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Order Code OLIGU Oligosaccharide Screen, Random, Urine

Useful For

Screening for selected oligosaccharidosis

Method Name

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)

Reporting Name

Oligosaccharide Screen, U

Specimen Type

Urine


Ordering Guidance


This is the recommended test when clinical features are suggestive of, or when molecular testing results suggest, an oligosaccharidosis disorder that can be identified by this test.

 

The recommended screening test for the initial workup of a suspected lysosomal storage disorder, particularly when clinical features are nonspecific, is LSDS / Lysosomal Storage Disorders Screen, Random, Urine.



Necessary Information


1. Patient's age is required.

2. Biochemical Genetics Patient Information (T602) is recommended. This information aids in providing a more thorough interpretation of results. Send information with specimen.



Specimen Required


Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 8 mL

Pediatric Volume: 2 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative

3. Immediately freeze specimen.


Specimen Minimum Volume

2.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 365 days
  Refrigerated  15 days
  Ambient  7 days

Reject Due To

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

Reference Values

An interpretive report will be provided.

Method Description

Urine samples are extracted using Oasis HLB and carbograph columns and lyophilized overnight. Oligosaccharides are permethylated, replacing all hydroxy groups (-OH) with methoxy groups (-OCH3) and esterifies carboxyl groups (-COOH to -COOCH3). After permethylation, the tubes are centrifuged, and the supernatant removed from the sodium hydroxide pellet. The supernatant is quenched, neutralized, extracted onto an Oasis HLB column, eluted, and lyophilized again overnight. Specimens are resuspended, mixed with a matrix solution containing 2,5-dihydroxybenzoic acid, spotted onto a MALDI plate, and allowed to air dry. The plate is then analyzed using a matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI TOF/TOF) 5800 Analyzer.(Xia B, Asif G, Arthur L, et al. Oligosaccharide analysis in urine by MALDI-TOF mass spectrometry for the diagnosis of lysosomal storage diseases. Clin Chem. 2013;59[9]:1357-1368, Hall PL, Lam C, Alexander JJ. Urine oligosaccharide screening by MALDI-TOF for the identification of NGLY1 deficiency. Mol Genet Metab. 2018;124[1]:82-86)

Day(s) Performed

Monday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

84377

Testing Algorithm

Oligosaccharide analysis may be considered in the workup of unexplained refractory epilepsy. For more information see:

-Epilepsy: Unexplained Refractory and/or Familial Testing Algorithm

-Congenital Disorders of Glycosylation: Screening Algorithm

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.

Genetics Test Information

Oligosaccharidoses are characterized by the abnormal accumulation of incompletely degraded oligosaccharides in cells and tissues and the corresponding increase of related free oligosaccharides in the urine.

 

Clinical features of the oligosaccharidoses often overlap; therefore, urine screening is an important tool in the initial workup for these disorders.

 

Enzyme or molecular analysis is required to make a definitive diagnosis.