Question: I-m trying to find a diagnosis code for giant papillary conjunctivitis. Since I can't find GPC specifically mentioned in the ICD9 manual, should I use the -other and unspecified- code 372.39?
Answer: For a diagnosis of giant papillary conjunctivitis, you should report ICD-9 code 372.14 (Chronic conjunctivitis; other chronic allergic conjunctivitis). Code 372.39 (Other and unspecified conjunctivitis; other) would not be an appropriate diagnosis code.
Why? You must code as specifically as possible. GPC is a chronic allergic form of conjunctivitis, sometimes caused by allergens attached to the contact lens. Because none of the other codes in the 372.1x series (Chronic conjunctivitis) describe GPC specifically, you must use the -other- code, 372.14.
Code 372.39 describes conjunctivitis less specifically than 372.14, since it makes no mention of the chronic and allergic nature of GPC. However, if the diagnosis were -conjunctivitis,- without further explanation, 372.39 would probably be appropriate.