First-trimester screening for trisomy 21 using alpha-fetoprotein (original) (raw)
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Prospective validation of first-trimester combined screening for trisomy 21
Ultrasound in Obstetrics and Gynecology, 2009
Objective To examine the performance of the new algorithm in screening for trisomy 21 by a combination of maternal age, fetal nuchal translucency (NT) and maternal serum free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A).
Ultrasound in Obstetrics & Gynecology, 2012
ObjectiveTo prospectively evaluate the performance of first‐trimester combined screening for trisomy 21 using the biochemical markers pregnancy‐associated plasma protein‐A (PAPP‐A) and free beta‐human chorionic gonadotropin (free β‐hCG) obtained before and at the time of the nuchal translucency (NT) scan.MethodsThree fetal medicine departments in Denmark participated in the study. Screening for trisomy 21 was set up as a two‐step approach with blood sampling performed before the NT scan (early sample) and again at the time of the NT scan (late sample). PAPP‐A and free β‐hCG were measured on both the early and late samples. Age‐standardized detection and false‐positive rates for different screening protocols were calculated.ResultsWe collected two blood samples in 27 pregnancies affected by trisomy 21 and in 3891 control pregnancies. The early samples were taken between gestational ages 8 + 0 and 13 + 6 weeks, and the late samples between 11 + 3 and 14 + 6 weeks. The median interval ...
First Trimester Biochemical Screening for Trisomy 21
Annals of Clinical Biochemistry: An international journal of biochemistry and laboratory medicine, 1995
The potential efficacy of screening for trisomy 21 in the first trimester, using maternal serum markers 01 fetoprotein, free fJ human chorionic gonadotropin, unconjugated oestriol and pregnancy associated plasma protein A, was studied in an unselected population of women between the seventh and fourteenth week of gestation. Using a combination of 01 fetoprotein and free fJ human chorionic
Influence of first trimester biochemistry methodology on detection rate in screening for trisomy 21
Ginekologia Polska, 2017
Objectives: The purpose of the study was to compare detection rates (DR) of FMF-certified and non-certified biochemical tests (BC) in trisomy 21 screening at 11-13 + 6 weeks. Material and methods: In 2267 singleton pregnancies FMF-certified doctors measured crown to rump length (CRL) and nuchal translucency (NT). Serum samples were tested for free β-hCG and the PAPP-A using 2 analysers (Delfia-Perkin Elmer and Immulite 2000-DPC), the results were expressed in MoM values and used for computer calculation of the risk for trisomy 21. The cutoff value for the high trisomy 21 risk was 1:300. Results: Comparison of free β-hCG MoMs by DPC and Delfia demonstrated statistically significant differences in normal, and trisomy 21 fetuses respectively. Similarly, statistically significant differences were noted for PAPP-A MoMs. The above differences in MoMs resulted in altered sensitivity in screening for aneuploidy. The application of the FMF-certified method ensures a markedly higher DR = 74%, compared to non-certified tests (64%), both at 5% FPR. The ROC analysis was performed in order to assess the efficacy of both tests. Results of trisomy 21 BC + NT risk scales using the Delfia and DPC methods are highly significant (p < 0.0001), which means that their discrimination ability is > 90%. The difference between results obtained using the Delfia and DPC methods is AUC = 0.0150 and is statistically significant (Z = 2.4728, p = 0.0134). Conclusions: The use of FMF-certified first trimester biochemistry analysers improves DR for trisomy 21. The use of non-certified analysers causes reduction of DR and an increase of invasive procedure rate.
Ultrasound in Obstetrics & Gynecology, 2013
Objective To define risk cut-offs with corresponding detection rates (DR) and false-positive rates (FPR) in screening for trisomy 21 using maternal age and combinations of first-trimester biomarkers in order to determine which women should undergo contingent maternal blood cell-free (cf) DNA testing. (DV-PIV) at 11 + 0 to 13 + 6 weeks' gestation and serum free β-human chorionic gonadotropin (β-hCG), pregnancy-associated plasma protein-A (PAPP-A), placental growth factor (PlGF) and alpha-fetoprotein (AFP) at 8 + 0 to 13 + 6 weeks. Estimates of risk cutoffs, DRs and FPRs were derived for combinations of biomarkers and these were used to define the best strategy for contingent cfDNA testing.
Single-Step Maternal Serum Screening for Trisomy 21 in the Era of Combined or Integrated Screening
Gynecologic and Obstetric Investigation, 2004
Single-step maternal serum screening (MSS) in the first (1MSS) or second (2MSS) trimester at maternal age 635 years was evaluated in the North Belgian region Flanders, where difficulties are encountered in the general introduction of combined or integrated screening algorithms. The fetal aneuploidy screening database of General Medical Laboratory AML in Antwerp was searched for 2MSS tests between 1992 and 1999 (·-fetoprotein, ßhuman chorionic gonadotropin (ß-HCG) and unconjugated estriol, cut-off 1:300) and for 1MSS tests between 1999 and 2003 (free ß-HCG and pregnancy-associated plasma protein A, cut-off 1:85). At 635 years, the detection rate for trisomy 21 (DR) was 93.8% (15/16) for 2MSS and the screen-positive rate (SPR) was 24.5% (504/2061). For 1MSS, these figures were 85.7% (6/7) and 17.7% (109/615) respectively. To detect one trisomy 21, missed by MSS at 635 years of age, an additional number of 1,557 and 506 primary invasive procedures would be needed for 2MMS and 1MSS respectively. We conclude that the performance of both single-step 1MSS and 2MSS at maternal age 635 years in Flanders is excellent, even without the combination with ultrasound parameters or integration of first and second trimester parameters. The simplicity of both methods allows to consider them valuable options for fetal aneuploidy screening at advanced maternal age, until high quality combined or integrated screening is accessible to all pregnant women in Belgium.