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Objectives: The objective of this study is to identify the optimal cut-off points of contingent serum screening excluding nuchal translucency (NT) measurement, to categorize the risk level in the first trimester.Methods: A prospective database of women undergoing contingent serum screening, without NT measurement, was reviewed. In conventional categorization, the results of first-trimester screening were categorized into high risk (>1:30) (invasive diagnosis was offered); intermediate risk (1:30-1:1500) (second-trimester screening was needed); and low risk (<1:1500) (no further test). We recategorized the risk levels using various upper and lower cut-offs and compared detection rates, false-positive rates, and rates of intermediate risk.Results: Among 24,874 women, the prevalence of Down syndrome was 1:691. The previously agreed cut-offs had a detection rate of 88.9% and a false-positive rate of 8.5% with high rate of intermediate risk (38.2%). Re-categorization provided the optimal lower and upper cut-offs 1/900 and 1/50, respectively, giving a detection rate of 86.1%, a false-positive rate of 8.1%, and a rate of intermediate risk of 24.8%.Conclusions: This is the first study on contingent serum screening without NT measurement which shows a high detection rate with an acceptable false-positive rate. The optimal cut-offs to categorize the risk levels of the upper and the lower cut-off was 1:30-1:50 and 1:900, respectively. [ABSTRACT FROM AUTHOR]

Objective: Prenatal screening with cell-free DNA (cfDNA) offers improved detection of Down syndrome (T21) compared to conventional screening. These tests are expensive and have fewer detectable anomalies. Our objective was to investigate potential costs and test performance of screening algorithms when accounting for detectable aneuploidies.Methods: This is a cost analysis for a large military treatment facility. Using a theoretical delivery cohort and published performance data, universal screening with cfDNA was compared to sequential screening, comparing T21 to all detectable aneuploidies. Predicted test performance and costs were calculated.Results: A cohort of 3000 deliveries was used. For T21, universal cfDNA is more expensive ($1,346,064) than sequential screening ($244,885), but has a lower false positive rate and avoids 101 invasive diagnostic tests. An additional case of T21 is detected with a marginal cost of $1,101,179. For all detectable aneuploidies, cfDNA is more expensive ($1,353,660) than sequential screening ($239,189), and 59 invasive diagnostic tests are avoided. Sequential screening detects an additional case of aneuploidy, with a cost savings of $1,114,471.Conclusions: Although cfDNA is superior in detecting T21 cases, sequential screening is superior when considering all aneuploidies detectable. The cost increase with universal cfDNA is significant, and is not justified with small improvements in the performance. [ABSTRACT FROM AUTHOR]

Objective: To report the strategy of first-trimester aneuploidy screening in pregnancies at risk for homozygous α(0)-thalassemian.Methods: Women at risk of homozygous α(0)-thalassemia were given an ultrasound examination at 11-14 weeks' gestation to exclude an affected pregnancy. Fetal cardiothoracic ratio (CTR) and nuchal translucence (NT) were measured. If cardiomegaly was found, chorionic villus sampling (CVS) was offered for α-thalassemia; otherwise the first-trimester combined screening test was performed on the pregnancy. The invasive testing for karyotyping was only followed in those cases with a positive aneuploidy screening test.Results: In total, 69 of 288 pregnancies were found to be affected by homozygous α(0)-thalassemia using ultrasound, and the findings were confirmed by invasive testing. In the remaining 219 pregnancies, invasive testing was not performed for α-thalassemia because of a normal fetal CTR, and the women received the first-trimester combined screening. Nine CVS procedures were performed for karyotyping because of a positive aneuploidy screening. Totally three pregnancies with aneuploidy were diagnosed and terminated.Conclusions: Our strategy can selectively detect aneuploidy pregnancies not affected by homozygous α-thalassemia, and, meanwhile, save on the cost of unnecessary aneuploidy screening or karyotyping in pregnancies with an affected fetus of homozygous α(0)-thalassemia. [ABSTRACT FROM AUTHOR]