Preparation of clearance opinions is actually an examination of novelty.
An examination for patent novelty is usually carried out in the framework of patent examination. Patent novelty is a legal property of an object meaning that it can be freely used in a specific country without the risk of violating of exclusive rights of legally effective patents on its territory. So the subjects having patent novelty are those that are not subject to patents for inventions, useful models or industrial designs issued by an authorized patent office and valid in the territory of that country. In addition, objects can not violate registered trademarks, as well as brand names and indications of the origin of goods.