S-Sulfocysteine, Urine
Test Mnemonic
USULFC
CPT Codes
- 82570 - QTY (1)
- 82131 - QTY (1)
LOINC ®
34168-5
Aliases
- Isolated Sulfite Oxidase Deficiency
- Molybdenum Cofactor Deficiency
Performing Laboratory
Duke University Hospital
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Urine, random | Clean container (No preservatives) | Frozen | Ship frozen on dry ice. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 0.25 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Frozen | 7 months |
| Refrigerated | 15 days |
| Ambient | 15 days |
Days Performed
1 day per week
Turnaround Time
7 - 10 days
Methodology
| Name | Description |
|---|---|
| Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) |
Special Info
Refrigerate or freeze ASAP after collection.
Clinical Info
S-Sulfocysteine affected range: (n=6; mean +/- 2 SD): 200 - 2000 umol/g creatinine. S-Sulfocysteine is a disease-specific metabolite that accumulates in patients with Molybdenum cofactor deficiency (MoCoD) and isolated sulfite oxidase deficiency (ISOD). Determination of this metabolite in urine provides a reliable indication of MoCoD or ISOD deficiency. This ESI-MS/MS method is much preferred over the use of sulfite dipstick tests that are only of utility if urine is fresh because sulfite is rapidly oxidized to sulfate at room temperature. Also, the dipstick test lacks specificity and has been reported to give both false positive and negative results. The S-Sulfocysteine assay should be considered in the work up of individuals with neonatal seizures.