Evaluation of the clinical performance of noninvasive prenatal testing at a Japanese laboratory

Systematic Review of Accuracy Differences in NIPT Methods for Common Aneuploidy Screening

Background/Objectives: Non-invasive prenatal testing (NIPT) has become a widely used method for screening common fetal aneuploidies due to its high sensitivity and specificity compared to traditional screening methods. With various NIPT technologies available, such as whole-genome sequencing (WGS), single nucleotide polymorphisms (SNPs), microarray, and rolling circle amplification (RCA), understanding the accuracy and reliability of each method is critical for clinical decision-making. However, comprehensive evaluations comparing the performance of these NIPT methods, especially in terms of predictive values for trisomy detection, remain limited. A systematic review of the difference in accuracy of the different NIPT methods used for common aneuploidy screening. Methods: A systematic review of former clinical studies using different NIPT methods, such as whole-genome sequencing (WGS), a targeted method of single nucleotide polymorphisms (SNPs), microarray and rolling circle amplification (RCA). We collected data from the PubMed, Embase, Web of Science, Scopus, clinicaltrials.gov, and Cochrane library from the last 20 years, between 2003 January and 2023 October, without any language, search filter or publication type restrictions. Results: Two authors selected twenty articles including twenty-one studies to perform the systematic review. In these studies, altogether 92,164 pregnant women were tested by genomics-based non-invasive prenatal testing (NIPT). We extracted data on true positive, false positive, false negative, and true negative values from each study, and calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) from them. We collected data regarding trisomy 21 (T21), trisomy 18 (T18) and trisomy 13 (T13) detection from all studies. Conclusions: As a conclusion, for the detection of common fetal trisomies, different methods of NIPT perform similarly in terms of clinical sensitivity, specificity and NPV. However, the tests utilizing SNP and RCA had lower PPV values than other NIPT methods. Our research indicates all NIPT methods showed greater sensitivity for the detection of T21, above 97%, than traditional screening tests. For T18 detection, the targeted method with the microarray had a lower sensitivity compared to other tests. The SNP and the microarray-based test had high PPV, whilst the other tests, utilizing WGS, and the test with RCA had quite low PPV. Regarding T13 detection, all of the tests performed similarly in terms of clinical sensitivity, specificity, PPV, and NPV (with one exception-one of the tests using WGS had lower PPV). According to these results, there was no significant difference between the methods of NIPT, such as WGS, SNPs, microarray, and RCA, used to detect common trisomies, but the variation in PPV underlines the importance of invasive tests to derive positive NIPT results. We suggest that NIPT combined with US screening for structural abnormalities could further improve the utility of the non-invasive tests in pregnancy. This is the first independent systematic review into the efficacy of the different NIPT methods.

Comparing the Introduction and Implementation of Noninvasive Prenatal Testing (NIPT) in Japan, the Netherlands, and the United States: An Integrative Review

Previous studies suggest that NIPT's implementation differed widely across countries but offer limited insight into what shaped these differences. To address this gap, we conducted an in-depth analysis of how NIPT was incorporated into prenatal care in the US, the Netherlands, and Japan-countries with similar economic status-to identify actionable lessons. We conducted an integrative literature review on the process of introducing and implementing NIPT, stakeholders' roles, documented considerations in the decision to introduce NIPT, implementation choices, and NIPT uptake. We included 184 sources, including white and gray literature and non-English sources. We identified 17 considerations that were documented to have influenced the decision whether to introduce NIPT across five domains: clinical considerations, ethical considerations and societal values, financial considerations, demand and capacity and applicable oversight. Fewer factors seem to have been considered in the US as compared to Japan or the Netherlands. Countries subsequently made choices on how to implement NIPT-we identified 35 such choices. While most of the identified choices were eventually considered by all three countries, they made different decisions (e.g., on out-of-pocket costs). In 2022, the estimated proportion of pregnant persons who used NIPT was 58% in the Netherlands, 49% in the US, and 9% in Japan. While differences in cultural values, population characteristics, and healthcare systems explain some variation, we identified other more adaptable aspects of the decision-making process (e.g., oversight) that may be useful for countries introducing NIPT or similar technologies to consider.

The expressivist argument for recent policy changes regarding the provision of prenatal testing in Japan

The Japanese government and medical professionals have negative attitudes toward the provision of prenatal testing and related information due to social concern regarding discrimination against persons with disabilities. However, with the rapid increase in the number of non-invasive prenatal tests, particularly at non-certificated medical facilities, in response to the growing demand from pregnant women, the Japanese government and medical professional associations have enacted radical changes marking an active commitment to the provision of information on these services. While a major justification for these policy changes is to ensure respect for reproductive autonomy and women's self-determination, they may reinforce the concern regarding discrimination. This article investigated the argument that these new policies may reinforce discrimination and examined three objections to this argument. The results revealed that the recent policy changes, particularly for specific fetal traits, may imply a negative belief about people living with the same traits. Consequently, fundamental institutional changes are necessary.

Impact of the new government-involved noninvasive prenatal testing certification system on the awareness of pregnant women about noninvasive prenatal testing in Japan

AIM

In Japan, noninvasive prenatal testing (NIPT) has been performed by facilities accredited by the Japanese Society of Obstetrics and Gynecology since 2013. However, since 2016, with the implementation of NIPT, which can only be performed by blood sampling, non-obstetricians have been involved in prenatal testing. Therefore, in July 2022, a new government-involved NIPT certification system based on Health Sciences Council guidelines was introduced to ensure access to prenatal testing information for pregnant women.

METHODS

This survey was conducted in February 2023 and was the first survey after the certification system implementation. We conducted a web-based survey of 1227 pregnant women and nursing mothers who underwent NIPT after July 2022 to evaluate their experiences.

RESULTS

Respondents were categorized by certification status as certified (C: 56%), non-certified (non-C: 23%), or uncertain (Q: 20%). The C group with a higher mean age at examination (35.0 ± 4.5 years) paid lower examination fees, received longer pre- and post-examination explanations, and underwent more weekday examinations (80%) than the other groups. Most respondents, 67%, 48%, and 53% in the C, non-C, and Q groups, respectively (p < 0.0001), stated that "NIPT needs to be regulated by the government or academic societies." The non-C group was more likely to say, "Insufficient post-test explanations at the laboratory made me more anxious," than the other groups when the testing results were non-negative (p = 0.015).

CONCLUSIONS

Despite government regulation, some pregnant women choose convenience over certified facilities, risking inadequate care. The government should ensure that NIPT is a safe option for all pregnant women.

Performance analysis of non-invasive prenatal testing for trisomy 13, 18, and 21: A large-scale retrospective study (2018-2021)

Background

Non-invasive prenatal tests (NIPT) are used to screen for trisomy 21, 18, and 13. This study investigated NIPT performance and the clinical significance of its results.

Methods

Pregnant women (n = 282,911) participating in a free NIPT (April 2018-December 2021) were screened for common trisomies, and the results were retrospectively analyzed. NIPT performance was evaluated by its positive predictive value (PPV), sensitivity, and specificity. Results were analyzed using number, percentage, and chi-squared/t-test analyses.

Results

After NIPT screening, patients with common trisomies (n = 746) included 457 with T21, 160 with T18, and 129 with T13. Seven false negative cases were identified. High PPV (86.81 %, 56.81 %, 18.18 %), sensitivity (99.25 %, 98.33 %, 100.00 %), and specificity (99.98 %, 99.98 %, 99.97 %) values were detected for trisomy 21, 18, and 13, respectively. The PPVs of common trisomies were significantly different between pregnant women older than 35 (85.53 %, 136/159) and those aged 35 or younger (58.90 %, 311/528) (χ2 = 125.02, P = 2.20e-16). As the NIPT uptake increased from 2018 to 2021, live-born birth defect incidence decreased.

Conclusion

NIPT performed well in screening for T21, T18, and T13. Our discoveries offer an important and useful guideline in laboratory and clinical genetic counseling.

Sayed A, Imoto A, Sato M, Dila KAS, Huy NT, Moji K. Non-Invasive Prenatal Testing (NIPT) Implementation in Japan: A Comparison with the United Kingdom, Germany, Italy, Sweden, and Taiwan

INTRODUCTION

The Non-Invasive Prenatal Testing (NIPT) guideline was issued and applied in 2013 by the Japanese Medical Association. Since being issued, the NIPT practice in Japan still has some problems related to indication, access, cost coverage and uniformity. Therefore, our study aimed to identify the Japanese challenges of adopting NIPT into prenatal diagnosis by comparing the system and process with other countries.

METHOD

The United Kingdom, Germany, Italy, Sweden, and Taiwan were purposefully selected for comparison. All the countries, including Japan, introduced NIPT. The literature and information searches were conducted using PubMed, SCOPUS, Google Scholar, CiNii and Google searching engine.

RESULTS

The process of NIPT in Japan was very different from the other countries. Japan is the only country that indicated NIPT for only pregnant women over 35 years old in certificated facilities and did not have a policy regarding providing information on prenatal screening and NIPT to all women. Japan also did not have a policy regarding abortion due to fetal abnormalities. The practice of NIPT guidelines is different between non-certified and certified facilities. NIPT fee was the highest in Japan and was not covered by insurance.

CONCLUSION

Pregnant women in Japan suffered from disparities in information access, economic burden, geographic location, and practice of NIPT guidelines between the certified and the non-certified facilities. Pregnant women-centered prenatal diagnosis policy, including NIPT, should be established in Japan by learning cases from other countries.

A Critical Evaluation of Validation and Clinical Experience Studies in Non-Invasive Prenatal Testing for Trisomies 21, 18, and 13 and Monosomy X

Non-invasive prenatal testing (NIPT) for trisomies 21, 18, 13 and monosomy X is widely utilized with massively parallel shotgun sequencing (MPSS), digital analysis of selected regions (DANSR), and single nucleotide polymorphism (SNP) analyses being the most widely reported methods. We searched the literature to find all NIPT clinical validation and clinical experience studies between January 2011 and January 2022. Meta-analyses were performed using bivariate random-effects and univariate regression models for estimating summary performance measures across studies. Bivariate meta-regression was performed to explore the influence of testing method and study design. Subgroup and sensitivity analyses evaluated factors that may have led to heterogeneity. Based on 55 validation studies, the detection rate (DR) was significantly higher for retrospective studies, while the false positive rate (FPR) was significantly lower for prospective studies. Comparing the performance of NIPT methods for trisomies 21, 18, and 13 combined, the SNP method had a higher DR and lower FPR than other methods, significantly so for MPSS, though not for DANSR. The performance of the different methods in the 84 clinical experience studies was consistent with validation studies. Clinical positive predictive values of all NIPT methods improved over the last decade. We conclude that all NIPT methods are highly effective for fetal aneuploidy screening, with performance differences across methodologies.