ED Coding and Reimbursement Alert

Confirm medical necessity with a sharp diagnosis coding knowledge.

As most ED coders are aware, you can't prove medical necessity for your clinicians' services with CPT® codes alone - instead, it's the diagnosis codes that tell the insurer exactly why you had to perform the services you did.

Therefore, it's essential that you have a sharp and accurate knowledge of every diagnosis coding section in the ICD-10 manual. Read on and test yourself to see whether you can assign the most appropriate diagnoses to these services.

Question 1: A patient presents with complaints of chest pain and thinks he is having a heart attack. An EKG comes back normal, but a chest x-ray reveals "lung opacity and/or nodule," based on the radiologist's report. The ED physician refers the patient to a specialist for further evaluation. How can you code this?

What you should report: This question brings up several interesting considerations. Should you report a code for the chest pain, for the feared condition (heart attack), or for the "lung opacity and/or nodule?" While a coder may feel the inclination to send the report back to the provider for clarity, the ICD-10-CM guidelines explain what you should do when this coding scenario arises.

First, the 2018 ICD-10-CM Coding Guidelines address whether to code the feared condition (heart attack), and the answer is that you should not report that since the EKG was normal. "Do not code diagnoses documented as 'probable,' 'suspected,' 'questionable,' 'rule out,' or 'working diagnosis' or other similar terms indicating uncertainty," the Guidelines state in Section IV, Part H. "Rather, code the condition(s) to the highest degree of certainty for that encounter/visit, such as symptoms, signs, abnormal test results, or other reason for the visit."

Therefore, you should report the code for the primary reason the patient presented, which is the chest pain (for instance, R07.8, Other chest pain). You can follow that with the diagnosis code representing the radiologist's findings. But if you're torn about how to report "lung opacity and/or nodule" since it's ambiguous, look no further than the ICD-10 Guidelines once again.

According to Section II, part D, "In those rare instances when two or more contrasting or comparative diagnoses are documented as 'either/or' (or similar terminology), they are coded as if the diagnoses were confirmed and the diagnoses are sequenced according to the circumstances of the admission. If no further determination can be made as to which diagnosis should be principal, either diagnosis may be sequenced first."

Based on this explanation, you can consider the phrasing of "and/or" to be synonymous with "either/or" and therefore make the determination that you should code both diagnoses. Since there is no further elaboration as to the sequencing of the diagnoses, the determination of primary versus secondary diagnosis can be left up to your discretion. You will apply codes R91.1 (Solitary pulmonary nodule) for the nodule and R91.8 (Other nonspecific abnormal finding of lung field) for the opacity, in whichever order you'd like.

Question 2: A six-year-old patient presents due to dehydration from constant vomiting. The patient's mother tells you that the patient suffers from cyclical vomiting syndrome. Should you report the diagnosis as dehydration, vomiting, or cyclical vomiting syndrome?

What you should report: When patients present with this condition, their main complaint is almost always vomiting (R11.10), but since you know a more definitive diagnosis (cyclical vomiting syndrome), you shouldn't report R11.10. Instead, you'll first report dehydration as your main diagnosis code (such as E86.0), since that is specifically what the ED physician treated. Next, you'll report the code for the patient's disease, which is G43.A0 (Cyclical vomiting, not intractable) or G43.A- (Cyclical vomiting), depending on which code the physician believes is most accurate.

Question 3: The physician documents "hematoma of sternothyroid muscle" as the diagnosis. Which code applies to this?  

What you should report: If the patient presented without any additional information than what's listed above, you should code this under the assumption that the hematoma is not a result of trauma.

When it comes to hematoma diagnoses, the immediate first step to take is to determine whether or not an injury has occurred. Most coders might understandably search the ICD-10 index for Hematoma ⇒ muscle ⇒ code by site under Contusion. However, this is an example of why it's important to browse the entire index under a keyword before reaching a conclusion on the correct diagnosis. Immediately below Hematoma ⇒ muscle, you will find Hematoma ⇒ nontraumatic ⇒ muscle ⇒ M79.81 (Nontraumatic hematoma of soft tissue). M79.81 is the correct diagnosis code for a hematoma of the gluteus medius.

Look out: When handling diagnoses involving hematomas, context is absolutely key. If there's no context surrounding the diagnosis, it's safe to assume that a trauma did not occur. However, most experienced coders know that documentation of trauma is often ambiguous at best. Reference of a "fall" or "MVA" in the indication does not give the coder free rein to assume an injury has, in fact, occurred. In these cases, it's suggested that the coder send the report back to the physician for clarification. Otherwise, they will face one of the many classic coder's dilemmas, in which they are forced to apply a nontraumatic hematoma code to a hematoma that has (probably) occurred as a result of a fall or MVA.