An Australian study has found that a popular fertility test, available until 2013, significantly underestimated egg reserves.

Anti-Müllerian hormone (AMH) is used as a marker for ovarian reserve and, since 2011, the standard test for AMH was the Beckman Coulter Generation (Gen) II assay. However, in 2013, concerns were raised that it provided falsely low readings, leading it to be replaced with a revised version.

Now researchers at the fertility treatment organisation Genea have published a study that compared the original Gen II test and protocol with the revised test and protocol. The study measured serum AMH levels for 492 natural conception first trimester pregnant women aged between 20 and 44 years. The aim was not to directly define a level that reflects infertility, but rather to establish a fertile female reference range for the revised test – the first study to do so.

However, the authors found that the original protocol underestimated AMH levels by an average of 68 percent. The median AMH level recorded using the original protocol was 8.4 pmol/L compared with 14.2 pmol/L with the revised protocol.

Despite this, fertility specialists are however urging women who took the test between 2011 and 2013 not to panic.

The leader of the study and Genea medical director Professor Mark Bowman said: 'It's not really a test of fertility or a test that tells you how many eggs you have left – it's sometimes wrongly thought of as such. Anti-Mullerian hormone just gives you a rough idea of how many eggs are coming up for action each month, so it's a test of egg quantity, not of egg quality. And what it really does is help us decide which drugs might be the best to give to a woman who needs them.'

Professor Michael Chapman, the Vice President of the Fertility Society of Australia and Professor of Obstetrics and Gynaecology at the University of New South Wales, added that women could be reassured that current methods of testing had been proven to be appropriate and to give stable results. He also added however that 'there are other factors a fertility specialist considers beyond just this test'.

Professor Bowman has also urged women to resist 'wandering up' to a medical clinic and asking for the test without expert input because they may be unnecessarily panicked by the result.

The study was published in published in the Journal of Assisted Reproduction and Genetics.

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.