Vitamin Companies

I heard that many manufacturers of vitamins status thing on their labels for content, but when tested it turns out that they starved their claims, where can I check to see if my vitamins are tested for accuracy?

There are three main that you often see referenced. Consumer Labs is one of the companies announcing major testing companies that pass / fail, but they do not test all the products you get a limited range listed.
Because of this, major companies will want to see listed are GMP (Good Manufacturing Practices) or USP (U.S. Pharmacopoeia), as those are the main quality assurance organizations (USP is for the United States, GMP for the United States and the world). If a company has a reference to one of these, you can be assured that you get a good quality product. Good luck and I hope I helped!