Question: A lot of cancer patients come into our office with complaints of fatigue. I'm not even sure where to start looking in ICD-10-CM for that code. How do I make sure that I report this correctly? Connecticut Subscriber Answer: The two codes you have at your disposal are R53.81 (Other malaise) and R53.83 (Other fatigue). Before you ask which code to use, just know there is no clear distinction between the terms malaise and fatigue. It is very possible for you to choose either one and not receive any kickback from auditors. Few codes are interchangeable, but R53.81 and R53.83 appear to address the same issues. Think about the two in this way. If you went to work, had a hard-strenuous day, you would be tired from the activities of the day. You can call this fatigued. Now consider how you feel when you have a cold or the flu. At the end of the day, you're tired, but overall your energy was expended on the fact you're your body wasn't energized, and you feel 'run down' from the illness. You wouldn't be fatigued, rather you can describe the feeling as malaise. Hopefully, these examples can help you differentiate between the two. What might help you guide your coding decision is if you take a look at the oncologist's documentation. You should check to see if they clearly label the malady as fatigue or malaise. This can help you align your code with the documentation for consistency. Do not use code R53.82 (Chronic fatigue, unspecified) if the oncologist has not reported the condition as chronic. Typically, the term chronic refers to any complaint lasting more than three months. In most cases when a patient complains about fatigue, especially during the course of cancer treatment, the malady is fairly current. This excludes the use of the chronic code.