IQMH Proficiency Testing is proud to share this article prepared and authored by Tamara Ashfield, Elizabeth McCready, Mary Shago, Hong Wang, Elizabeth Sinclair‐Bourque, Eva Cappa, Amanda Piche Marolt, Kathy Chun

Practice patterns of prenatal and perinatal testing in Canadian cytogenetics laboratories

ABSTRACT

Objective

To survey patterns of practice in Canadian cytogenetics laboratories and evaluate whether newer technologies have influenced testing algorithms for the detection of common aneuploidies and other genomic imbalances in the prenatal and perinatal settings.

Methods

Cytogenetics laboratories across Canada were invited to participate in two patterns‐of‐practice surveys: one in 2016 and one in 2019. They were asked to identify the prenatal and perinatal specimen types tested at their facility and which testing methods were used for initial testing and for follow‐up.

Results

All clinical laboratories performing prenatal testing offer rapid aneuploidy detection (RAD). Most laboratories also offer microarray analysis. A positive result is either followed up by karyotyping or no further testing is performed. For prenatal samples, a negative result may be followed up by microarray or karyotyping and is dependent on the reason for referral. For perinatal samples, availability of microarray to follow up a negative result is increasing.

Conclusions

Since 2016, the availability of RAD as a first‐line test in Canadian cytogenetics laboratories remains consistent, while microarray has become the preferred follow‐up testing method over traditional karyotyping following a normal RAD result. Despite a universal healthcare system, disparities in prenatal and perinatal cytogenetic testing algorithms are apparent.

Published in the journal of Prenatal Diagnosis, early online publication, April 25, 2021. Read the article.