​A human error in processing at the cytogenetic laboratory of the Children’s Hospital at Westmead has resulted in four families receiving incorrect genetic test results.

NSW Health confirmed the nature of the error on December 13, after testing on a newborn baby did not match earlier prenatal test results.

Chief Health Officer Dr Kerry Chant said NSW Health has met with three of the four affected patients (the fourth has not been contactable so far) to advise of the error. Clinical counselling and support tailored to the circumstances of each patient will be provided, and we have established an external review.

“NSW Health offers its sincere apologies to the four families. As soon as we confirmed the error, we contacted each patient and their treating clinicians and provided full open disclosure,” Dr Chant said.

“While this is an isolated incident, we are nevertheless conducting an audit of other patients’ samples as part of the comprehensive, independent review underway.

“This is not a routine antenatal test. Microarray testing is a DNA test to identify chromosomal abnormalities, and is only undertaken when there is already a clinical suspicion of a possible genetic anomaly.”

Dr Chant said this is the first time an error of this kind has been reported at this cytogenetic laboratory since this test began in 2006.

“This is a very rare occurrence – since it came into operation, the cytogenetic lab has conducted close to 100,000 tests. This particular laboratory was given full accreditation as recently as 2015.

“The independent review will examine all systems and processes at the cytogenetic laboratory and compare these processes with international best practice. Any recommendations from the review to improve safeguards will be implemented at all three cytogenetic laboratories operated by NSW Health.

Dr Chant said the review and audit will be conducted by Honorary A/Professor Howard Slater, former Head of Cytogenetics, Victorian Clinical Genetics Services and Dr Chiyan Lau, Staff Specialist, Genetic Pathology, NSW Health Pathology.

Families who have concerns about their cytogenetic test, should talk to their GP or obstetrician in the first instance. More information is available on the Children’s Hospital Westmead hotline 1800 770 100.

The terms of reference for the review of cytogenetic testing and procedures can be found in review relating to cytogenetics testing and procedures.