Skip Ribbon Commands
Skip to main content
Sign In

24794 Cystine, Quant, 24 Hour Urine (CYSQN)

Cystine, Quant, 24 Hour Urine (CYSQN)
Test Code: CYSTSO
Synonyms/Keywords
Amino Acid, Cystine, Quantitative, Urine, Cystinuria
Useful For
Diagnosis of cystinuria
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
24-Hour Urine​ ​Plastic, 10 mL urine tube ​5 mL 1 mL​
Collection Processing Instructions
1. Collect before intravenous pyelogram.
2. Collect urine for 24 hours.
3. Add 20 mL of toluene as preservative at start of collection. If toluene is not available, refrigerate during collection.
4. Mix well before taking 5-mL aliquot.
Additional Information:
1. 24-Hour volume is required.
Specimen Stability Information
Specimen Type Temperature Time
​Urine ​ ​Frozen (preferred) ​70 days
Refrigerated ​ ​14 days
Rejection Criteria

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

Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Friday​ ​3 to 5 days
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)​
Reference Lab
Test Information

Cystinuria is an inborn error of metabolism resulting from poor absorption and reabsorption of the amino acid cystine in the intestines and kidneys. This leads to an accumulation of poorly soluble cystine in the urine and results in the production of kidney stones (urolithiasis). Symptoms may include acute episodes of abdominal or lower back pain, presence of blood in the urine (hematuria), and recurrent episodes of kidney stones may result in frequent urinary tract infections, which may ultimately result in renal insufficiency. The combined incidence of cystinuria has been estimated to be 1 in 7000.

Cystinuria is an autosomal recessive disease, but some heterozygous carriers have an autosomal dominant, incomplete penetrance appearance with elevated, but typically nondisease causing, urinary cystine excretion. Cystinuria is caused by variants in genes, SLC3A1 on chromosome 2p and SLC7A9 on chromosome 19q. Initially, the disease was classified into subtypes I, II, and III (type II and III are also referred as nontype-I) based on the amount of urinary cystine excreted in heterozygous parental specimens. A new classification system has been proposed to distinguish the various forms of cystinuria: type A, due to variants in the SLC3A1 gene; type B, due to variants in the SLC7A9 gene; and type AB, due to 1 variant in each SLC3A1 and SLC7A9 gene.

Reference Range Information
CYSTINE
3-15 years: 11-53 mcmol/24 hours
> or =16 years: 28-115 mcmol/24 hours
 
LYSINE
3-15 years: 19-140 mcmol/24 hours
> or =16 years: 32-290 mcmol/24 hours
 
ORNITHINE
3-15 years: 3-16 mcmol/24 hours
> or =16 years: 5-70 mcmol/24 hours
 
ARGININE
3-15 years: 10-25 mcmol/24 hours
> or =16 years: 13-64 mcmol/24 hours
 
Conversion Formulas:
Result in mcmol/24 hours x 0.24=result in mg/24 hours
Result in mg/24 hours x 4.17=result in mcmol/24 hours
Interpretation

Homozygotes or compound heterozygotes with 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 nontype 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.

Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​82136
Synonyms/Keywords
Amino Acid, Cystine, Quantitative, Urine, Cystinuria
Ordering Applications
Ordering Application Description
​Centricity ​Cystine, Qnt, 24H Urine (8376)
​Cerner ​Cystine 24 Hour Urine (8376)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
24-Hour Urine​ ​Plastic, 10 mL urine tube ​5 mL 1 mL​
Collection Processing
1. Collect before intravenous pyelogram.
2. Collect urine for 24 hours.
3. Add 20 mL of toluene as preservative at start of collection. If toluene is not available, refrigerate during collection.
4. Mix well before taking 5-mL aliquot.
Additional Information:
1. 24-Hour volume is required.
Specimen Stability Information
Specimen Type Temperature Time
​Urine ​ ​Frozen (preferred) ​70 days
Refrigerated ​ ​14 days
Rejection Criteria

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

Useful For
Diagnosis of cystinuria
Reference Range Information
CYSTINE
3-15 years: 11-53 mcmol/24 hours
> or =16 years: 28-115 mcmol/24 hours
 
LYSINE
3-15 years: 19-140 mcmol/24 hours
> or =16 years: 32-290 mcmol/24 hours
 
ORNITHINE
3-15 years: 3-16 mcmol/24 hours
> or =16 years: 5-70 mcmol/24 hours
 
ARGININE
3-15 years: 10-25 mcmol/24 hours
> or =16 years: 13-64 mcmol/24 hours
 
Conversion Formulas:
Result in mcmol/24 hours x 0.24=result in mg/24 hours
Result in mg/24 hours x 4.17=result in mcmol/24 hours
Interpretation

Homozygotes or compound heterozygotes with 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 nontype 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.

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Friday​ ​3 to 5 days
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​82136
For most current information refer to the Marshfield Laboratory online reference manual.