Microarray as a first genetic test in global developmental delay: a cost-effectiveness analysis.

AIM Microarray technology has a significantly higher clinical yield than karyotyping in individuals with global developmental delay (GDD). Despite this, it has not yet been routinely implemented as a screening test owing to the perception that this approach is more expensive. We aimed to evaluate the effect that replacing karyotype with array-based comparative genomic hybridization (aCGH) would have on the total cost of the workup for GDD. METHOD We evaluated the cost-effectiveness of aCGH compared with karyotyping by retrospectively analysing the cost of workup in a cohort of 114 children (69 males; 45 females) representing a consecutive series of children diagnosed with GDD. RESULTS The average increase in cost if aCGH had been performed instead of karyotyping as a first test was $442 per individual when performed by a private company (98% confidence interval $238-604). In contrast, $106 (98% confidence interval -$17 to $195) would have been saved if aCGH was performed locally in a laboratory already possessing the required technology. The incremental cost per additional diagnosis was estimated to be $12,874 if aCGH was performed in a private laboratory, but <$1379 if performed locally. (Costs reported in Canadian dollars, using 2010 prices.) INTERPRETATION aCGH would be cost-effective as a first genetic test in the clinical evaluation of individuals with GDD.