Urine tests for Down's syndrome screening

Background There are few publications on search strategies to identify diagnostic test accuracy (DTA) studies in lilacs. Objective To translate and customise medline search strategies for use in lilacs and assess their retrieval of studies in Cochrane DTA systematic reviews. Method We developed a six‐step process to translate and customise medline search strategies for use in lilacs (iAHx interface). We identified medline search strategies of published Cochrane DTA reviews, translated/customised them for use in lilacs, ran searches in lilacs and compared the retrieval results of our translated search strategy versus the one used in the published reviews. Results Our lilacs search strategies translated/customised from the medline strategies retrieved studies in 70 Cochrane DTA reviews. Only 29 of these reviews stated that they had searched the lilacs database and 21 published their lilacs search strategies. Few had used the lilacs database search tools, none exploded the subject headings, and 86% used only English terms. Conclusion Translating and tailoring a medline search strategy for the lilacs database resulted in the retrieval of DTA studies that would have been missed otherwise.

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“…(), 59 Alldred, Deeks, Guo, Neilson and Alfirevic (), 60 Alldred et al. (), 61 Alldred et al. (), 62 Soares‐Weiser et al.…”

Section: Resultsunclassified

lilacs search strategy for systematic reviews of diagnostic test accuracy studies

Pereira

Puga

Atallah

et al. 2019

Health Info Libraries J

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“…There is a paucity of evidence available to support the use of urine testing for Down's syndrome screening in clinical practice where alternatives are available. 13 Alldred SK et al reported that meta-analysis of the six most frequently evaluated test combinations showed that a test strategy involving maternal age and a combination of first trimester NT and PAPP-A, and second trimester total hcG, uE3, AFP and Inhibin A significantly outperformed other test combinations that involved only one serum marker or NT in the first trimester, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate. 14 Alldred SK et al reported that meta-analysis of 12 best performing or frequently evaluated test combinations showed double and triple tests (involving AFP, uE3, total hcG, free hcG) significantly outperform individual markers, detecting six to seven out of every 10 Down's syndrome pregnancies at a 5% false positive rate.…”

Section: Resultsmentioning

confidence: 99%

Antenatal screening for aneuploidy

Patne¹,

Upadhye

Shembekar

et al. 2017

Int J Reprod Contracept Obstet Gynecol

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Background: It is uncertain how best to screen pregnant women for the presence of fetal Down's syndrome and other aneuploides, whether to perform first-trimester screening or to perform second-trimester screening or both.Methods: Women with singleton and multiple pregnancies underwent first-trimester combined screening (measurement of nuchal translucency, pregnancy-associated plasma protein A [PAPP-A], and the free beta subunit of human chorionic gonadotropin at 10 weeks 3 days through 13 weeks 6 days of gestation). Also, second-trimester quadruple screening (measurement of alpha-fetoprotein, total human chorionic gonadotropin, unconjugated estriol, and inhibin A) and triple marker test was done from 15 to 18 weeks of gestation.Results: 12 (5%) patients had positive screening test for combined screening in first trimester, 6 (10.9%) patients had positive screening for quadruple test while 1 (2.85%) patients had positive screening for triple test. Out of 19 positive screening, 16 (84.21%) had their amniocentesis done for confirmation of diagnosis. In all 16 patients, chromosomal analysis was normal. Not a single patient turned out to have a baby with Down syndrome or any other aneuploidy. False positive rate for combined screening in first trimester was 5%, false positive rate for quadruple test in second trimester was 10.9%, false positive rate for triple marker test in second trimester was 2.85%.Conclusions: First-trimester combined screening is better than second-trimester quadruple test or triple marker test for syndrome or any other aneuploidy.

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“…Thus, the levels found in urine will be in luenced by maternal blood levels and the different metabolic rates of the molecules will be re lected in our analysis. This has not been fully appreciated when urinary marker tests for Downs Syndrome screen have been evaluated previously [25]. The m/z bin centile distribution plots make no assumption as to the normality of distribution of the data; which for each group, and at each m/z, could be Gaussian but are frequently skewed.…”

Section: Gestational Age Correctionmentioning

confidence: 99%

The importance of gestational age in first trimester, maternal urine MALDI-Tof MS screening tests for Down Syndrome

Iles¹,

Nicolaides²,

Pais³

et al. 2019

Ann Proteom Bioinform

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Background: The proposal that MALDI-ToF mass spectrometry could be used as a direct, rapid and affordable diagnostic tool in clinical laboratory medicine has moved from a theoretical possibility to a reality for Microbiology. Several studies have proposed the application of this technology in obstetric and gynaecological evaluation of patients. In particular, we have proposed that the adoption of MALDI-ToF mass spectrometry in examination of maternal pregnancy urine samples for the detection of Downs syndrome. Methods: A retrospective collection of 20 Down Syndrome and 100 non-aneuploid pregnancy urines at 12 to 14 weeks gestation, collected in 2007-2008 from high risk pregnancy cohorts, were examined by MALDI-ToF mass spectrometry in the mass/charge range between 1000 and 100000 m/z. Normalisation of spectral data was defi ned using mass bins of 100 m/z expressed as a percentage of the total ion count of the mass spectra from 2000 to 11000 m/z. Of the ninety 100 m/z bins, forty-six were identifi ed as m/z bins at which statistically signifi cant differences in spectra occurred between Downs and control/non-aneuploid samples. Based on the differences and variance, for values at these bins, weighted scores of the probability of being Downs were assigned. Comparative algorithms consisting of various mass bins were tested for ability to distinguish Down syndrome from non-aneuploid pregnancy. Results: Although various algorithms could distinguish Downs from non-aneuploid controls, it was found that gestational age was a confounding factor and that if separated into gestational age matched cohorts the ability to distinguish the groups improved dramatically e.g. whilst a 19 bins algorithm separated 100% of Downs from non-aneuploid pregnancies for a 9% false positive rate in the mixed gestational ages group; a two bin algorithm distinguished 100% of Downs for a 6% false positive rate for the 12 weeks gestational age pregnancies. Conclusion: Normalised MALDI-ToF mass spectra, at 2000 to 11000 m/z, of maternal urine gives rise to gestational age specifi c screening tests algorithms for Downs's syndrome. The importance of gestational age in fi rst trimester, maternal urine MALDI-Tof MS screening tests for Down Syndrome

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Urine tests for Down's syndrome screening

Cited by 7 publications

References 456 publications

lilacs search strategy for systematic reviews of diagnostic test accuracy studies

lilacs search strategy for systematic reviews of diagnostic test accuracy studies

Antenatal screening for aneuploidy

The importance of gestational age in first trimester, maternal urine MALDI-Tof MS screening tests for Down Syndrome

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