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Objective: To ensure accurate and appropriate reporting of non-invasive prenatal testing (NIPT) results, the standard of testing should be measured and monitored by participation in external quality assessment (EQA) schemes. The findings from international pilot EQAs for NIPT for the common trisomies are presented., Methods: In the first pilot, three EQA providers used artificially manufactured reference materials to deliver an EQA for NIPT. The second pilot used clinically collected maternal plasma samples. The testing and reporting for aneuploidy status was performed by participating laboratories using routine procedures. Reports were assessed against peer ratified criteria and EQA scores were returned to participants., Results: Forty laboratories participated in the first. Genotyping accuracy was high; four laboratories reported a critical genotyping error (10%) and two reported partial results. Eighty seven laboratories participated in the second pilot using maternal plasma, two reporting a critical genotyping error (2.3%). For both rounds, report content was variable with key information frequently omitted or difficult to identify within the report., Conclusions: We have successfully delivered an international pilot EQA for NIPT. When compared with currently available manufactured materials, EQA for NIPT was best performed using clinically collected maternal plasma. Work is required to define and improve the standard of reporting., (© 2019 The Authors Prenatal Diagnosis Published by John Wiley & Sons Ltd.)

Objective: Non-invasive prenatal testing (NIPT) for trisomies 13, 18 and 21 is used worldwide. Laboratory reports should provide clear, concise results with test limitations indicated, yet no national or local guidelines are currently available. Here, we aim to present minimum best practice guidelines., Methods: All laboratories registered in the three European quality assurance schemes for molecular and cytogenetics were invited to complete an online survey focused on services provided for NIPT and non-invasive prenatal diagnosis. Laboratories delivering NIPT for aneuploidy were asked to submit two example reports; one high and one low risk result. Reports were reviewed for content and discussed at a meeting of laboratory providers and clinicians held at the ISPD 2016 conference in Berlin., Results: Of the 122 laboratories that responded, 50 issued reports for NIPT and 43 of these submitted sample reports. Responses and reports were discussed by 72 attendees at the meeting. Consensus opinion was determined in several areas and used to develop best practice guidelines for reporting of NIPT results., Conclusions: Across Europe, there is considerable variation in reporting NIPT results. Here, we describe minimum best practice guidelines, which will be distributed to European laboratories, and reports audited in subsequent external quality assurance cycles. © 2017 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd., (© 2017 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.)

We present 16 cases, 10 de novo and 6 familial, in which extra structurally abnormal chromosomes (ESACs) were diagnosed prenatally and identified by fluorescence in situ hybridization (FISH) studies with follow up from birth. We review the literature on prenatally diagnosed ESACs arising de novo and suggest a management protocol for these cases.

Karyotyping of a fetus with mild cerebral ventriculomegaly detected with ultrasound at 23 weeks revealed two apparently balanced structural rearrangements in mosaic form. Using conventional cytogenetics and FISH, the chromosomal constitution was identified as 46,XX,t(3;10)(p13;q21.1),inv(6)(p23q12)/46,XX. A 46,XX chromosome constitution was predominantly present in the skin whereas in the fetal blood the cell line with two balanced chromosome rearrangements was selectively retained. To the best of our knowledge this is the first prenatal case of mosaicism for two de novo balanced structural chromosome rearrangements to be reported.