Final answer:
A manifestation code should not be used alone as a principal diagnosis. It should always be accompanied by a primary diagnosis code to accurately represent the main reason for the encounter or underlying condition being treated.
Step-by-step explanation:
A manifestation code should not be used as a principal diagnosis. A manifestation code is used to identify an underlying condition when a particular symptom or manifestation is being treated. It provides additional information about the nature of the patient's condition and helps in the treatment process. However, it should always be accompanied by a principal diagnosis code, which represents the main reason for the encounter or the underlying condition being treated.