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Test ID AACSF Amino Acids, Quantitative, Spinal Fluid

Reporting Name

Amino Acids, QN, CSF

Useful For

Evaluating patients with possible inborn errors of amino acid metabolism, particularly nonketotic hyperglycinemia (glycine encephalopathy) and serine biosynthesis defects, especially when used in conjunction with concomitantly collected plasma specimens

Specimen Type

CSF


Additional Testing Requirements


This test should be ordered in conjunction with AAQP / Amino Acids, Quantitative, Plasma. The specimens for both tests (AAQP / Amino Acids, Quantitative, Plasma and this test) should be collected at the same time.



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


Container/Tube: Sterile vial

Specimen Volume: 0.2 mL

Collection Instructions: Collect specimen from second collection vial.


Specimen Minimum Volume

0.1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Frozen 14 days

Reference Values

Amino Acid

Age groups

≤31 days

32 days-23 months

2-18 years

≥19 years

Taurine (Tau)

8-28

4-13

4-10

3-9

Asparagine (Asn)

7-25

5-17

4-12

5-14

Serine (Ser)

43-127

37-87

22-57

18-58

Hydroxyproline (Hyp)

<12

<8

<3

<3

Glycine (Gly)

<60

<27

<20

<28

Glutamine (Gln)

447-1547

384-716

375-770

452-1283

Aspartic Acid (Asp)

<12

<12

<12

<12

Ethanolamine (EtN)

11-152

6-41

7-25

6-24

Histidine (His)

19-63

12-32

9-26

12-36

Threonine (Thr)

35-212

19-89

13-51

13-57

Citrulline (Cit)

<6

<5

<4

<4

Sarcosine (Sar)

<21

<21

<21

<21

Beta-alanine (bAla)

<17

<17

<17

<17

Alanine (Ala)

20-92

18-69

16-54

22-80

Glutamic Acid (Glu)

<12

<4

<3

<2

1-Methylhistidine (1MHis)

<5

<1

<1

<3

3-Methylhistidine (3MHis)

<4

<1

<3

<5

Argininosuccinic Acid (Asa)

<4

<4

<4

<4

Homocitrulline (Hcit)

<1

<1

<1

<1

Arginine (Arg)

7-37

11-36

13-30

14-32

Alpha-aminoadipic Acid (Aad)

<2

<2

<2

<2

Gamma-amino-n-butyric Acid (GABA)

<10

<10

<10

<10

Beta-aminoisobutyric Acid (bAib)

<1

<1

<1

<1

Alpha-amino-n-butyric Acid (Abu)

<21

<7

<5

<10

Hydroxylysine (Hyl)

<1

<1

<1

<1

Proline (Pro)

<14

<4

<4

<2

Ornithine (Orn)

<32

<15

<12

<15

Cystathionine (Cth)

<4

<1

<1

<2

Cystine (Cys)

<3

<3

<3

<3

Lysine (Lys)

16-67

17-41

13-45

23-54

Methionine (Met)

<19

<7

<5

<12

Valine (Val)

16-83

10-36

10-27

13-52

Tyrosine (Tyr)

<70

<22

<16

<65

Isoleucine (Ile)

2-30

2-14

3-11

3-17

Leucine (Leu)

14-72

9-25

8-23

10-53

Phenylalanine (Phe)

9-49

7-18

5-18

8-23

Tryptophan (Trp)

<14

<14

<14

<14

Allo-isoleucine (AlloIle)

<2

<2

<2

<2

 

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

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 that affect amino acid transport and metabolism 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 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.

 

Cerebrospinal fluid (CSF) specimens are highly informative for a subset of these conditions, such as nonketotic hyperglycinemia and serine biosynthesis defects. CSF specimens are most informative when a plasma specimen is collected at the same time, and the ratio of the amino acid concentrations in CSF to those in plasma is calculated.

Interpretation

When no significant abnormalities are detected, a simple descriptive interpretation is provided. When abnormal results are detected, a detailed interpretation is provided. This interpretation includes 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 the telephone number to reach one of the laboratory directors in case the referring physician has additional questions.

Cautions

Proper specimen collection and handling are crucial to achieve reliable results.

 

Blood contamination can interfere with test results.

Clinical Reference

1. Rinaldo P, Hahn S, Matern D. Inborn errors of amino acid, organic acid, and fatty acid metabolism. In: Burtis CA, Ashwood ER, Bruns DE. Tietz Textbook of Clinical Chemistry and Molecular Diagnosis. 4th ed. WB Saunders Company; 2005:2207-2247

2. Van Hove JLK, Coughlin C II, Swanson M, et al. Nonketotic hyperglycinemia. In: Adam MP, Feldman J, Mirzaa GM, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2002. Updated May 23, 2019. Accessed October 24, 2024. Available at www.ncbi.nlm.nih.gov/books/NBK1357/

3. El-Hattab AW. Serine biosynthesis and transport defects. Mol Genet Metab. 2016;118(3):153-159. doi:10.1016/j.ymgme.2016.04.010

4. 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 (AA) 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

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Testing Algorithm

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

 

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

NY State Approved

Yes

Method Name

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

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