Chromosomal microarray testing (CMA) generally aids paediatric genetic diagnosis. However, pre-CMA counselling is important as results can be ambiguous, generate uncertainty and raise ethical issues. We developed standards for counselling and giving families results; using these we evaluated practice for children seen by the Auckland Developmental Paediatric team in 2011. Pretest discussion was documented in 14 of 28 subjects and potential outcomes in 4of 28. 8 of 28 received information leaflets, 1 of 28 gave signed consent. 3 of 3 with abnormal results and 4 of 5 with variants of unknown significance (VOUS) were offered clinical genetics referral. 8 of 20 families with normal results were written to; two with abnormal results were informed face-to-face and one in writing; most VOUS were communicated by phone, voicemail or letter.Conclusion:
CMA testing requires clear patient information sheets and in-depth pretest discussion for informed consent, timely feedback of results and genetics referral as appropriate. Authoritative guidelines and training are needed to strengthen CMA counselling.