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HelpTest Code SAU Sialic Acid, Free and Total, Random, Urine
Ordering Guidance
This is a recommended screening test for patients suspected to have a diagnosis of free sialic acid storage disease.
Urine oligosaccharides are also recommended for patients with a suspected diagnosis of sialidosis or galactosialidosis.
Necessary Information
Patient's age is required.
Specimen Required
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Container/Tube: Plastic, 5-mL urine tube
Specimen Volume: 1 mL
Pediatric Volume: 0.5 mL
Collection Instructions: Collect a random urine specimen (early morning preferred).
Forms
1. Biochemical Genetics Patient Information (T602)
2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Useful For
Screening for sialic acid disorders
Special Instructions
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Sialic Acid, Free and Total, USpecimen Type
UrineSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 90 days | |
| Frozen | 90 days |
Reference Values
Free Sialic Acid:
≤4 weeks: ≤208 mmol/mol creatinine
5 weeks-12 months: ≤104 mmol/mol creatinine
13 months-18 years: ≤100 mmol/mol creatinine
≥19 years: ≤38 mmol/mol creatinine
Total Sialic Acid
≤4 weeks: ≤852 mmol/mol creatinine
5 weeks-12 months: ≤656 mmol/mol creatinine
13 months-18 years: ≤335 mmol/mol creatinine
≥19 years: ≤262 mmol/mol creatinine
Total/Free Ratio:
≤4 weeks: 1.94-18.68
5 weeks-12 months: 2.34-13.85
13 months-18 years: 2.63-9.18
≥19 years: 3.35-15.81
An interpretive report will also be provided.
Interpretation
An elevated result of total/free sialic acid ratio may be indicative of sialidosis or galactosialidosis.
A decreased result of total/free sialic acid ratio may be indicative of free sialic acid storage disorder.
Abnormal results or clinical suspicion should be confirmed with biochemical or molecular genetic analysis.
Clinical Reference
1.Adams D, Wasserstein M. Free Sialic Acid Storage Disorders. In: Adam MP, Mirzaa GM, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle;1993-2023. Updated January 23, 2020. Accessed May 22, 2023.Available at: www.ncbi.nlm.nih.gov/books/NBK1470/
2. Huizing M, Hackbarth ME, Adams DR, et al. Free sialic acid storage disorder: Progress and promise. Neurosci Lett. 2021;755:135896. doi:10.1016/j.neulet.2021.135896
3. Khan A, Sergi C. Sialidosis: A review of morphology and molecular biology of a rare pediatric disorder. Diagnostics (Basel). 2018;8(2):29. Published 2018 Apr 25. doi:10.3390/diagnostics8020029
4. Annunziata I, d'Azzo A. Galactosialidosis: historic aspects and overview of investigated and emerging treatment options. Expert Opin Orphan Drugs. 2017;5(2):131-141. doi:10.1080/21678707.2016.1266933
Day(s) Performed
Friday
Report Available
5 to 11 daysPerforming 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
84275
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SAU | Sialic Acid, Free and Total, U | 104657-2 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 621069 | Free Sialic Acid | 104658-0 |
| 621070 | Total Sialic Acid | 104659-8 |
| 621071 | Total/Free Sialic Acid Ratio | 104660-6 |
| 621072 | Interpretation | 94423-1 |
| 621073 | Reviewed By | 18771-6 |