Down Syndrome Screening Research Articles

Health Technology Assessment and the Media: More Compatible than One May Think?

While the Health Technology Assessment (HTA) community has acknowledged the importance of public and consumer involvement in the HTA process, very few studies have examined how technology-related findings may be reported by the media to the broader public. This paper compares the content of press articles with the content of three Canadian HTA reports that respectively assess electroconvulsive therapy, first-trimester prenatal screening for Down syndrome, and prostate-specific antigen screening for prostate cancer. We qualitatively and quantitatively analyzed 186 press articles addressing the same technologies. Our results show that beyond stylistic emphasis, there is an important overlap between media coverage of these technologies and the content of HTA reports. Findings also highlight shared interests on which both researchers and journalists could build to enhance the communication of health information to the public.

Preliminary proteomic-based identification of a novel protein for Down's syndrome in maternal serum

Prenatal screening for Down's syndrome (DS) is in need of improvement. As a powerful platform, proteomics techniques could also be used for identification of new biomarkers for DS screening. In this case-control proteome study, pregnant women were diagnosed prenatally by karyotype analysis from amniotic fluid (AF). Maternal serum samples were collected from six pregnancies with fetuses affected by DS and six pregnancies with normal fetuses. First, we used two-dimensional electrophoresis and mass spectrometry to identify the different levels of expression of proteins in maternal serum between the DS and control groups in the second trimester. Second, we used bioinformatics to analyze the proteins by DAVID. Then, the interesting candidates were further tested by enzyme-linked immunosorbent assay (ELISA). Twenty-nine proteins were successfully identified in maternal serum obtained from pregnancies with fetuses affected by DS. The top five proteins up-regulated were serotransferrin (TF), alpha-1b-glycoprotein (A1BG), desmin (DES), alpha-1-antitrypsin (SERPINA1) and ceruloplasmin (CP), while serum amyloid P-component (APCS) was the most down-regulated protein. These 29 proteins were categorized based on binding, catalytic activity and enzyme regulator activity. The biological roles were involved in biological regulation, metabolic processes, cellular processes and response to a stimulus. Based on ELISA, the median concentrations of CP and complement factor B (CFB) were 332.3 and 412.3 ng/mL, respectively. The concentrations of CP and CFB were significantly higher in the DS group than in the control group (P < 0.05). In conclusion, proteomic approaches offer the possibility of further improving the performance of DS screening and our identification of up- and down-regulated proteins may lead to new candidates for DS screening.

Prenasal thickness in first‐trimester screening for Down syndrome

Prenasal thickness in first‐trimester screening for Down syndrome

The development of a peptide SRM-based tandem mass spectrometry assay for prenatal screening of Down syndrome

Two new biomarkers, serum amyloid-P (SAP) and plasma C1-inhibitor protein are elevated in the maternal circulation of mothers carrying Down syndrome foetuses. Much emphasis of late\ has been put on the lack of translational tests being developed following the identification of new biomarkers. We have created a single-reaction-monitoring (SRM) tandem mass spectrometry-based assay for the quantitation of these biomarkers and compared these results with an in-house developed immunofluorescence-based technique (IF). This MS-based assay is a rapid 5 min test and a simple "one pot reaction," requiring only 5μl of plasma. To evaluate the potential of SRM-based quantitation in a clinical setting, SAP and C1-inhibitor were quantitated in 38 normal and Down syndrome affected pregnancies. Plasma SAP levels in the Down's group were significantly raised at 10-14 weeks (p<0.0015) and 14-20 weeks (p<0.0001). Plasma C1-inhibitor levels were also observed significantly elevated in the Down's group (10-14 weeks, p<0.0193, 14-20 weeks, p<0.0001). Analysis using the IF technique did not show any significant elevation of plasma SAP levels or C1-inhibitor levels. This rapid and sensitive assay demonstrates the potential of multiplexed tandem MS-based quantitation of proteins in chemical pathology labs and in a more cost-effective, accurate manner than conventionally used antibody methods.

Influencing factors of utilization of prenatal screening for Down's syndrome

To describe the pregnant women's utilization of prenatal screening for Down's syndrome and its influencing factors. From October 2007 to December 2008, 4250 lying-in women in 54 hospitals were surveyed by stratified cluster sampling method in Zhejiang, Hunan and Sichuan, which located in Eastern, Central and Western China, respectively. Demographic characteristics, knowledge and health behaviors were collected by the questionnaire of lying-in women's utilization and influencing factors of prenatal screening for Down's syndrome. Whether to use prenatal screening was determined by the lying-in women's medical history. Chi-square test and logistic regression analysis were used to analyze data. Respondents' age was (26.92 ± 4.60) years old. The total utilization rate of prenatal screening for Down's syndrome was 40.0% (1696/4237), and screening utilization rates in Zhejiang, Hunan and Sichuan were 48.23% (682/1414), 41.73% (616/1476) and 29.55% (398/1347), respectively. Screening utilization rates of respondents with college degree or above and high school or below were 72.68% (697/959) and 30.46% (998/3276), respectively. Screening utilization rates of urban and rural respondents were 63.00% (952/1511) and 27.11% (732/2700), respectively. Screening utilization rates of respondents under 35 years old and over 35 years old were 41.40% (1645/3973) and 19.32% (51/264). All differences were significant (all P values < 0.05). A total of 79.14% (1419/1793) of respondents thought it was necessary to take prenatal screening for Down's syndrome, and 79.47% (1506/1895) of respondents received doctors' suggestions, 24.2% (654/2702) of respondents who heard of prenatal screening for Down's syndrome could figure out the main pathogenic factors, while 23.0% (621/2702) didn't know any factors; 77.8% (2102/2702) of respondents heard of prenatal screening for Down's syndrome, but 12.3% (259/2102) didn't know the appropriate gestational weeks to uptake the screening, 47.0% (988/2102) knew of prenatal screening for Down's syndrome through healthcare providers. Logistic regression analysis result demonstrated that living in Zhejiang (OR = 1.62, 95%CI: 1.26 - 2.08), city residence (OR = 2.06, 95%CI: 1.63 - 2.60), with positive attitude to screening (OR = 5.00, 95%CI: 3.97 - 6.29), pregnant women's age below 35 years old (OR = 3.86, 95%CI: 2.53 - 5.89), receiving advices from healthcare providers (OR = 12.64, 95.0%CI: 9.97 - 16.02), college degree or above educational level (OR = 2.67, 95%CI: 2.03 - 3.50) were facilitating factors on utilization of prenatal screening for Down's Syndrome. Pregnant women's use of prenatal screening for Down's syndrome was not enough, and living in zhejiang, higher education level, rural respondents with age under 35 years old, receiving advice from healthcare providers or not and their attitude toward necessity were significant promotive factors of utilization of prenatal screening for Down's syndrome.

Contingent screening for Down syndrome completed in the first trimester: a multicenter study

To assess a new contingent screening strategy for Down syndrome completed in the first trimester. First-trimester screening combining nuchal translucency thickness measurement and assessment of serum analytes (combined test) was offered to pregnant women who presented for prenatal care during the first trimester to nine health centers and community hospitals in the area served by the Catalan Public Health Service. If an intermediate risk (1/101-1/1000) for Down syndrome was identified, women were referred to the Hospital Clinic Barcelona for risk reassessment that included the use of secondary ultrasound markers (nasal bone, ductus venosus blood flow and tricuspid flow). Intermediate-risk women were divided into two subgroups for further analysis: high-intermediate risk (1/101-1/250) and low-intermediate risk (1/251-1/1000). We compared feasibility and efficacy of both combined and contingent screening strategies. The combined test, the first screening stage, was performed in 16 001 pregnant women, of whom 1617 (10.1%) were found to have an intermediate risk. Further division of this group showed that 1.8% (n = 289) of women were at high-intermediate risk and 8.3% (n = 1328) at low-intermediate risk. The contingent screening strategy significantly reduced the false-positive rate, from 3.0% to 1.3-1.8% (P < 0.001), without affecting the detection rate (which was 75-79% and 76%, with and without the contingent screening strategy, respectively). However, only 45% of intermediate-risk patients underwent the second screening step due to a preference among high-intermediate-risk (1/101-1/250) women for invasive testing and to low uptake among low-intermediate-risk (1/251-1/1000) women. The proposed first-trimester contingent strategy reduces the screen false-positive rate without impacting on the detection rate of Down syndrome. The low compliance observed in our study may prevent its use in certain populations.

First trimester Down syndrome screening is less effective and the number of invasive procedures is increased in women younger than 35 years of age

We evaluated the performance of first trimester screening for Down syndrome in women less than 35 years of age (study group) and in women aged 35 years or more (control group) in an unselected low-risk population. The study group comprised a total of 63,945 women who participated in the first trimester combined screening in public health care in Finland during the study period of 1 May 2002 to 31 December 2008. Women at the age of 35 or more (n = 13,004) were controls. Prevalence of Down syndrome, detection rate, false positive rate and number of invasive procedures needed to detect a single case of Down syndrome were analyzed in both groups. The overall prevalence of Down syndrome (n = 73) in the study group was 1:876. The number of detected cases was 54. The detection rate was 74.0% with a false positive rate of 2.8%. Number of invasive procedures needed to detect a single case of Down syndrome was 33. In the control group, the detection rate was 87.0% with a false positive rate of 11.9%. The number of invasive procedures needed to detect a single case of Down syndrome was 15. The differences in detection rate and false positive rate were significant, P < 0.012, P < 0.001, respectively. The overall detection rate given for the entire population is an overestimate for a woman younger than the age of 35, which should be taken into consideration when counselling women of that age.

Pregnancy-associated plasma protein A: spotlight on kidney diseases

Pregnancy-associated plasma protein A (PAPP-A) is a biomarker routinely used in screening for Down syndrome in the first trimester of pregnancy. It is also present in very small amounts in men and non-pregnant women. PAPP-A is a key regulator of local insulin-like growth factor (IGF) bioavailability - IGFs are essential for normal body size during fetal development, but they are associated with aging and age-related diseases. Measurement of circulating PAPP-A can provide valuable information not only in pregnant women (chromosomal anomalies and adverse pregnancy outcomes) but also in patients with coronary artery disease (contribution to diagnosis, prognostic value) and in patients with kidney diseases. PAPP-A is associated with renal function and proteinuria, is increased mainly in dialysis patients and decreases after kidney transplantation. It is an independent mortality predictor of hemodialysis patients and indicator of adverse outcome of transplanted patients. PAPP-A levels can be influenced by various chemicals and drugs, among them mainly heparin. Various assays for PAPP-A exist and the type of assay used in a study should be considered. This article reviews the data summarizing basic information about PAPP-A with a particular focus on the significance of PAPP-A in renal diseases.

Unconjugated estriol values between 14 and 22 weeks of gestation in relation to prenatal screening for Down syndrome

Unconjugated estriol values between 14 and 22 weeks of gestation in relation to prenatal screening for Down syndrome

Increased nuchal translucency in the presence of normal chromosomes

First trimester screening is presently offered to all pregnant women as a means of prenatal screening for Down syndrome, trisomy 18, and trisomy 13. Nuchal translucency measurement is a fundamental component of the screening protocol. A woman whose fetus' nuchal translucency is greater than the 95th percentile is also at increased risk for a multiplicity of other adverse pregnancy and pediatric outcomes, and as a consequence, counseling of patients about their testing options and range of pregnancy outcomes has become complex and difficult. The increased risk for chromosome abnormalities, congenital heart malformations, and pregnancy loss in the presence of an increased nuchal translucency is well documented. What has not been clearly defined is the incidence of other genetic syndromes, congenital defects, and adverse pregnancy and pediatric outcomes in the presence of increased nuchal translucency. Currently, Noonan syndrome is the only molecular genetic condition that has been shown to have a clear association with the finding of increased nuchal translucency in the first trimester. This article reviews the current literature on outcomes in pregnancies with an increased nuchal translucency and a normal karyotype. We summarize the range of outcomes detected in the first trimester with recommendations for further prenatal testing and counseling of patients.

Evaluation of population parameters and mathematical strategies for the calculation of prenatal risk of Down syndrome in the first trimester of pregnancy

To evaluate the population parameters applied to the calculation of risk for Down syndrome (DS) in the first trimester screening (FTS) and the comparison of performance obtained including or excluding maternal age from the mathematical algorithm. Three different calculation engines for prenatal risk of DS were developed on the basis of the population parameters from the Serum, Urine and Ultrasound Screening Study, the Fetal Medicine Foundation, and a combination of both of them. These calculators were evaluated in 14,645 first trimester pregnant women, including 59 DS affected fetuses, comparing their performance with that obtained by our commercial software Elipse® (Perkin Elmer Life and Analytical Sciences, Turku, Finland). Advanced first trimester screening (AFS) strategy was also analyzed, and a hybrid strategy (FTS + AFS) was evaluated. By selecting population parameters from the Serum, Urine and Ultrasound Screening Study, the detection rate increased from 76% (Elipse) to 86% with a small increase in the false positive rate (FPR), from 3.3% to 3.7%, respectively. DS screening performance significantly improved by using the hybrid strategy (AFS in pregnant women under 35 years and FTS in pregnant women over 35 years), with a 92% detection rate (FPR: 3.9%). In the present study, a new hybrid screening strategy has been proposed to achieve DS detection rates higher than 90%, for a convenient <4% FPR.

Median levels of serum biomarkers of fetal Down syndrome detected during the first trimester among pregnant Thai women

ObjectiveTo develop Thai-specific medians of serum pregnancy-associated plasma protein A (PAPP-A) and free β-human chorionic gonadotropin (hCG) levels during the first trimester of pregnancy and to compare these values to a Caucasian-specific model for the detection of fetal Down syndrome. MethodsSerum concentrations of PAPP-A and free β-hCG were measured during the first trimester in a group of 2339 Thai women undergoing normal singleton pregnancies. ResultsThai reference ranges of PAPP-A and free β-hCG were established by gestational age (70–98days). The equation of best fit for PAPP-A was: predicted median PAPP-A level=28.767 – 0.781×(gestational age in days)+0.006×(gestational age in days)2; r=0.986. The equation of best fit for free β-hCG was: predicted median free β-hCG level=465.332×10(–0.024×gestational age in days); r=0.881. Weight-corrected models were also derived for each biomarker. The Thai-specific reference ranges gave higher positive screening rates than the Caucasian-specific model, even after weight correction (5.1% versus 4.0%). The Thai-specific models were validated in an independent group of 302 pregnant women. ConclusionEthnic group-specific medians for PAPP-A and free β-hCG should be incorporated during first-trimester screening for fetal Down syndrome.

Prenatal testing for Down syndrome: The perspectives of parents of individuals with Down syndrome

This exploratory, descriptive study examined the views and opinions of parents of individuals with Down syndrome (DS) related to prenatal testing for DS and the use of age-based criteria to determine eligibility for this testing. This survey-based study was designed in collaboration with parents of individuals with DS and the British Columbia-based Lower Mainland Down Syndrome Society (LMDSS). The survey was a 26-item, self-report questionnaire, which was distributed by the LMDSS. Out of the 246 potentially eligible individuals that were mailed surveys, 101 participants returned their completed surveys. The availability of prenatal screening and diagnostic testing for DS was perceived positively by 55.1% and 64.7% of parents, respectively. More than half (60.2%) of participants felt that prenatal diagnostic testing for DS should be available to all pregnant women, regardless of age. In this study, views of Canadian parents of individuals with DS aligned with the prenatal testing policy recently adopted in the USA (whereby any woman, regardless of age or risk factors, can opt for prenatal diagnostic testing) rather than with new Canadian policy (whereby eligibility for diagnostic testing is no longer offered on the basis of age, but on the basis of other risk factors).

Quantitative fluorescent-polymerase chain reaction for rapid prenatal diagnosis of common aneuploidies

Objective To evaluate the clinical value of quantitative fluorescent polymerase chain reaction (QF-PCR) in rapid prenatal diagnosis of aneuploidies. Methods Twenty-two short tandem repeats (STR) and AMXY located on chromosome 13,18,21,X and Y were used as markers to examine 1740 samples from high risk pregnant women in Down syndrome screening and advanced maternal age(≥35 yrs) by QF-PCR.Samples were also tested by karyotype analysis and the results of the two methods were compared. Results Karyotype analysis and QF-PCR results were successfully obtained from 1690 samples. All QF-PCR reports were obtained within 48 hours after sample collection.For 1639 samples,normal results were obtained by both karyotype analysis and QF-PCR.Among 51 samples that were found abnormal by karyotype analysis,41 were abnormal in QF-PCR.The rapid tests found all numerical abnormalities involving chromosome 21,18,13,X and Y in prenatal diagnosis,including trisomy 21 (n =30),trisomy 18 (n =6),45,XO (n =1 ),47,XYY (n=1),47,XXX (n=1),69,XXX (n=1) and mosaic 47,XXY[94]/46,XX[6] (n=1)(47,XXY in QF-PCR).No false positive results were found.The results obtained by QF-PCR were consistent with those of cytogenetic studies in 99.4％ of the samples (1680/1690).Only ten cases of mosain and structural abnormality could not be found (0.6％,10/1690) by QF-PCR. Conclusions Rapid QF-PCR test might diagnose all aneuploidies involving chromosome 21,18,13,X and Y.It could provide rapid and accurate diagnosis for 99.4％ pregnant women with positive Down syndrome screening and advanced maternal age. Key words: Aneuploidy; Prenatal diagnosis; Polymerase chain reaction

Screening for Down syndrome

National policy recommends that all women should be offered screening for Down syndrome during pregnancy. Only in the last 10 years has there been any concerted effort to standardize this screening which was haphazard and geographically determined before this. A variety of screening methods have evolved, with a steady improvement in detection rate and concomitant reduction in the screen positive rate. Significant resources are required to translate exciting research into an effective and workable screening test, and the evolution of Down syndrome screening under the supervision of the UK National Screening Committee illustrates this well.

Decision Making Following a Prenatal Diagnosis of Down Syndrome: An Integrative Review

Prenatal screening for Down syndrome (DS) is a routine part of prenatal care in many countries, and there is growing interest in the choices women make following a prenatal diagnosis of DS. This review describes what is known about actual and hypothetical decision making following a prenatal diagnosis of DS and adds understanding about the factors that influence women's decision making. A search of empirical studies was conducted through electronic databases, major journals, and reference lists that were published in English between January 1999 and September 2010. Inclusion criteria were that the research explored attitudes toward continuation of pregnancy or induced abortion for DS and included at least 1 variable that explored factors influencing women's decision making following a prenatal diagnosis of DS. Studies that did not specify DS, unpublished manuscripts, review articles, and book chapters were excluded. A total of 11 studies were identified that met the inclusion criteria. The decision to undergo an induced abortion varied depending on whether participants were prospective parents recruited from the general population (23%-33% would terminate), pregnant women at increased risk for having a child with DS (46%-86% would terminate), or women who received a positive diagnosis of DS during the prenatal period (89%-97% terminated). Multiple factors influence women's decision making following a diagnosis of DS, including demographic factors such as religion, maternal age, gestational age, number of existing children, and history of induced abortion. Psychosocial factors including perceived parenting burden/reward, quality of life for a child with DS, attitudes toward and comfort with individuals with disabilities, and support from others also are important influences. Multiple factors influence the decisions pregnant women make following the diagnosis of fetal DS. Therefore, it is critical that health care providers who work with pregnant women are aware of these factors.

Informing on prenatal screening for Down syndrome prior to conception. An empirical and ethical perspective

In most Western countries, information on prenatal screening for Down syndrome is provided in the first-trimester of pregnancy. The purpose of this study was to examine whether this information should additionally be provided before pregnancy to improve the informed decision-making process. In an empirical study, we obtained data from pregnant women with respect to their preferences regarding information on prenatal screening preconceptionally. Questionnaire data (n = 510) showed that 55.7% of responding women considered participating in prenatal screening for Down syndrome before pregnancy. 28.0% of women possessed information on prenatal screening preconceptionally. 84.6% preferred not to receive information preconceptionally in retrospect. In an ethical analysis, we elaborated on these preferences by weighing pros and cons. We considered two arguments against the provision of information on prenatal screening preconceptionally: women's preference to receive information in a step-by-step manner, and the risk of providing a directive message. We identified three reasons supporting its provision preconceptionally: the likelihood of making an informed decision could, firstly, be increased by "unchaining" the initial information from possible subsequent decisions, and, secondly, by providing women sufficient time to deliberate. Thirdly, the probability of equal access to prenatal screening may increase. To conclude with, we propose to incorporate an information offer on prenatal screening for Down syndrome in preconception care consultations. By offering information, instead of providing information, prospective parents are enabled to either accept or decline the information, which respects both their right to know and their right not-to-know.

DNA Sequencing of Maternal Plasma to Detect Down Syndrome

The use of current screening for Down syndrome is relatively effective and can detect up to 90% of cases with a false-positive rate of about 5%. However, follow-up invasive procedures are associated fetal loss in as many as 1 in 200 tests. Alternative noninvasive diagnostic tests have been investigated that can detect fetal cell-free DNA in maternal blood. In 2008, 2 reports described the use of such a test, massively parallel shotgun sequencing (MPSS), which is an internally validated test based on next-generation sequencing. Subsequent studies with the MPSS test were promising and suggested a detection rate of at least 98% at a false-positive rate of 2% or lower. However, sample sizes were small (13–86 Down syndrome cases), and the test was not performed in Clinical Laboratory Improvement Amendments (CLIA)-certified laboratories. This blinded, nested case-control study analyzed the use of MPSS within a cohort of 4664 pregnancies. Women at high risk for Down syndrome were enrolled at 27 prenatal diagnostic centers worldwide. The test was evaluated in 212 Down syndrome and 1484 matched euploid pregnancies. Similar numbers of Down syndrome cases were diagnosed in the first and second trimester. None of the samples had been previously tested. A CLIA-certified commercial laboratory performed the primary testing. A subset of samples was sent to a CLIA-certified university laboratory for confirmatory testing. MPSS testing correctly identified 209 of 212 Down syndrome fetuses; the detection rate was 98.6%, with a 95% confidence interval of 95.9–99.7. The false-positive rate was 0.2% (3/1471), with a 95% confidence interval of <0.1–0.6. Testing failed in 13 euploid pregnancies (0.8%). After testing was concluded but before unblinding, the primary testing laboratory adjusted the chromosome 21 data for guanine cytosine base content to assess alternative methods of interpreting the MPSS results. Adjusting chromosome 21 counts for guanine cytosine base content had the largest impact on improving test performance (reduced false-negative and false-positive results). These findings show that measuring maternal plasma DNA in a large cohort of high-risk pregnancies can identify nearly all cases of Down syndrome at a very low false-positive rate. Although confirmation by invasive testing is needed, data from this and previous studies suggest the benefit of this test in women at high risk of Down syndrome.

Screening results analysis on Down syndrome in 13736 case of middle period pregnancy

Objective To determine serum contents of maternal serum markers including alpha fetoprotein(AFP),chorionic gonadotrophin(HCG)and unconjugated estriol(uE3)in mid-pregnancy women,and explore its clinical value in screening for Down syndrome(DS).Methods ELISA was used to test the concentrations of AFP,HCG and uE3 in maternal serum.The morbidities of DS were calculated base on the results with supported software combining with factors of the maternal age,gestation age and weight.Hereditary consultation was provided for the high-risk pregnant women,amniocentesis was done under their agreements.Each case was followed till one month after the fetus birth.Results 1017 pregnancies among 13736 women of 15 to 20 plus 6 weeks pregnancy were screen positive,728 pregnancies were detected at high risk for DS,138 pregnancies were detected as high risk for open neural tube defects (ONTD),151 pregnancies were detected as high risk for trisomy 18.In the screening positive pregnancies,we found 5 cases of DS,4 cases of trisomy 18,4 cases of hydrocephalus,1 case of dilatation of ventricle,2 cases of DS were found in the screening negative pregnancies.Conclusion The results in this paper indicate that triple screen test for middle period serum of pregnancy women is important for decreasing the birth rate of DS and neural tube defects. Key words: Alpha fetoprotein; Chorionic gonadotrophin; Unconjugated estriol; Down' s syndrome; Prenatal screening

A qualitative investigation of the decision‐making process of couples considering prenatal screening for Down syndrome

The aim of this study was to investigate how couples regard screening information and how they make subsequent decisions about undergoing prenatal screening for Down syndrome. Twenty semi-structured interviews were conducted to explore aspects of the decision-making process. Interviews were digitally recorded and transcribed verbatim, and data were analysed using the framework approach. Couples reported a strong desire for a joint but ultimately private decision-making process and saw the main role of their midwife as an information provider. Considerable confusion existed over which screening tests were available via the National Health Service and which were offered privately. Provision of experiential information regarding both subsequent diagnostic tests and the experience of living with Down syndrome would have been beneficial. This study shows that couples would benefit from receiving experiential information when they are deciding about Down syndrome screening. Future research should be conducted to establish what form such information should take, the most helpful means to provide such information, and whether such information would also be useful in other contexts where people need to make decisions whether to undergo screening.