Assessing the unmet needs of genomic testing in Australia: a geospatial exploration

The role of genomic testing in rare disease clinical management is growing. However, geographical and socioeconomic factors contribute to inequitable uptake of testing. Geographical investigations of genomic testing across Australia have not been undertaken. Therefore, we aimed to investigate the geospatial distribution of genomic testing nationally between remoteness areas, and areas of varying socioeconomic advantage and disadvantage. We requested patient postcodes, age, and test type from genomic testing records from seven Australian laboratories for a 6-month period between August 2019 and June 2022. Postcode data were aggregated to Local Government Areas (LGAs) and visualised geospatially. Data were further aggregated to Remoteness Areas and Socio-Economic Index for Areas (SEIFA) quintiles for exploratory analysis. 11,706 records were eligible for analysis. Most tests recorded were paediatric (n = 8358, 71.4%). Microarray was the most common test captured (n = 8186, 69.9%). The median number of tests per LGA was 5.4 (IQR 1.0-21.0). Fifty-seven (10.4%) LGAs had zero tests recorded. Remoteness level was negatively correlated with number of tests across LGAs (rho = -0.781, p < 0.001). However, remote areas recorded the highest rate of testing per 100,000 populations. SEIFA score positively correlated with number of tests across LGAs (rho = 0.386, p < 0.001). The third SEIFA quintile showed the highest rate of testing per 100,000 populations. Our study establishes a foundation for ongoing assessment of genomic testing accessibility and equity and highlights the need to improve access to genomic testing for patients who are disadvantaged geographically or socioeconomically. Future research should include additional laboratories to achieve a larger representation of genomic testing rates nationally.