First trimester screening for Down's syndrome using maternal serum PAPP-A and free beta=hCG in combination with fetal nuchal translucency thickness (original) (raw)
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Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 2005
Background: Recent NICE Guidelines have emphasized the need to have in place by 2007 the capability of offering screening to all women in the first trimester using a combination of maternal age with the ultrasound marker nuchal translucency thickness (NT) and the maternal serum biochemical markers free β-hCG and pregnancy-associated plasma protein-A (PAPP-A). Laboratories will therefore need to consider how to introduce the biochemical component of screening. With the recent launch of these assays on the DPC Immulite 2000 platform, it is appropriate and timely to investigate their clinical and analytical performance on a high throughput immunoassay analyser. Methods: Within-run and between-day precision was assessed in the normal way. Bias was assessed by comparing samples from normal pregnancies ( n = 813) and pregnancies with Down's syndrome ( n = 60) run on both the DPC system and our routine Kryptor system. Gestational day-specific medians for each marker were calculated fro...
Serum screening for Down's syndrome between 8 and 14 weeks of pregnancy
BJOG: An International Journal of Obstetrics and Gynaecology, 1996
To determine the value of serum screening for Down's syndrome at 8-14 weeks of pregnancy using seven potential serum markers (alpha-fetoprotein, unconjugated oestriol, total human chorionic gonadotrophin (hCG), free a-hCG, free P-hCG, pregnancy associated plasma protein A (PAPP-A), and dimeric inhibin A). Design Stored blood samples collected from women at about 10 weeks of pregnancy, prior to having a chorionic villus sampling procedure on account of advanced maternal age, were retrieved from pregnancies associated with Down's syndrome and from matched unaffected pregnancies.
Clinica Chimica Acta, 1996
A low maternal serum concentration of pregnancy associated plasma protein-A (MS-PAPP-A) in the first trimester has been suggested as a marker for the presence of a Down's syndrome (DS) fetus. We developed a time-resolved immunofluorometric assay (TrlFMA) for PAPP-A with a sensitivity < 3.9 mlU/1. In the 7-12 gestational weeks interval the median multiples of the median (MoM) was 0.57 (95%-confidence interval: 0.47-0.99) in DS pregnancies (n = 29) and lower than in controls (n = 223) (P < 0.005). The efficiency of MS-PAPP-A alone was evaluated using empirical receiver-operator-characteristics (ROC) and a sensitivity of about 25% was found for a false-positive rate of about 10% in the 7-12 gestational weeks interval. In parameterized ROC analysis a sensitivity of 9% was found for a false-positive rate of 5%. The TrlFMA PAPP-A assay seems to fulfil the quality criteria for an assay to be used in large-scale serum screening for Down's syndrome.
Maternal serum screening for Down's syndrome in the first trimester of pregnancy
BJOG: An International Journal of Obstetrics and Gynaecology, 1995
Biochemical screening for Down's syndrome usually takes place in the second trimester of pregnancy. If effective maternal serum screening could be carried out in the first trimester, prenatal diagnosis using chorionic villous sampling (CVS) would allow for the identification of trisomy 21, and thus early pregnancy termination. Several studies have shown that alpha-fetoprotein and unconjugated oestriol (uE,) serum levels decrease in Down's syndrome pregnancies during the first trimester , while human chorionic gonadotrophin (hCG) levels are within the normal range ). In contrast with hCG, free PhCG subunit levels have been found to be increased significantly in first trimester maternal serum from Down's syndrome pregnancies .
2002
Background: The acceptability of prenatal screening and diagnosis of Down syndrome is dependent, in part, on the gestational age at which the testing is offered. First trimester screening could be advantageous if it has sufficient efficacy and can be effectively delivered. Issues: Two first trimester maternal serum screening markers, pregnancy-associated plasma protein-A (PAPP-A) and free h-human chorionic gonadotropin (h-hCG), are useful for identifying women at increased risk for fetal Down syndrome. In addition, measurement of an enlarged thickness of the subcutaneous fluid-filled space at the back of the neck of the developing fetus (referred to as nuchal translucency or NT) has been demonstrated to be an indicator for these high-risk pregnancies. When these three parameters are combined, estimates for Down syndrome efficacy exceed those currently attainable in the second trimester. Women who are screen-positive in the first trimester can elect to receive cytogenetic testing of ...
2002
BACKGROUND The acceptability of prenatal screening and diagnosis of Down syndrome is dependent, in part, on the gestational age at which the testing is offered. First trimester screening could be advantageous if it has sufficient efficacy and can be effectively delivered. ISSUES Two first trimester maternal serum screening markers, pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (beta-hCG), are useful for identifying women at increased risk for fetal Down syndrome. In addition, measurement of an enlarged thickness of the subcutaneous fluid-filled space at the back of the neck of the developing fetus (referred to as nuchal translucency or NT) has been demonstrated to be an indicator for these high-risk pregnancies. When these three parameters are combined, estimates for Down syndrome efficacy exceed those currently attainable in the second trimester. Women who are screen-positive in the first trimester can elect to receive cytogenetic testing...
Down’s Syndrome Screening in the First Trimester with Additional Serum Markers: Indian Parameters
The Journal of Obstetrics and Gynecology of India
Objective To derive a risk calculation algorithm suitable for use in India when screening for Down's syndrome using four first-trimester maternal serum markers either alone or with ultrasound nuchal translucency (NT). Methods Stored maternal serum samples (-20°C) from 411 singleton unaffected pregnancies were retrieved and measured for pregnancy-associated plasma protein (PAPP-A), free b-human chorionic gonadotropin (hCG), placental growth factor and a-fetoprotein. Samples were taken at
A prospective two years study of first trimester screening for Down syndrome
Hippokratia, 2008
Nowadays maternal age of pregnant women has increased in most developed countries. The rate of women above 35 years old constitutes about 15% of pregnancies. The aim of our study is to prove that by first trimester screening, the number of women who have indication for invasive prenatal diagnostic procedure is significantly reduced. This prospective study lasted two years from 02/2005 to 02/2007. The participants to our study were 531 pregnant women with a mean maternal age of 30 years (19-42). We used the first trimester screening test for Down's syndrome. The biochemical blood test of free b-hCG (beta human chorionic gonadotropin) and PAPP-A (pregnancy associated plasma protein A) and the measurement of nuchal translucency were performed between 11-13 weeks +6 days (mean gestational age 12 weeks +2 days). In our study group, 69 women (12%) were 35 years old or more. The risk estimate for Down syndrome was 1 in 300 or more in 14 (2%) cases. In all these 14 cases we offered CVS ...