I know it may sound silly a tester conversing about passing the bar exam as that is something typically done by lawyers to see if they are fit to practice law in a specific jurisdiction. In my opinion, something like that should also be instated for software test professionals, it should not be location based but sector based.
The way I see it testers in different sectors have different competencies and ways of acting when they have to work in different sectors. For instance, in the embedded industry software has no front end, so you have to be way more technical than when you are employed within the public sector.
Every sector has its own specific criteria on which the judge certain professionals. So I think a general certification is needed so professionals amongst each other know what the other is talking about in general, but a tester who has him of her self-developed within the confines of the embedded industry must he or she learn about administrative process testing or is he or she better off learning more about white box testing or coding. Whilst a tester which has been taught to test administrative processes through the front end, should he or she learn about code complexity which they will never put into practice.
This is where a bar exam comes in particular well because now you can test if someone is fit to work in one sector or another. Of course it is not always as black and white as I write it down on my blog, but maybe just maybe it is something to consider.