TRIPLE TEST – THE SCREENING OF FETAL CHROMOSOMAL
ANEUPLOIDIES AND OPEN NEURAL TUBE DEFECTS IN CENTRAL POLAND
Perenc
M, Kaluzewski B, Bodalski J
Clinic of Pediatrics, Medical
University of Lodz, Poland
Objective: Triple test is a biochemical screening for fetal
trisomy 21 and open neural tube defects performed in the second trimester
of pregnancy.
Methods: The study was performed in the period from 1997 to 2000
and comprised the group of 2010 pregnant women from central Poland. a-fetoprotein, total b-hCG and
unconjugated estriol concentrations were determined in maternal sera
between 14th and 21st week of gestation (ultrasound
dating). The individual risks of fetal trisomy and open neural tube defects
were calculated using PRISCA 3.0 software. Ulm Index was also calculated
for each patient. The studied group consisted of 24 women with fetal
aneuploidies, 12 women with fetal open NTD and 1974 women with healthy
fetuses.
Results: Triple test characterized the sensitivity 93% and
specificity 81% using PRISCA 3.0 software at cut-off level 1:250. The false
positive rate for Ulm Index did not correlate with maternal age and equaled
5% at the cut-off value of 8,1, the sensitivity of Ulm Index was 68%. In
the group of other fetal aneuploidies 2 cases of fetal trisomy 13, 2 cases
of fetal trisomy 18, 1 case of Klinefelter syndrome and 1 case of Turner
syndrome were detected using PRISCA 3.0 software which originally is
adapted to fetal trisomy 21. In this group only 2 cases of fetal trisomy 18
were detected using Ulm Index. In 11 cases of fetal open NTD maternal serum
AFP levels were above 2,5 MoM, yielding the sensitivity of 92% at the
specificity of 96%.
Conclusions:
Triple
test using PRISCA 3.0 software
can detect fetal trisomy 21 (cut-off 1:250) and fetal open neural tube
defects as well as other chromosomal aneuploidies e.g. trisomy 13, trisomy
18, Turner and Kline felter syndrome.