Alpha-fetoprotein in the early neonatal period--a large study and review of the literature.
BACKGROUND
Alpha-fetoprotein (AFP) is a glycoprotein molecule, which has similarity to albumin and is produced by the fetal liver. Its biological role is unclear and factors that may influence its concentrations in neonates are only partially identified. However, it has an important role as a diagnostic marker, especially in certain tumors and liver diseases of childhood. Its normal reference values in newborns have not been well defined.


METHODS
Serum AFP concentrations were measured and characterized in 260 term and near-term newborns [gestational age (GA)> or =34 weeks, birthweight (BW)> or =1700 g] at birth [umbilical cord (UC) blood] and upon discharge from the nursery at 60+/-24 h of life (venous sample).


RESULTS
Due to the nonnormal distribution of AFP levels, it is useful to relate to reference interval for AFP concentrations at birth that was 15.7-146.5 microg/ml, based on 95% confidence interval (CI). The median value of 48.3 microg/ml is also a useful reference. However, mean AFP concentrations at birth that were 61.6+/-44.8 microg/ml are less informative due to the large standard deviation (S.D.). Upon discharge, AFP concentrations dropped to 9.7-111.9 microg/ml (95% CI) with a median of 34.2 microg/ml. A significant negative correlation was found between AFP serum levels and gestational age and to a lesser extent with birthweight. No significant differences were found between males and females.


CONCLUSIONS
Normal reference intervals for AFP in term and near-term newborns have been defined, but need to be addressed with caution due to the wide range of normal values. AFP levels at birth decrease as gestation advances and the newborn weighs more.
Department of Neonatology, Bnai Zion Medical Center, The B. Rappaport Faculty of Medicine, Technion. Israel Institute of Technology, 47 Golomb Street, P.O.B. 4940, Haifa, Israel.
D
D
Bader
A
A
Riskin
O
O
Vafsi
A
A
Tamir
B
B
Peskin
N
N
Israel
R
R
Merksamer
H
H
Dar
M
M
David
D000328:Adult; D015415:Biomarkers; D001724:Birth Weight; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D012016:Reference Values; D012727:Sex Characteristics; D000509:alpha-Fetoproteins / Q000032:analysis / Q000378:metabolism*
D015415:Biomarkers; D000509:alpha-Fetoproteins