When an ED physician uses the verbage "most likely represents ..." would this be considered like a probable and not codeable--outpatient rules. Physician documented his Diagnosis--Allergic reaction. Physician documented in his Plan--considerations for the reaction could be due to some plums the patient had eaten or most likely due to patient's medication. I coded as allergic reaction, nos--995.3, since physician did not know for sure what the patient was allergic to. An auditor coded as adverse effect of correct medicinal substance properly administered--995.29 plus E code.