If you mean invalid CIs then you can define the required fields that need to exist for a CI to be valid and mark those fields as mandatory, if these attributes are missing the value then they won't be imported into CMDB. I would be cautious with this approach as you might be rejecting a lot of data.
Another better way is to mark the fields that you think needs to exists and mark them as recommended and run a health job to see how many CIs are invalid or doesn't have sufficient data.
