Question: Our surgeon performed an exploratory EGD for a patient with persistent abdominal pain, nausea, vomiting, and diarrhea. Following the procedure, the surgeon diagnosed the patient with unspecified infectious gastroenteritis. I submitted the symptoms in order of severity, so the nausea with vomiting was first, followed by the diarrhea, then the abdominal pain, then the gastroenteritis. The claim was denied. Why? Georgia Subscriber Answer: Improper ICD-10-CM code sequencing probably caused the denial. According to the ICD-10-CM Official Guidelines, the principal diagnosis should be sequenced first. The patient presented with a series of symptoms, but the provider determined the cause of those symptoms to be gastroenteritis, so that is what should be sequenced first. ICD-10-CM Official Guidelines Section II.A explains: “Codes for symptoms, signs, and ill-defined conditions from Chapter 18 are not to be used as principal diagnosis when a related definitive diagnosis has been established.” This means that you should first report the gastroenteritis, possibly as A09 (Infectious gastroenteritis and colitis, unspecified). The rest of the symptoms should then be reported in order of severity to help offer a comprehensive picture of the patient’s condition. If A09 is the best code to use for this encounter, beware the Excludes1 note, which says not to report A09 with Diarrhea NOS. That means you can’t report A09 and R19.7 (Diarrhea, unspecified) together. Also, per ICD-10-CM coding guideline I.C.18.a., because the physician made a diagnosis that implies stomach pain, you’ll only use an R10 code if the stomach pain is not “associated routinely with a disease process.” All these things considered, your new claim should end up looking something like this: