Do you recommend genetic testing after a patient on clopidogrel has a stroke based on the results of the CHANCE-2 trial?

No, the data from CHANCE-2 (Wang et al., PMID 34708996) was based on a strictly Asian population and results need to be validated elsewhere for it to change practice.

Regarding genetic testing for slow clopidogrel metabolizers, it is probably not a bad idea in selected cases especially in patients of Asian descent as the incidence is higher there.

Currently, genetic testing is a reasonable approach to identifying the subgroup of patients who would most benefit from ticagrelor versus clopidogrel after an acute non-cardioembolic stroke or high-risk TIA. However, this strategy is not justified if the goal is to control costs. The current costs f...