1.The difference between the official coding guidelines for using V codes in an inpatient and outpatient setting is the V guidelines for outpatient setting indicates code sequencing for physician office and clinic encounters. V codes also may be used as the principal and secondary diagnosis in the inpatient setting compared to those that may be used as the first listed or secondary diagnosis in the outpatient setting. The most important difference in the official guidelines of V codes is that the definition of principal diagnosis applies only to inpatients in acute, short-term, general hospitals. This means that the v coding guidelines for inconclusive diagnoses were developed for inpatient reporting and do not apply to outpatients. Because diagnoses are often not established at the time of the initial outpatient encounter or visit, this is an extremely important guideline when using v codes. In many outpatient cases, the diagnosis v code for a presenting sign or symptom must be assigned because a definitive diagnosis has not yet been determined.