Not only is it standard procedure in recent pandemics for the US to make their own kits as the pother poster noted, but other developed countries do the same thing. China, Japan, Korea, and the UK all made their own kits too. These are just the countries I checked into. The WHO kit by the way is the one made by Germany, not some grand international super-kit. Imagine if it had been the faulty one.

And developed countries wouldn't actually use WHO kits, just the protocol to manufacture their own tests. The WHO distributes kits only to poor countries. Everyone still runs into the same issues ramping up production.