Age-Independent Indices in Second-Trimester Serum Screening for Down's Syndrome Are Useless

Zimmermann, Roland; Reynolds, Tim; John, Rhys; Spencer, Kevin; Bartels, Iris; Coombes, E J; Trevor, Susan C

doi:10.1002/(sici)1097-0223(199601)16:1<79::aid-pd811>3.0.co;2-4

Cited by 3 publications

(1 citation statement)

References 4 publications

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“…Analogous to Zimmerman et al (1996), who stressed that age-independent indices in secondtrimester serum screening for DS are useless, we showed that it is useless to discuss developments in DS screening performance without explicitly taking into account the demographic characteristics of the population under consideration. The implication of our results for the 15 European countries is that each country may have its own pathways to implement a serum screening programme for the prevention of DS in the population.…”

Section: Discussionmentioning

confidence: 57%

A Demographic Approach to the Assessment of Down Syndrome Screening Performance

et al. 1997

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Section: Discussionmentioning

confidence: 57%

A Demographic Approach to the Assessment of Down Syndrome Screening Performance

et al. 1997

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Atypicality or Specific Screen: Which is Better at Detecting Non-Down's Chromosomal Anomalies?

Reynolds

1997

Ann Clin Biochem

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I evaluated the value of adding a trisomy 18 screen to routine Down's screening and compared it with the benefits of atypicality screening. I studied 5080 unaffected pregnancies, 144 Down's syndrome and 190 non-Down's syndrome chromosome abnormalities (20 trisomy 13; 79 trisomy 18; 20 Turner's syndrome; 29 other sex chromosome abnormalities; 8 triploidy; and 34 miscellaneous). Using a one in 250 cut off, the Down's screen gave a screen positive rate of 4.07%; addition of atypicality without a trisomy 18 screen gave an extra 0.9% screen positives; trisomy 18 screening without atypicality gave an extra 0.51% screen positives; and atypicality screening after trisomy 18 screening gave 0.52% screen positives. Total screen positive rates were: Down's screening only, 4.07%; Down's screening + atypicality, 4.97%; Down's screening + trisomy 18 screen, 4.58%; Down's screening + trisomy 18 screen + atypicality, 5.09%. The detection rate for Down's syndrome using a one in 250 cut off was 58.9% and with addition of trisomy 18 and atypicality screening this increased to 59.3%, indicating that the extra screens add little to detection of Down's syndrome. For the other chromosomal abnormalities, Down's screening alone detected 22.6% of cases overall and addition of trisomy 18 and atypicality screening increased this to 49%. Examination of the marginal benefits of the extra screening tests revealed that the trisomy 18 screen was better at detecting chromosomal abnormalities than the Down's screen and that it would, therefore, be worthwhile adding this to all screening programs. Atypicality proved to be much less effective and it is suggested that this screen should only be applied in the early days of a screening program until sufficient data is available to design specific screens.

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Development and Characterization of Antibodies to a Nicked and Hyperglycosylated Form of hCG from a Choriocarcinoma Patient: Generation of Antibodies That Differentiate Between Pregnancy hCG and Choriocarcinoma hCG

Birken

Krichevsky

O’Connor

et al. 1999

ENDO

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Human chorionic gonadotropin (hCG) exists in blood and urine as a variety of isoforms one of which contains peptide bond cleavages within its beta-subunit loop 2 and is referred to as nicked hCG (hCGn). This hCG isoform appears to be more prevalent in the urine of patients with certain malignancies and possibly in some disorders of pregnancy. Until now, only indirect immunoassays could be used to quantify hCGn. We report the development of two monoclonal antibodies (MAbs) to a form of hCGn isolated from a choriocarcinoma patient. This hCG isoform was not only 100% nicked, but also contained 100% tetrasaccharide-core O-linked carbohydrate moieties in its beta COOH-terminal region. Two-site immunometric assays have been developed using these new antibodies, B151 and B152. The former exhibits good specificity for hCGn independent of the source of the hCGn, the form excreted by choriocarcinoma patients or the form of hCGn from normal pregnancies. The latter antibody, B152, is sensitive to the carbohydrate moieties and possibly other differences in hCG isoforms, but is not for nicking of the beta-subunit. These two immunometric assays provide potential novel diagnostic tools for direct measurement of hCG isoforms which could not be accurately quantified earlier before development of the assays using these newly generated antibodies.

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Age-Independent Indices in Second-Trimester Serum Screening for Down's Syndrome Are Useless

Cited by 3 publications

References 4 publications

A Demographic Approach to the Assessment of Down Syndrome Screening Performance

A Demographic Approach to the Assessment of Down Syndrome Screening Performance

Atypicality or Specific Screen: Which is Better at Detecting Non-Down's Chromosomal Anomalies?

Development and Characterization of Antibodies to a Nicked and Hyperglycosylated Form of hCG from a Choriocarcinoma Patient: Generation of Antibodies That Differentiate Between Pregnancy hCG and Choriocarcinoma hCG

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