Comparison between Enzyme Immunoassays Performed on Samples of Dried Blood and Serum for Toxoplasmosis Prenatal Screening: Population-based Study

Abstract Objective Most prenatal screening programs for toxoplasmosis use immunoassays in serum samples of pregnant women. Few studies assess the accuracy of screening tests in dried blood spots, which are of easy collection, storage, and transportation. The goals of the present study are to determine the performance and evaluate the agreement between an immunoassay of dried blood spots and a reference test in the serum of pregnant women from a population-based prenatal screening program for toxoplasmosis in Brazil. Methods A cross-sectional study was performed to compare the immunoassays Imunoscreen Toxoplasmose IgM and Imunoscreen Toxoplasmose IgG (Mbiolog Diagnósticos, Ltda., Contagem, Minas Gerais, Brazil)in dried blood spots with the enzyme-linked fluorescent assay (ELFA, BioMérieux S.A., Lyon, France) reference standard in the serum of pregnant women from Minas Gerais Congenital Toxoplasmosis Control Program. Results The dried blood spot test was able to discriminate positive and negative results of pregnant women when compared with the reference test, with an accuracy of 98.2% for immunoglobulin G (IgG), and of 95.8% for immunoglobulin M (IgM). Conclusion Dried blood samples are easy to collect, store, and transport, and they have a good performance, making this a promising method for prenatal toxoplasmosis screening programs in countries with continental dimensions, limited resources, and a high prevalence of toxoplasmosis, as is the case of Brazil.

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Assessing Quality and Functionality of DNA from Fresh and Archival Dried Blood Spots and Recommendations for Quality Control Guidelines

Clinical Chemistry ◽

10.1373/clinchem.2007.087510 ◽

2007 ◽

Vol 53 (8) ◽

pp. 1401-1407 ◽

Cited By ~ 40

Author(s):

Malin Ida Linnea Sjöholm ◽

Joakim Dillner ◽

Joyce Carlson

Keyword(s):

Dna Extraction ◽

Multiple Displacement Amplification ◽

Dried Blood Spots ◽

Extraction Methods ◽

Population Based ◽

Alkaline Lysis ◽

Screening Programs ◽

Blood Spots ◽

Dna Yield ◽

Chelex 100

Abstract Background: Dried blood spots (DBS) are a convenient and inexpensive method for biobanking. Although many countries have established population-based DBS biobanks from neonatal screening programs, the quality and usefulness of DNA from DBS have not been extensively assessed. Methods: We compared 4 common DNA extraction methods (Qiagen, EZNA, Chelex 100, and alkaline lysis) in a pilot study using fresh DBS with known lymphocyte count. We assessed suitability for multiple displacement amplification (MDA) and subsequent single-nucleotide polymorphism (SNP) analyses. We selected the EZNA method for DNA extraction from archival samples up to 27 years old, stored at room temperature or −20 °C, and SNP analyses were performed after MDA. Results: Extraction using alkaline lysis failed in most tests, and Chelex 100 was unsuccessful in real-time PCR, whereas the EZNA and Qiagen methods were successful by all evaluated quality indices. DNA extraction by EZNA, MDA, and SNP analyses were successful for the archival samples stored at −20 °C. Conclusion: Routine protocols for evaluation of the quality and functional integrity of DNA based on DNA yield, DNA size, and quantification of amplifiable DNA allow use of sufficient template for MDA and successful SNP analyses from both primary DBS extract and MDA product. A single 3-mm disc can yield sufficient DNA for several thousand SNP analyses. DNA from DBS is thus suitable for genetic epidemiology studies.

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Population-based retrieval of newborn dried blood spots for researching paediatric cancer susceptibility genes

Paediatric and Perinatal Epidemiology ◽

10.1111/j.1365-3016.2006.00749.x ◽

2006 ◽

Vol 20 (5) ◽

pp. 449-452 ◽

Cited By ~ 10

Author(s):

Judith Klotz ◽

Patricia Bryant ◽

Homer B. Wilcox ◽

Mary Dillon ◽

Bruce Wolf ◽

...

Keyword(s):

Cancer Susceptibility ◽

Dried Blood Spots ◽

Population Based ◽

Susceptibility Genes ◽

Paediatric Cancer ◽

Blood Spots ◽

Cancer Susceptibility Genes

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Non-invasive colorectal cancer screening

University of Western Ontario Medical Journal ◽

10.5206/uwomj.v85i2.2231 ◽

2016 ◽

Vol 85 (2) ◽

pp. 29-31

Author(s):

Melissa Holdren ◽

Brittany Deller ◽

Kevin Braden

Keyword(s):

Colorectal Cancer ◽

Developmental Process ◽

Population Based ◽

Adenomatous Polyps ◽

Morbidity And Mortality ◽

Screening Tests ◽

Average Risk ◽

Screening Programs ◽

Asymptomatic Patients ◽

Advanced Adenomas

Colorectal cancer (CRC) is a major cause of morbidity and mortality throughout the world and is the second most common cause of Canadian cancer-related deaths in men and the third most common in women. Most CRC appears to arise from the gradual development and advancement of colonic adenomatous polyps to cancerous tissue. This developmental process of CRC is the rationale for screening programs which aim to reduce CRC-related morbidity and mortality by early detection and removal of adenomatous polyps, specifically advanced adenomas. Although both the gFOBT and FIT function to detect occult bleeding in asymptomatic patients at average risk for CRC development, the mechanisms of these screening tests are distinct. gFOBT works by detecting the peroxidase activity of heme whereas FIT selectively detects human hemoglobin. The sensitivity in detecting CRC is higher for the FIT, with sensitivity of 0.79 compared to gFOBT with sensitivity of 0.36, they have similar specificities of 0.94 and 0.96, respectively. Currently, both the gFOBT and FIT are strongly recommended across Canada, with all provinces using the FIT, apart from Ontario and Manitoba which currently use the gFOBT to screen asymptomatic patients for CRC. A newer test, the sDNA test, identifies mutations in DNA that are shed by both adenomatous polyps and CRC cells. The sDNA test is more sensitive (0.92 95% CI 0.83-0.98) than both the gFOBT and FIT, however, is less specific and more expensive. Further data surrounding the sDNA test will be required prior to its implementation and recommendation for population based CRC screening in Canada.

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Spectrophotometric Microassay for δ-Aminolevulinate Dehydratase in Dried-Blood Spots as Confirmation for Hereditary Tyrosinemia Type I

Clinical Chemistry ◽

10.1093/clinchem/47.8.1424 ◽

2001 ◽

Vol 47 (8) ◽

pp. 1424-1429 ◽

Cited By ~ 30

Author(s):

Andreas Schulze ◽

David Frommhold ◽

Georg F Hoffmann ◽

Ertan Mayatepek

Keyword(s):

Enzyme Activity ◽

Neonatal Screening ◽

Dried Blood Spots ◽

Confirmatory Test ◽

Type I ◽

Screening Programs ◽

Blood Spots ◽

Tyrosinemia Type I ◽

Aminolevulinate Dehydratase ◽

Hereditary Tyrosinemia

Abstract Background: Hereditary tyrosinemia type I (HT) fulfills the criteria for inclusion in neonatal screening programs, but measurement of tyrosine lacks clinical specificity and quantitative assay of succinylacetone is laborious. We developed a semiquantitative assay based on inhibition of δ-aminolevulinate dehydratase (ALA-D) by succinylacetone. Methods: Preincubation of 3-mm discs from dried-blood spots and reaction of the enzyme with δ-aminolevulinic acid as substrate were performed in microtiter plates. After separation of the supernatant and 10 min of color reaction with modified Ehrlich reagent, the formation of porphobilinogen was measured at 550 nm in a plate reader. Results: The detection limit for succinylacetone was 0.3 μmol/L; imprecision (CV) was <5.5% within-run and 10–16% between-run. Storage of blood spots at ambient temperature for several days led to a significant decrease of ALA-D activity. Enzyme activity was lost in filter cards at 45 °C, but remained stable at 2–37 °C. Enzyme activity was decreased in EDTA blood. The absorbance at 550 nm was 0.221 (± 0.073) in healthy neonates and 0.043–0.100 in 11 patients with HT. All neonates with increased tyrosine (above the 99.5th centile) in neonatal screening (97 of 47 000) had normal results by the new assay. Conclusions: The spectrophotometric microassay for ALA-D is a simple and sensitive test for HT. This represents a basis for further examination of its general reliability as a confirmatory test if tyrosine is found to be increased.

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Cervical Cancer Screening Programs in Europe: The Transition Towards HPV Vaccination and Population-Based HPV Testing

Viruses ◽

10.3390/v10120729 ◽

2018 ◽

Vol 10 (12) ◽

pp. 729 ◽

Cited By ~ 42

Author(s):

Andreas Chrysostomou ◽

Dora Stylianou ◽

Anastasia Constantinidou ◽

Leondios Kostrikis

Keyword(s):

Cervical Cancer ◽

Cancer Screening ◽

Cervical Cancer Screening ◽

Hpv Vaccination ◽

Screening Method ◽

Population Based ◽

Screening Tests ◽

Screening Methods ◽

Hpv Testing ◽

Screening Programs

Cervical cancer is the fourth most frequently occurring cancer in women around the world and can affect them during their reproductive years. Since the development of the Papanicolaou (Pap) test, screening has been essential in identifying cervical cancer at a treatable stage. With the identification of the human papillomavirus (HPV) as the causative agent of essentially all cervical cancer cases, HPV molecular screening tests and HPV vaccines for primary prevention against the virus have been developed. Accordingly, comparative studies were designed to assess the performance of cervical cancer screening methods in order to devise the best screening strategy possible. This review critically assesses the current cervical cancer screening methods as well as the implementation of HPV vaccination in Europe. The most recent European Guidelines and recommendations for organized population-based programs with HPV testing as the primary screening method are also presented. Lastly, the current landscape of cervical cancer screening programs is assessed for both European Union member states and some associated countries, in regard to the transition towards population-based screening programs with primary HPV testing.

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Identifying occult maternal malignancies from 1.93 million pregnant women undergoing noninvasive prenatal screening tests

Genetics in Medicine ◽

10.1038/s41436-019-0510-5 ◽

2019 ◽

Vol 21 (10) ◽

pp. 2293-2302 ◽

Cited By ~ 6

Author(s):

Xing Ji ◽

Jia Li ◽

Yonghua Huang ◽

Pi-Lin Sung ◽

Yuying Yuan ◽

...

Keyword(s):

Pregnant Women ◽

Prenatal Screening ◽

Screening Tests ◽

Noninvasive Prenatal Screening

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Compelling Choices: Tensions in the Practice and Experience of Prenatal Screening in New Zealand

10.26686/wgtn.17009750.v1 ◽

2021 ◽

Author(s):

◽

Sarah Ellen Donovan

Keyword(s):

Health Policy ◽

New Zealand ◽

Pregnant Women ◽

Prenatal Screening ◽

Risk Groups ◽

Population Based ◽

Ethical Practice ◽

Policy Makers ◽

Pregnancy Care ◽

Recent Developments

<p>Recently there has been a shift in health policy in New Zealand, as internationally, away from prenatal screening for fetal abnormalities targeting specific 'high risk' groups of pregnant women, towards the implementation of population-based screening programmes. As a result, for the majority of pregnant women in Western countries, prenatal screening is now undertaken as part of the standard 'package' of maternity care. This thesis explores the constitution of prenatal screening as a now taken-for-granted aspect of contemporary pregnancy care. It considers tensions between popular and medical understandings of the value and purpose of this practice, in particular examining the contradictory nature of discourses which, on one hand, construct acceptance of prenatal screening as an empowering 'choice' available to pregnant women, and on the other hand, as an institutionally-endorsed, morally appropriate practice of risk management. Recent developments within the New Zealand context are presented as a 'case study' of the representational politics of prenatal screening within contemporary public health policy. The question of informed consent for prenatal screening is a key focus within the research. It examines the extent to which the scope of women's choices and the degree of consent possible are materially shaped and constrained within the context of current clinical practice, and the broader climate of contemporary pregnancy care. Empirically, the research investigates key themes in women's experience of prenatal screening decisions within this climate, and explores the private 'moral work' undertaken by pregnant women as they navigate the contradictory imperatives which circulate in mainstream screening discourse. The findings of the research suggest a need for clinicians and policy makers to recognise prenatal screening as an ethically complex 'special case', qualitatively distinct from other projects of population-based health screening. It is argued that ethical practice in prenatal screening requires an approach which acknowledges the discursive and material factors which problematise liberal conceptions of prenatal screening as an authentic, deliberative 'choice' available to pregnant women.</p>

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