{"id":116174,"date":"2025-09-25T10:04:56","date_gmt":"2025-09-25T01:04:56","guid":{"rendered":"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/"},"modified":"2025-09-25T10:13:54","modified_gmt":"2025-09-25T01:13:54","slug":"nipt-down-syndrome-score","status":"publish","type":"post","link":"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en","title":{"rendered":"Understanding Positive Scores and Retesting Criteria for Down Syndrome"},"content":{"rendered":"\n<p>In recent years, non-invasive prenatal testing (<a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a>) has become increasingly common in prenatal care. This testing allows for the assessment of fetal chromosomal abnormalities early in pregnancy. Among these, <strong>Down syndrome (Trisomy 21)<\/strong> receives the most attention. This article provides a detailed explanation of what a positive <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> score means, how to determine the need for retesting, the accuracy of the test, and its clinical applications, based on the latest research and guidelines.<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_84 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">\u76ee\u6b21<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#1_What_is_NIPT\" >1. What is NIPT?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#2_What_is_a_Positive_Score_for_Down_Syndrome\" >2. What is a Positive Score for Down Syndrome?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#3_Criteria_for_Retesting\" >3. Criteria for Retesting<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#3%E2%80%911_Retesting_for_High-Risk_Scores\" >3\u20111. Retesting for High-Risk Scores<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#3%E2%80%912_Managing_Borderline_Scores\" >3\u20112. Managing Borderline Scores<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#4_Factors_Affecting_Positive_Scores\" >4. Factors Affecting Positive Scores<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#5_Clinical_Use_and_Considerations\" >5. Clinical Use and Considerations<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#6_Summary_So_Far\" >6. Summary So Far<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#7_Important_Notes_for_Pregnant_Women_and_Families\" >7. Important Notes for Pregnant Women and Families<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#8_Future_Outlook\" >8. Future Outlook<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#9_Conclusion\" >9. Conclusion<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\/#References\" >References<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1_What_is_NIPT\"><\/span>1. What is NIPT?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> is a non-invasive screening method that analyzes cell-free fetal DNA (cfDNA) present in maternal blood to assess the risk of chromosomal abnormalities in the fetus. Unlike traditional invasive procedures such as chorionic villus sampling (CVS) or amniocentesis, <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> only requires a blood sample, significantly reducing the risk of miscarriage.<\/p>\n\n\n\n<p><strong>Chromosomal abnormalities assessed by <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> include:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Trisomy 21 (Down syndrome)<\/li>\n\n\n\n<li>Trisomy 18 (Edwards syndrome)<\/li>\n\n\n\n<li>Trisomy 13 (Patau syndrome)<\/li>\n\n\n\n<li>Sex chromosome abnormalities (e.g., Turner syndrome)<\/li>\n<\/ul>\n\n\n\n<p>Down syndrome is particularly prioritized in <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> due to its higher birth prevalence and the strong interest among pregnant women and their families.<\/p>\n\n\n\n<p><em>(Reference: Gil MM, Quezada MS, Bregant B, et al. Analysis of cfDNA in maternal blood in screening for fetal aneuploidies: updated meta-analysis. Ultrasound Obstet Gynecol. 2015)<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2_What_is_a_Positive_Score_for_Down_Syndrome\"><\/span>2. What is a Positive Score for Down Syndrome?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> results are typically reported as a \u201crisk ratio\u201d or \u201cpositive probability (positive score).\u201d This is a statistically calculated probability of the fetus having Down syndrome, based on the proportion of cfDNA derived from chromosome 21 in the sample.<\/p>\n\n\n\n<p><strong>Interpreting Positive Scores:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Low Risk (Negative):<\/strong> The score is below the threshold; the likelihood of Trisomy 21 is extremely low.<\/li>\n\n\n\n<li><strong>High Risk (Positive):<\/strong> The score exceeds the threshold; the likelihood of Trisomy 21 is higher.<\/li>\n\n\n\n<li><strong>Uncertain (Borderline \/ Gray Zone):<\/strong> The score does not clearly reach the threshold; retesting or additional testing is recommended.<\/li>\n<\/ul>\n\n\n\n<p>Although specific thresholds vary by testing provider, a risk lower than 1:100 is generally considered low, and 1:100 or higher is considered high.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3_Criteria_for_Retesting\"><\/span>3. Criteria for Retesting<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>A positive <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> score does not guarantee that the fetus has Down syndrome. <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> is a screening test\u2014not a diagnostic one. Thus, further assessment is essential in positive cases.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E2%80%911_Retesting_for_High-Risk_Scores\"><\/span>3\u20111. Retesting for High-Risk Scores<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Repeat <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> through blood draw<\/strong><br>False positives may occur due to low cfDNA concentrations or sample quality, so a second <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> may be performed on the same individual.<\/li>\n\n\n\n<li><strong>Invasive diagnostic testing (CVS or amniocentesis)<\/strong><br>For high-risk scores, confirmatory diagnosis is recommended, acknowledging the associated miscarriage risk.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E2%80%912_Managing_Borderline_Scores\"><\/span>3\u20112. Managing Borderline Scores<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>When scores are near the cutoff, repeat testing is used to verify score consistency.<\/li>\n\n\n\n<li>Women with low cfDNA fractions (e.g., those with high BMI) may be at increased risk for false negatives, necessitating personalized evaluation by a physician.<\/li>\n<\/ul>\n\n\n\n<p><em>(Reference: Benn P, Borrell A, Cuckle H, et al. Review of <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> performance for Down syndrome using maternal blood cfDNA. Prenat Diagn. 2013)<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4_Factors_Affecting_Positive_Scores\"><\/span>4. Factors Affecting Positive Scores<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Understanding what affects the score helps improve decision-making about retesting.<\/p>\n\n\n\n<p><strong>Maternal Factors:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>High BMI: Dilution of cfDNA may lower scores<\/li>\n\n\n\n<li>Pregnancy complications (e.g., preeclampsia): Can contribute to false positives<\/li>\n<\/ul>\n\n\n\n<p><strong>Fetal Factors:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Mosaicism (partial chromosomal abnormalities)<\/li>\n\n\n\n<li>Twin pregnancy: Interpreting scores is complex if only one fetus is affected<\/li>\n<\/ul>\n\n\n\n<p><strong>Technical Factors:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>cfDNA extraction quality and library preparation accuracy<\/li>\n\n\n\n<li>NGS (next-generation sequencing) analysis algorithms<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"5_Clinical_Use_and_Considerations\"><\/span>5. Clinical Use and Considerations<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> reduces the psychological burden and invasive testing risks for pregnant women. However, the following points must be observed:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A positive score is <strong>not<\/strong> a diagnosis \u2192 confirm with invasive testing<\/li>\n\n\n\n<li>A negative score does <strong>not<\/strong> mean zero risk \u2192 rare false negatives exist<\/li>\n\n\n\n<li><strong>Genetic counseling is crucial<\/strong> \u2192 results must be explained clearly by a physician or counselor<\/li>\n\n\n\n<li>Example retesting flow:<br>\u2002<a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> performed \u2192 Positive score \u2192 High risk \u2192 Consider invasive test<br>\u2002Borderline \u2192 Repeat <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> or additional test<br>\u2002Low risk \u2192 Continue with routine pregnancy care<\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img decoding=\"async\" width=\"640\" height=\"427\" src=\"\/nipt\/wp-content\/uploads\/2025\/09\/32362514_s-2.webp\" alt=\"\u533b\u8005\" class=\"wp-image-116165\"\/><\/figure><\/div>\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"6_Summary_So_Far\"><\/span>6. Summary So Far<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> is an innovative test that reduces maternal burden and enables early risk identification for Down syndrome<\/li>\n\n\n\n<li>A positive score is a <strong>screening result<\/strong>, not a definitive diagnosis<\/li>\n\n\n\n<li>Accurate understanding of retesting criteria and close collaboration with healthcare providers ensures safe and effective pregnancy management<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"7_Important_Notes_for_Pregnant_Women_and_Families\"><\/span>7. Important Notes for Pregnant Women and Families<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>When undergoing <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a>, do not rely solely on the positive or negative score. Consider the following:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Timing of testing<\/strong><br>\u2002After 10 weeks of gestation, fetal cfDNA becomes sufficient for accurate analysis<\/li>\n\n\n\n<li><strong>Differences among testing companies<\/strong><br>\u2002Each has different algorithms and score thresholds \u2192 Always confirm with your provider<\/li>\n\n\n\n<li><strong>Twin pregnancy or previous pregnancy history<\/strong><br>\u2002Twin pregnancies may show intermediate scores if only one fetus is affected.<br>\u2002A history of chromosomal abnormality warrants more intensive genetic counseling<\/li>\n\n\n\n<li><strong>Psychological support<\/strong><br>\u2002A positive score can cause stress \u2192 Counseling provides both accurate information and emotional support<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"8_Future_Outlook\"><\/span>8. Future Outlook<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> technology is evolving rapidly. Future developments may allow earlier and broader detection of chromosomal and genetic disorders. Machine learning and AI-based analysis are also expected to further reduce false positives and negatives.<\/p>\n\n\n\n<p>This advancement will enable families to better understand fetal health and contribute to more accurate prenatal diagnostics and reduced emotional stress.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"9_Conclusion\"><\/span>9. Conclusion<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> is a <strong>screening<\/strong> test; a positive score is a probability indicator<\/li>\n\n\n\n<li>Determining the need for retesting or diagnosis requires consultation with a doctor or genetic counselor<\/li>\n\n\n\n<li>Factors affecting the positive score include maternal, fetal, and technical elements<\/li>\n\n\n\n<li>Psychological support for the pregnant woman and family is an essential part of care<\/li>\n\n\n\n<li>Future improvements in analysis accuracy and target conditions are anticipated<\/li>\n<\/ul>\n\n\n\n<p>Proper understanding of this information allows families to make informed decisions and safely use <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/\">NIPT<\/a> in assessing risks like Down syndrome.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"References\"><\/span><strong>References<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Benn P, et al. Prenatal detection of aneuploidy using maternal plasma DNA sequencing. Prenat Diagn. 2013<\/p>\n\n\n\n<p>ACOG Committee Opinion No. 682. Screening for fetal chromosomal abnormalities. Obstet Gynecol. 2016<\/p>\n","protected":false},"excerpt":{"rendered":"In recent years, non&#8230;\n <a href=\"https:\/\/www.hiro-clinic.or.jp\/nipt\/nipt-down-syndrome-score\/?lang=en\">\u7d9a\u304d\u3092\u8aad\u3080<\/a>","protected":false},"author":122,"featured_media":116162,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[97],"tags":[],"class_list":["post-116174","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/posts\/116174","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/users\/122"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/comments?post=116174"}],"version-history":[{"count":2,"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/posts\/116174\/revisions"}],"predecessor-version":[{"id":116181,"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/posts\/116174\/revisions\/116181"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/media\/116162"}],"wp:attachment":[{"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/media?parent=116174"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/categories?post=116174"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hiro-clinic.or.jp\/nipt\/wp-json\/wp\/v2\/tags?post=116174"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}