Final answer:
Chapter 18 of the ICD codes is used when a more precise diagnosis is not available for any other reason. It is used when no more specific diagnosis can be made after investigation, or when a patient fails to return and all you have is a provisional diagnosis. These codes are used by medical professionals for various purposes such as ordering laboratory tests, prescribing treatments, assigning codes for procedures performed, and processing claims for reimbursement by insurance companies.
Step-by-step explanation:
Chapter 18 of the ICD (International Classification of Diseases) codes is used when a more precise diagnosis is not available for any other reason. It is used when no more specific diagnosis can be made after investigation, or when a patient fails to return and all you have is a provisional diagnosis. These codes are used by medical professionals for various purposes such as ordering laboratory tests, prescribing treatments, assigning codes for procedures performed, and processing claims for reimbursement by insurance companies.