It is not possible to certify Qi components such as coils, shielding, and ICs. Compliance with the Qi specification can be determined only for products that are completely functional Qi transmitters or Qi receivers.
A product with components that have been used succesfully in a Qi Certified product is not automatically compliant. The use of different housing materials, different locations of coils and shielding, even differences in firmware can interfere with wireless power transfer.
Manufacturers of ICs usually demonstrate the suitability of their IC by certifying a demo product, the so-called "Evaluation Module". Products that use such IC must be tested for compliance. They are not automatically compliant.
A subsystem is a completely functional transmitter product, with coils, shielding, and control system assembled together. It can be operated and tested without any additional assembly or construction.
Products with an embedded Qi Certified subsystem need not be tested for compliance with the Qi specifucation, provided the subystem is integrated correctly. Be careful. Incorrect integration, with the wrong coil-surface distance for example, will make the product non-compliant and require testing of product.
You can find a list of Qi Certified Subsystems in the Qi Product Registration Database: "advanced search" and "Subsystem intended for integration into other products" = Yes.
A Tx product can be Qi Certified as a "Subsystem intended for integration in other products" only when it meets these criteria:
Products that contain a receiver subsystem, or module, must always be re-tested because materials used in the receiver product are likely to influence foreign object detection.