These ICD-9 conventions are the most applicable:
For accurate reporting of ICD-9-CM
diagnosis codes, the documentation should describe the patient's condition, using terminology which includes specific diagnoses as well as symptoms, problems, or reasons for the encounter. There are ICD-9-CM codes to describe all of these.
Code all documented conditions that coexist at the time of the encounter/visit, and require or affect patient care treatment or management. Do not code conditions that were previously treated and no longer exist. However, history codes (V10-V19) may be used as secondary codes if the historical condition or family history has an impact on current care or influences treatment. (Outpatient, if visit is unrelated to follow-up of resolved condition)
Previous conditions
If the physician has included a diagnosis in the final diagnostic statement, such as the discharge summary or the face sheet, it should ordinarily be coded. Some physicians include in the diagnostic statement resolved conditions or diagnoses and status-post procedures from previous admission that have no bearing on the current stay. Such conditions are not to be reported and are coded only if required by hospital policy.
However, history codes (V10-V19) may be used as secondary codes if the historical condition or family history has an impact on current care or influences treatment. (Inpatient only)
Aftercare visit codes cover situations when the initial treatment of a disease or injury has been performed and the patient requires continued care during the healing or recovery phase, or for the long-term consequences of the disease. The aftercare V code should not be used if treatment is directed at a current, acute disease or injury, the
diagnosis code is to be used in these cases. Exceptions to this rule are codes V58.0, Radiotherapy, and V58.1, Chemotherapy. These codes are to be first listed, followed by the diagnosis code when a patient's encounter is solely to receive radiation therapy or chemotherapy for the treatment of a neoplasm. Should a patient receive both chemotherapy and radiation therapy during the same encounter code V58.0 and V58.1 may be used together on a record with either one being sequenced first.
Certain aftercare V code categories need a secondary
diagnosis code to describe the resolving condition or sequelae, for others, the condition is inherent in the code title.
The follow-up codes are for use to explain continuing
surveillance following completed treatment of a disease,
condition, or injury. They infer that the condition has been
fully treated and no longer exists. They should not be
confused with aftercare codes which explain current
treatment for a healing condition or its sequelae.
Follow-up
codes may be used in conjunction with history codes to
provide the full picture of the healed condition and its
treatment. The follow-up code is sequenced first, followed
by the history code.
A follow-up code may be used to explain repeated visits.
Should a condition be found to have recurred on the follow-
up visit, then the
diagnosis code should be used in place of
the follow-up code.The follow-up V code categories:
V24 Postpartum care and evaluation
V67 Follow-up examination
Hope that's helpful!