Carbohydrate Deficient Transferrin (CDT)

Description: 
CDT measured by capillary electrophoresis.
Clinical details: 
Transferrin produced in the liver is post-translationally modified with the addition of a number of sialic acid side-chains. This process is controlled by two groups of enzymes, glucuronyl transferases which add the side-chains and sialidase which removes them. In a normal individual the majority of transferrin in the circulation has between three and five sialic acid groups. It was found that in subjects abusing alcohol there is a significant increase in the proportion of transferrin with fewer sialic acid side-chains. Carbohydrate deficient transferrin (CDT) is considered to be the group of transferrins having no side-chains (asialo), one (mono-sialo) and two (di-sialo). In normal subjects CDT comprises less than 1.6% of the total transferrin concentration. Excess alcohol intake significantly increases this percentage and the increase is independent of the presence of liver disease; alcohol appearing to affect the above mentioned enzyme systems directly. Drugs that induce GGT (e.g. anti-convulsants etc.) have no effect on CDT and it can, therefore, be used in the presence of such drugs. The relationship between %CDT and units of alcohol consumed is good, although less strong in pre-menopausal women than in men or post-menopausal women. Rare diseases of glycosylation (CDG syndromes) and the D variant of transferrin found in a small percentage of African subjects could theoretically cause false positive results.
Reference range: 

CDT < or = 1.5% : No excess alcohol intake CDT 1.6-1.9% : Intake may be high but not necessarily in the range of dependence CDT > or = 2.0% : Excess alcohol intake

Units: 
%
Sample type and Volume required: 
Serum (500 µL).
Turnaround time: 
6 working days
Storage and transport: 
Stable at 4°C for up to one week. Send by overnight first class post.
Contacts:
Reference Biochemistry Department at King's College Hospital
020 3299 4107
King's College Hospital
Denmark Hill
London SE5 9RS
Metabolic Laboratory at King's College Hospital
020 3299 4128
King's College Hospital
Denmark Hill
London SE5 9RS
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 21/12/2016