Search results for "False Positive Reaction"
showing 7 items of 37 documents
Prenatal Ultrasound Screening: False Positive Soft Markers May Alter Maternal Representations and Mother-Infant Interaction
2012
Background In up to 5% of pregnancies, ultrasound screening detects a “soft marker” (SM) that places the foetus at risk for a severe abnormality. In most cases, prenatal diagnostic work-up rules out a severe defect. We aimed to study the effects of false positive SM on maternal emotional status, maternal representations of the infant, and mother-infant interaction. Methodology and Principal Findings Utilizing an extreme-case prospective case control design, we selected from a group of 244 women undergoing ultrasound, 19 pregnant women whose foetus had a positive SM screening and a reassuring diagnostic work up, and 19 controls without SM matched for age and education. In the third trimester…
Detection of Human Immunodeficiency Virus-1 Nucleic Acid on Inactivated Filter Paper Disks by Polymerase Chain Reaction and Microtiter Plate Assay
1994
Human immunodeficiency virus type 1 (HIV-1) in cultured cells, peripheral blood samples and sera were adsorbed on filter paper disks and inactivated by heat or ethanol. Two procedures, the polymerase chain reaction (PCR) and microtiter plate assay (HMPA) were used to detect the nucleic acid. The sensitivity after different heat treatments with nested PCR for HIV-1 DNA (or nested reverse transcription-PCR for HIV-1 RNA) was identical regardless of whether the samples were examined immediately or one month later. Inactivation by ethanol treatment resulted in a slight loss of sensitivity. The HMPA proved to be as reliable and specific as the conventional PCR technique. We conclude that the hea…
Bloodstains on Leather: Examination of False Negatives in Presumptive Test and Human Hemoglobin Test.
2017
Presumptive tests for blood are very simple and sensitive tests used in the search for evidence. They also provide initial information on the nature of stains. A second test can confirm their nature. However, these tests can present false–negative results for different reasons. Some of those reasons have been studied, while others, those caused by the substrate material that contains the stain, are less well known. This work studies the effect of one component of a leather substrate—quebracho extract—on presumptive and human hemoglobin blood tests. Assays were performed using samples of blood dilutions contaminated with quebracho extract and others formed on a substrate containing the conta…
Lead-time and overdiagnosis estimation in neuroblastoma screening.
2003
In Germany, neuroblastoma is the most frequent extracranial solid childhood tumour. Its properties made it seem an ideal candidate for screening. A German trial assessed the effect of screening at one year of age from 1995-2001 in a nationwide project. We present here the methods developed for the estimation of lead-time and overdiagnosis in this project. Follow up on 1.5 million screened children and 2.1 million control children is currently available until June 2002. Ascertainment of control cohort cases and false negative cases is complete up to this date. A method for determining an empirical lead-time distribution and overdiagnosis estimate from comparing the age specific incidences in…
Long-term prediction of birth weight
1993
On the basis of the hypothesis that undisturbed individual growth in fetal life keeps a constant proportional difference with the standard population 50th percentile, birth weight can be predicted with a single sonographic exploration after the 16th week of pregnancy. Data on 135 singleton pregnancies with accurate dates and delivery at term were used. Sonography was performed between the 17th and 36th weeks of pregnancy, in every case at least 4 weeks before delivery. The observed measurements of BPD, FL, and AC were used for the prediction of their values on the day of delivery, applying the Hadlock equation for the estimation of birth weight. The mean error of birth weight predictions wa…
Additive effect of factors related to assisted conception on the reduction of maternal serum pregnancy-associated plasma protein A concentrations and…
2013
Objective To analyze whether assisted conceptions need adjustments in first-trimester Down syndrome screening and why modifications in screening markers occur. Design Eleven-year cohort retrospective analysis. Setting Maternal-fetal medicine unit. Patient(s) Two thousand eleven naturally conceived normal singleton pregnancies and 2,042 normal singleton pregnancies achieved with assisted conception: 350 by IUI and 1,692 with IVF (n = 328) or intracytoplasmic sperm injection (ICSI; n=1,364), using nondonor (n = 1,086) or donated ova (n = 606), with fresh (n = 1,432) or frozen (n = 260) embryos. Intervention(s) Comparison of ultrasound and biochemical markers of first-trimester Down syndrome s…
Diagnostic efficacy of the fluorometric determination of enzyme activity for Pompe disease from dried blood specimens compared with lymphocytes-possi…
2009
Pompe disease is a rare, autosomal-recessive disorder which results from a defect in the lysosomal enzyme acid alpha-glucosidase (GAA). The onset of this disease is highly variable, with infantile types being the most severe. Traditionally, lymphocytes, fibroblasts or muscle biopsies were necessary for enzyme activity measurement, because these materials do not express maltase-glucoamylase (MGA) that interferes with the assay. Recently, acarbose was found to inhibit MGA activity selectively, so that dried blood became accessible for GAA assessment.To evaluate the diagnostic efficacy of GAA measurement in dried blood specimens (DBSs) in comparison with lymphocytes. If DBSs provided reliable …