| Median parameters for Down's syndrome screening should be calculated using a moving time-window method. | |
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MedLine Citation:
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PMID: 18768535 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: In Down's syndrome screening, the change in analyte concentrations in maternal serum with advancing gestational age is compensated for by converting concentration to multiples of the median (MoM) by using a mathematical equation describing the expected relationship. However, owing to assay drifts and shift, the equation may be incorrect, leading to deviation of the observed MoM distribution from the ideal MoM distribution. The NHS Fetal Anomaly Screening Programme has produced standards limiting acceptable deviation, and has provided the Down's Syndrome Screening Quality Assurance Service (DQASS) to monitor it. DQASS recommends monitoring by cumulative sum plot. METHODS: Down's screening data for 61,368 consecutive samples (12 October 2004 to 31 December 2007) was evaluated using different median assignment techniques. RESULTS: A change in the paradigm for median equation derivation is described, which significantly improves the probability that medians will be correct at any point in time. CONCLUSION: Software developers need to change the way medians are derived in their programmes. |
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Authors:
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T M Reynolds; J Aldis |
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Publication Detail:
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Type: Journal Article Date: 2008-09-03 |
Journal Detail:
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Title: Annals of clinical biochemistry Volume: 45 ISSN: 0004-5632 ISO Abbreviation: Ann. Clin. Biochem. Publication Date: 2008 Nov |
Date Detail:
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Created Date: 2008-10-22 Completed Date: 2009-02-04 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0324055 Medline TA: Ann Clin Biochem Country: England |
Other Details:
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Languages: eng Pagination: 567-70 Citation Subset: IM |
Affiliation:
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Clinical Chemistry Department, Queen's Hospital, Belvedere Road, Burton-on-Trent, Staffordshire DE13 0RB. Tim.Reynolds@Burtonh-tr.wmids.nhs.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Biological Markers
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blood Chorionic Gonadotropin, beta Subunit, Human / blood Down Syndrome / blood*, diagnosis* Estriol / blood Female Gestational Age Humans Maternal-Fetal Exchange Pregnancy Prenatal Diagnosis / methods*, standards, statistics & numerical data Quality Control alpha-Fetoproteins / analysis |
| Chemical | |
Reg. No./Substance:
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0/Biological Markers; 0/Chorionic Gonadotropin, beta Subunit, Human; 0/alpha-Fetoproteins; 50-27-1/Estriol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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