allolle)

<5

<5

<5

 

All results reported in nmol/mL

Day(s) Performed

Monday through Friday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

82139

LOINC Code Information

Test ID Test Order Name Order LOINC Value
AAQP Amino Acids, QN, P 35083-5

 

Result ID Test Result Name Result LOINC Value
3570 Interpretation (AAQP) 49247-0
3512 Taurine 20657-3
3517 Asparagine 20638-3
3516 Serine 20656-5
34458 Hydroxyproline 20647-4
3522 Glycine 20644-1
3518 Glutamine 20643-3
34459 Aspartic Acid 20639-1
34460 Ethanolamine 26608-0
3535 Histidine 20645-8
3515 Threonine 20658-1
3521 Citrulline 20640-9
34461 Sarcosine 26613-0
3532 Beta-Alanine 26604-9
3523 Alanine 20636-7
3520 Glutamic Acid 20642-5
34453 1-Methylhistidine 20633-4
34454 3-Methylhistidine 20635-9
32341 Argininosuccinic Acid 32227-1
34456 Homocitrulline 55876-7
3536 Arginine 20637-5
34450 Alpha-aminoadipic Acid 26600-7
34463 Gamma-amino-n-butyric Acid 26609-8
34452 Beta-aminoisobutyric Acid 26605-6
3524 Alpha-amino-n-butyric Acid 20634-2
34464 Hydroxylysine 26610-6
3519 Proline 20655-7
3533 Ornithine 20652-4
34451 Cystathionine 26607-2
3526 Cystine 22672-0
3534 Lysine 20650-8
3527 Methionine 20651-6
3525 Valine 20661-5
3530 Tyrosine 20660-7
3528 Isoleucine 20648-2
3529 Leucine 20649-0
3531 Phenylalanine 14875-9
34465 Tryptophan 20659-9
32347 Allo-isoleucine 22670-4

Disease States

  • Alkaptonuria
  • Homocystinuria

Clinical Information

Amino acids are the basic structural units that comprise proteins and are found throughout the body. Many inborn errors of amino acid metabolism, such as phenylketonuria and tyrosinemia, have been identified. Amino acid disorders can manifest at any age, but most become evident in infancy or early childhood. These disorders result in the accumulation or the deficiency of 1 or more amino acids in biological fluids, which leads to the clinical signs and symptoms of the specific amino acid disorder.

 

The clinical presentation is dependent upon the specific amino acid disorder. In general, affected patients may experience failure to thrive, neurologic symptoms, digestive problems, dermatologic findings, and physical and cognitive delays. If not diagnosed and treated promptly, amino acid disorders can result in intellectual disabilities and, possibly, death.

 

Treatment for amino acid disorders includes very specific dietary modifications. Nonessential amino acids are synthesized by the body, while essential amino acids are not and must be obtained through an individual's diet. Therapeutic diets are coordinated and closely monitored by a dietician or physician. They are structured to provide the necessary balance of amino acids with particular attention to essential amino acids and those that are abnormal in a particular disorder. Patients must pay close attention to the protein content in their diet and generally need to supplement with medical formulas and foods. Dietary compliance is monitored by periodic analysis of plasma amino acids.

 

In addition, plasma amino acid analysis may have clinical importance in the evaluation of several acquired conditions, including endocrine disorders, liver diseases, muscle diseases, neoplastic diseases, neurological disorders, nutritional disturbances, kidney failure, and burns.

Interpretation

When no significant abnormalities are detected, a simple descriptive interpretation is provided. When abnormal results are detected, a detailed interpretation is given, including an overview of the results and their significance, a correlation to available clinical information, elements of differential diagnosis, recommendations for additional biochemical testing, and in vitro confirmatory studies (enzyme assay, molecular analysis), name and phone number of key contacts who may provide these studies, and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.

Cautions

Reference values are for fasting patients.

 

Patients with phenylketonuria (PKU) who are treated with pegvaliase-pqpz (Palynziq) may have false low phenylalanine concentrations due to persistent activity in collected blood specimens.

 

This assay does not measure total homocysteine. If relevant disorders are considered, also order CMMPP / Cobalamin, Methionine, and Methylmalonic Acid Pathways, Plasma or HCYSP / Homocysteine, Total, Plasma analysis.

Clinical Reference

1. Part 8: Amino Acids. In: Valle DL, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA. eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill, 2019. Accessed October 24, 2024 Available at https://ommbid.mhmedical.com/book.aspx?bookID=2709#225069340

2. Pasquali M, Longo N: Amino acids. In: Blau N, Dionisi Vici C, Ferreira CR, Vianey-Saban C, van Karnebeek CDM, eds. Physician's Guide to the Diagnosis, Treatment and Follow-up of Inherited Metabolic Diseases. 2nd ed. Springer-Verlag; 2022:41-50

Method Description

Quantitative analysis of amino acids is performed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Patient samples are combined with isotopically labeled internal standard. Following protein precipitation, the supernatant is subjected to hydrophilic interaction liquid chromatography for the separation of isomers with MS/MS detection of the underivatized amino acids.(Unpublished Mayo method)

Report Available

3 to 5 days

Specimen Retention Time

2 weeks

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Testing Algorithm

Testing includes quantitation of the following amino acids: taurine, threonine, serine, asparagine, glutamic acid, glutamine, proline, alanine, citrulline, alpha-amino-n-butyric acid, valine, cystine, methionine, isoleucine, leucine, tyrosine, phenylalanine, beta-alanine, ornithine, lysine, histidine, argininosuccinic acid, allo-isoleucine, arginine, hydroxyproline, glycine, aspartic acid, ethanolamine, sarcosine, 1-methylhistidine, 3-methylhistidine, homocitrulline, alpha-aminoadipic acid, gamma-amino-n-butyric acid, beta-aminoisobutyric acid, hydroxylysine, cystathionine, and tryptophan.

 

For more information see Epilepsy: Unexplained Refractory and/or Familial Testing Algorithm.

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Portions of this test are covered by patents held by Quest Diagnostics