Changes in transferrin glycosylation during pregnancy may lead to false-positive carbohydrate-deficient transferrin (CDT) results in testing for riskful alcohol consumption.
BACKGROUND
An alcohol-induced change in serum transferrin glycosylation, termed carbohydrate-deficient transferrin (CDT), is widely used as a biomarker of heavy long-term drinking. This study examined the transferrin glycosylation profile and the risk for false-positive CDT results during pregnancy.


METHODS
Serum samples were collected from 24 healthy pregnant women starting in gestation week 9-21, throughout pregnancy, and 8 or more weeks after delivery. Altogether 171 sera (5-9 samples/person) were analysed. Transferrin glycoforms were quantified as a percentage of total transferrin, using an HPLC candidate reference method for CDT.


RESULTS
During pregnancy, the relative disialo-, pentasialo- and hexasialotransferrin levels increased gradually, whereas trisialo- and tetrasialotransferrin were reduced. This effect was most pronounced in the third trimester. For disialotransferrin, the main target in CDT testing, initial values of 1.07 ± 0.17% (mean ± SD) increased to 1.61 ± 0.23% before delivery (~50% increase). Nine (38%) pregnant women reached %disialotransferrin values ≥ 1.7% (97.5th percentile for controls) but all results were < 2.0%. In the postpartum samples, all glycoform levels had returned towards the starting values.


CONCLUSIONS
These results suggest that the cutoff for %disialotransferrin and %CDT employed to indicate heavy long-term drinking need to be raised slightly in pregnant women, to minimize the risk for false-positive results on CDT testing.
Kenan
Naama
N
Alcohol Laboratory, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
Larsson
Anders
A
Axelsson
Ove
O
Helander
Anders
A
D000328:Adult; D000428:Alcohol Drinking / Q000097:blood* / Q000378:metabolism; D001774:Blood Chemical Analysis / Q000379:methods / Q000592:standards*; D002851:Chromatography, High Pressure Liquid; D005189:False Positive Reactions; D005260:Female; D006031:Glycosylation; D006801:Humans; D049590:Postpartum Period / Q000097:blood / Q000378:metabolism; D011247:Pregnancy; D012015:Reference Standards; D012306:Risk; D014168:Transferrin / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D055815:Young Adult
D014168:Transferrin; C056759:carbohydrate-deficient transferrin