NOTE: Another "transferrin index" is calculated from serum iron and transferrin levels (see above, under Iron).
Quantitation:
(1) isoelectric focusing followed by immunofixation
(2) microanion-exchange chromatography coupled with RIA
(3) isoelectric focusing followed by Western blotting
transferrin index =
= (pI 5.7 fraction on isoelectric focusing) / (pI 5.4 fraction)
Alternatively:
transferrin index =
= (serum carbohydrate deficient transferrin) / (total transferrin)
Interpretation:
• Active alcoholics have 5-10% of serum transferrin as carbohydrate deficient transferrin.
• Serum carbohydrate deficient transferrin may be elevated in patients drinking more than 50-80 grams of alcohol per day for at least 1 week.
• During abstinence the values decrease to normal slowly with a half-life of about 15-17 days.
Limitations:
• Not all active drinkers have elevations in carbohydrate deficient transferrin.
• Not all active drinkers have elevation in the transferrin index.
• Although usually not affected by liver disease, more experience is needed to determine possible impact of different hepatic conditions on serum levels.
