Combined first- and second-trimester screening for Down syndrome: an evaluation of proMBP as a marker.
OBJECTIVE
To estimate the screening performance of different combinations of first- and second-trimester markers, including a new marker, the proform of eosinophil major basic protein (proMBP).


METHODS
The population comprised 195 singleton pregnancies with a normal outcome enrolled in the Copenhagen First Trimester Study, in which a serum sample was available from both the first and the second trimester. The performance of different marker combinations was estimated by receiver-operator-characteristics (ROC) analysis using a Monte Carlo simulation and distributions of log(10)MoM markers and their correlations, derived from our normal material and Down syndrome cases from the literature.


RESULTS
Using a fixed screen-positive rate (SPR) of 5%, the first-trimester combined test [nuchal translucency (NT), PAPP-A and free beta-hCG] yielded a detection rate (DR) of 76%, and the integrated test (NT, PAPP-A, AFP, hCG, uE3 and inhibin A) yielded a DR of 86%. With a DR of 90%, the best combination was the first-trimester beta-hCG and NT with the second-trimester proMBP and AFP. ProMBP combined with the triple test increased the DR from 62 to 83%, whereas the addition of inhibin A only increased the DR to 69%.


CONCLUSIONS
These results suggest that proMBP may be an important new marker in Down syndrome screening and, in particular, a good substitute for inhibin A.
Rode
Line
L
Department of Obstetrics and Gynecology, Hvidovre University Hospital, Denmark.
Wøjdemann
Karen R
KR
Shalmi
Anne-Cathrine
AC
Larsen
Severin Olesen
SO
Sundberg
Karin
K
Nørgaard-Pedersen
Bent
B
Christiansen
Michael
M
Tabor
Ann
A
D000328:Adult; D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins; D004314:Down Syndrome / Q000097:blood* / Q000175:diagnosis* / Q000000981:diagnostic imaging; D047091:Eosinophil Granule Proteins; D005260:Female; D006801:Humans; D009010:Monte Carlo Method; D009333:Neck / Q000000981:diagnostic imaging / Q000196:embryology; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D012372:ROC Curve; D012260:Ribonucleases / Q000097:blood*; D014463:Ultrasonography
D015415:Biomarkers; D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D012260:Ribonucleases