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HelpTest Code SORDB Sorbitol and Xylitol, Quantitative, Whole Blood
Ordering Guidance
This is a test for diagnosis and treatment monitoring for sorbitol dehydrogenase deficiency-related peripheral neuropathy.
Necessary Information
Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.
Specimen Required
Patient Preparation:
Fasting: 8 hours, required
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Green top (sodium heparin)
Specimen Volume: 1 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Freeze whole blood specimens in the original tube. Frozen aliquots from well-mixed specimens are also acceptable.
3. Send frozen.
Forms
Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.
Useful For
Screening and treatment monitoring for sorbitol dehydrogenase deficiency-related neuropathy.
Genetics Test Information
This test is used to aid in the diagnosis and treatment monitoring of patients with sorbitol dehydrogenase-related peripheral neuropathy.
Method Name
Gas Chromatography Mass Spectrometry (GC-MS) Stable Isotope Dilution Analysis
Reporting Name
Sorbitol and Xylitol, QN, WBSpecimen Type
Whole bloodSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole blood | Frozen (preferred) | 90 days |
| Refrigerated | 31 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
Sorbitol dehydrogenase (SORD) deficiency is an autosomal recessive condition caused by biallelic variants in the SORD gene resulting in peripheral neuropathy, which may present as clinically similar to Charcot-Marie-Tooth disease type 2 or distal hereditary motor neuropathy. The SORD enzyme catalyzes the breakdown of sorbitol to fructose. In patients with SORD deficiency-related peripheral neuropathy, two urine polyols, sorbitol and xylitol, are elevated in both blood and urine when compared to controls. Polyols are sugar alcohols that have been identified in blood, urine, and cerebrospinal fluid. An abnormal blood and urine polyol result suggestive of SORD deficiency-related peripheral neuropathy should be confirmed with molecular genetic analysis. For molecular confirmation, genetic testing for SORD can be performed (CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify gene list ID: NEUROLOGY-S3NL4H).
Reference Values
Sorbitol: ≤15.0 nmol/mL
Xylitol: ≤2.0 nmol/mL
Day(s) Performed
Friday
Report Available
5 to 11 daysSpecimen Retention Time
3 monthsPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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
82542
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SORDB | Sorbitol and Xylitol, QN, WB | In Process |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 623504 | Interpretation | 59462-2 |
| 623502 | Sorbitol | In Process |
| 623503 | Xylitol | In Process |
| 623505 | Reviewed By | 18771-6 |