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HelpTest Code CHOU Carbohydrate, Urine
Reporting Name
Carbohydrate, UPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Screening for conditions associated with increased excretion of carbohydrates, including inborn errors of fructose and galactose metabolism.
This test is not recommended as a follow up test for abnormal newborn screening for galactosemia.
Method Name
Gas Chromatography Mass Spectrometry (GC-MS)
Ordering Guidance
This test is a quantitative analysis of carbohydrate excretion in the urine. It is not appropriate for evaluation of an abnormal newborn screen for galactosemia. For those cases, order GCT / Galactosemia Reflex, Blood and consider GAL1P / Galactose-1-Phosphate, Erythrocytes and GATOL / Galactitol, Quantitative, Urine.
Necessary Information
Patient's age is required.
Specimen Required
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 5 mL
Collection Instructions:
1. Collect an early-morning (preferred) random urine specimen.
2. No preservative.
Specimen Type
UrineSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Frozen | 42 days |
Reject Due To
| Urine containing preservatives | Reject |
Reference Values
Reducing Substances: Negative
Quantitative results are reported as mmol/mol creatinine.
|
Age range |
<12 months |
12 months-18 years |
≥19 years |
|
Xylose |
≤13 |
≤38 |
≤9 |
|
Fructose |
≤32 |
≤31 |
≤16 |
|
Galactose |
≤117 |
≤32 |
≤5 |
|
Glucose |
≤139 |
≤15 |
≤22 |
|
Sucrose |
≤27 |
≤46 |
≤20 |
|
Lactose |
≤160 |
≤18 |
≤5 |
|
Maltose |
≤5 |
≤1 |
≤2 |
|
Raffinose |
≤1 |
≤1 |
≤1 |
Interpretation
When abnormal results are detected, a detailed interpretation is given, including an overview of the results and of their significance, a correlation to available clinical information, elements of differential diagnosis, recommendations, if any, for additional biochemical testing, and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.
Day(s) Performed
Tuesday
Report Available
3 to 9 daysTest 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
84379
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CHOU | Carbohydrate, U | 74447-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 622708 | Interpretation | 59462-2 |
| 622709 | Reducing Substances | 5809-9 |
| 622710 | Xylose | 75051-3 |
| 622711 | Fructose | 34309-5 |
| 622712 | Galactose | 25102-5 |
| 622713 | Glucose | 34312-9 |
| 622714 | Sucrose | 76132-0 |
| 622715 | Lactose | 74438-3 |
| 622716 | Maltose | 74895-4 |
| 622717 | Raffinose | 48147-3 |
| 622744 | Reviewed By | 18771-6 |
Forms
Testing Algorithm
Qualitative testing for the presence of reducing substances is performed followed by quantitative analysis of carbohydrates including fructose, galactose, xylose, glucose, sucrose, lactose, maltose, and raffinose.