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Test Code CYSR Cystinuria Profile, Quantitative, Random, Urine

Reporting Name

Cystinuria Profile, QN, Random

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Biochemical diagnosis of cystinuria using random urine specimens

Method Name

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


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


Supplies: Urine Tubes, 10 mL (T068)

Specimen Volume: 2 mL

Collection Instructions: Collect a random urine specimen.


Specimen Type

Urine

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 70 days
  Refrigerated  14 days

Reject Due To

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

Reference Values

Amino Acid

Age groups

<2 months

2-35 months

3-6 years

7-17 years

≥18 years

Arginine

Arg

<250

<147

<81

<42

<65

Ornithine

Orn

<344

<238

<228

<291

<193

Cystine

Cys

<486

<285

<111

<84

<142

Lysine

Lys

<2217

<1321

<814

<463

<295

 

All results reported as nmol/mg creatinine.

Interpretation

Individuals who are homozygous or compound heterozygous for cystinuria excrete large amounts of cystine in urine, but the amount varies markedly. Urinary excretion of other dibasic amino acids (arginine, lysine, and ornithine) is also typically elevated. Plasma concentrations are generally normal or slightly decreased.

 

Individuals who are homozygous and heterozygous for non-type I cystinuria can be distinguished by the pattern of urinary amino acids excretion: homozygous individuals secrete large amounts of cystine and all 3 dibasic amino acids, whereas heterozygous individuals secrete more lysine and cystine than arginine and ornithine.

Day(s) Performed

Monday through Friday

Report Available

3 to 5 days

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

82136

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CYSR Cystinuria Profile, QN, Random 90784-0

 

Result ID Test Result Name Result LOINC Value
23517 Arginine 30062-4
23516 Ornithine 30049-1
23514 Cystine 30065-7
23515 Lysine 30048-3
50416 Reviewed By 18771-6