Prospective evaluation of free beta-subunit of human chorionic gonadotropin and dimeric inhibin A for aneuploidy detection.
OBJECTIVE
Our goal was to prospectively evaluate the use of the free beta-subunit of human chorionic gonadotropin and dimeric inhibin A for the detection of fetal Down syndrome and other aneuploidies.


METHODS
Women who had a second-trimester multiple-marker screening test (alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin) and genetic amniocentesis from August 1996 to August 1998 were included. Serum was also analyzed for inhibin and the free beta-subunit of human chorionic gonadotropin. Detection and false-positive rates for 4 analyte combinations at 5 different screening risk cutoff points for Down syndrome were determined and compared.


RESULTS
We evaluated 1256 patients, including 23 with aneuploidy (13 with Down syndrome, 10 others). The maternal age was 35.9 +/- 4.6 years (mean +/- SD). At the optimal risk cutoff point for Down syndrome detection (1:190; false-positive rate, 19%), the multiple-marker screening test plus inhibin was superior, detecting 85% of Down syndrome cases, in comparison with 69% when the multiple-marker screening test alone was used and 62% when the other 2 combinations were used. The multiple-marker screening test plus inhibin also detected 60% of the other aneuploidies.


CONCLUSIONS
When evaluated prospectively in a high-risk population, the multiple-marker screening test plus inhibin was superior to the traditional multiple-marker screening test and 2 other analyte combinations, with a lower false-positive rate and increased detection of all aneuploidies in a high-risk population.
Wenstrom
K D
KD
Center for Obstetric Research, Department of Obstetrics and Gynecology, The University of Alabama at Birmingham, USA.
Owen
J
J
Chu
D c
Dc
Boots
L
L
D000649:Amniocentesis; D000782:Aneuploidy; D006063:Chorionic Gonadotropin / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D019281:Dimerization; D004314:Down Syndrome / Q000175:diagnosis; D004964:Estriol / Q000097:blood; D005189:False Positive Reactions; D005260:Female; D017353:Gene Deletion; D006801:Humans; D007265:Inhibins / Q000097:blood*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D011446:Prospective Studies; D014178:Translocation, Genetic; D014314:Trisomy; D000509:alpha-Fetoproteins / Q000032:analysis
D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D000509:alpha-Fetoproteins; D007265:Inhibins; D004964:Estriol