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Test Code CDT Carbohydrate Deficient Transferrin for Congenital Disorders of Glycosylation, Serum

Reporting Name

CDG, S

Useful For

Screening for congenital disorders of glycosylation


Advisory Information


This test is for congenital disorders of glycosylation. If the ordering physician is looking for evaluation of alcohol abuse, order CDTA / Carbohydrate Deficient Transferrin, Adult, Serum.



Necessary Information


1. Patient's age is required.

2. Reason for referral is required.



Specimen Required


Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.1 mL


Seattle Children's Hospital Note:

Collect 0.5 mL whole blood in a Red or Gold Top.

Specimen Type

Serum

Specimen Minimum Volume

0.05 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Frozen (preferred) 45 days
  Refrigerated  28 days
  Ambient  7 days

Day(s) and Time(s) Performed

Monday, Thursday; 8 a.m.

Seattle Children's Hospital Note:

TAT: 7 - 12 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name

Affinity Chromatography-Mass Spectrometry (MS)

Method Description

Samples are prepared by diluting serum in water. The sample is injected into an immunoaffinity column and washed. Following 2 wash steps, proteins are then eluted and introduced into an API 4000 tandem mass spectrometer equipped with a Turbo V source configured for electrospray ionization. The mass spectrometer is operated in positive Q1 scan mode with 2 scan ranges; m/z 1090-2000 for apolipoprotein CIII and m/z 2000-3000 for transferrin. Relative quantitation of carbohydrate deficient transferrin and apolipoprotein CIII is achieved by comparing glycoform ratios in each protein.(Lacey JM, Bergen R, Magera MJ, et al: Rapid determination of transferrin isoforms by immunoaffinity liquid chromatography and electrospray mass spectrometry. Clin Chem 2001;47:513-518)

Reference Values

Ratio

Normal

Indeterminate

Abnormal

Transferrin Mono-oligo/Di-oligo Ratio

≤0.06

0.07-0.09

≥0.10

Transferrin A-oligo/Di-oligo Ratio

≤0.011

0.012-0.021

≥0.022

Transferrin Tri-sialo/Di-oligo Ratio

≤0.05

0.06-0.12

≥0.13

Apo CIII-1/Apo CIII-2 Ratio

≤2.91

2.92-3.68

≥3.69

Apo CIII-0/Apo CIII-2 Ratio

≤0.48

0.49-0.68

≥0.69

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82373

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CDG CDG, S 53803-3

 

Result ID Test Result Name Result LOINC Value
BG160 Reason for Referral 42349-1
31721 Mono-oligo/Di-oligo Ratio 35469-6
31720 A-oligo/Di-oligo Ratio 35475-3
34474 Tri-sialo/Di-oligo Ratio In Process
34476 Apo CIII-1/Apo CIII-2 Ratio In Process
34475 Apo CIII-0/Apo CIII-2 Ratio In Process
50820 Interpretation 53808-2
50822 Reviewed By 18771-6

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross OK

Icterus

Mild OK; Gross OK

Other

NA

Forms

1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

2. Biochemical Genetics Patient Information (T602) in Special Instructions.