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HelpTest Code CYSQN Cystinuria Profile, Quantitative, 24 Hour, Urine
Reporting Name
Cystinuria Profile, QN, 24 hourUseful For
Diagnosis of cystinuria using 24-hour urine collections
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineNecessary Information
1. 24-Hour volume (in milliliters) is required.
2. Patient's age is required.
3. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.
Specimen Required
-Urine Tubes, 10 mL (T068)
-Diazolidinyl Urea (Germall) 5.0 mL (T822)
Specimen Volume: 5 mL
Collection Instructions:
1. Collect before intravenous pyelogram.
2. Add 5 g of diazolidinyl urea (Germall) as preservative at start of collection. If preservative is not available, refrigerate during collection.
3. Collect urine for 24 hours.
4. Mix well before taking 5-mL aliquot.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Frozen (preferred) | 70 days | |
| Refrigerated | 14 days |
Special Instructions
Reference Values
Cystine
3-15 years: ≤53 mcmol/24 h
≥16 years: ≤115 mcmol/24 h
Lysine
3-15 years: ≤140 mcmol/24 h
≥16 years: ≤290 mcmol/24 h
Ornithine
3-15 years: ≤16 mcmol/24 h
≥16 years: ≤70 mcmol/24 h
Arginine
3-15 years: ≤25 mcmol/24 h
≥16 years: ≤64 mcmol/24 h
Conversion Formulas:
Result in mcmol/24 hours x 0.24 =result in mg/24 h
Result in mg/24 hours x 4.17 =result in mcmol/24 h
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
82136
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CYSQN | Cystinuria Profile, QN, 24 hour | 90785-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TM38 | Collection Duration | 13362-9 |
| VL36 | Urine Volume | 3167-4 |
| 3583 | Cystine | 13966-7 |
| 3589 | Lysine | 25464-9 |
| 3590 | Ornithine | 25491-2 |
| 3591 | Arginine | 25322-9 |
| 50447 | Reviewed By | 18771-6 |
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.
Clinical Reference
1. Servais A, Thomas K, Strologo LD, et al. Cystinuria: clinical practice recommendation. Kidney Int. 2021;99(1):48-58
2. Palacin M, Goodyer P, Nunes V, Gasparini P. Cystinuria. 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/content.aspx?bookid=2709§ionid=225555540
Report Available
3 to 5 daysMethod Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.