A new rapid test can detect missing or extra chromosomes as part of prenatal and fertility care.

The Short-read Transpore Rapid Karyotyping (STORK) test developed by researchers at Columbia University, New York, can detect abnormalities in the number of chromosomes, known as aneuploidy. Aneuploidy can take the form of either missing or extra chromosomes and can lead to congenital and genetic disorders and are a leading cause of miscarriage.

'STORK testing takes hours instead of days to weeks, costs a couple of hundred dollars instead of a couple of thousand dollars, and can be done at the point of care instead of shipping to a reference lab,' lead author Dr Zev Williams told HuffPost.

Publishing their results in the New England Journal of Medicine, the authors claim the test can be used on genetic material from a number of sources: cells biopsied from IVF embryos before freezing or transfer to the uterus, samples from a developing fetus taken via chorionic villus sampling (CVS) or amniocentesis, or tissue from miscarriages.

DNA was extracted from the samples, and in the case of IVF embryos an additional DNA amplification step was required. The chromosomes of each sample were then examined to determine the karyotype, which involves sorting chromosomes by features such as length to help identify abnormalities.

The STORK equipment can run up to ten tests simultaneously, which could potentially bring costs as low as $50 per sample.

They demonstrated the test's accuracy through 218 comparative tests on different tissue samples during the study. The results were compared with standard testing methods and demonstrated comparable accuracy of between 98-100 percent.

Further verification was provided by an independent laboratory certified for quality testing. They tested STORK on a further 60 samples and showed a 100 percent match with standard prenatal test results.

In cases of CVS or amniocentesis, swifter results can reduce anxious waiting time for pregnant people and their partners, while the option to understand the cause of pregnancy loss could be welcome for some patients:

'If the pregnancy loss was found to be genetically abnormal, that provides a sense of closure, ameliorates feelings of self-blame and guilt, and provides reassurance for [a patient's] next pregnancy,' said Dr Williams who is an obstetrician gynaecologist specialising in infertility and recurrent miscarriage at Columbia's Irving Medical Centre.

The researchers also suggest that the test could save IVF patients time and money, avoiding the need to freeze all embryos while waiting for the results of preimplantation genetic testing for aneuploidy (PGT-A) and allowing more fresh transfers to occur. They also suggest patients could save money by not paying to store non-viable embryos.

However, research published last year indicates that PGT-A does not necessarily improve IVF outcomes (see BioNews 1123).