I am worried that if I use V67.59, the insurance company won't know which diagnosis is resolved and why the physician ordered the lab work.
Answer: If, at the time of the encounter, the condition is not resolved (or the FP isn't sure it's resolved), you should code the condition.
If the condition has resolved, you should use the V67 series, such as V67.59, Follow-up examination, following other treatment; other, to indicate that the visit is for surveillance only.
Even though ICD-9 coding guidelines require using V67.xx alone, some payers may want you to list the original diagnosis in addition to the follow-up examination code. You should check with the insurance company for its policy.
For instance, in your case, an insurer may want to see the interstitial fibrosis diagnosis (516.3, Idiopathic fibrosing alveolitis) and/or the anemia code (such as 285.0, Sideroblastic anemia, which includes "secondary drug-induced anemia due to disease") with V67.59.
Sequence the V code after the resolved illness - once again, check with the payer. Submitting 516.3, 285.0, V67.59 with 99212-99215 (Office or other outpatient visit for the evaluation and management of an established patient ...) would indicate that the physician determined the patient still has interstitial fibrosis but no longer has anemia.