Gastroenterology Coding Alert

Question: I am getting a denial for an add-on code, saying it was not billed with the correct primary code. Is there a list online of add-on codes with their correspond-ing primary codes?Louisiana SubscriberAnswer: There is not a crosswalk for add-on codes. The CPT manual often lists the primary codes with which you are supposed to use the add-on code.For example, when you are looking to code +96570 (Photodynamic therapy by endoscopic application of light to ablate abnormal tissue via activation of photosensitive drug[s]; first 30 minutes [List separately in addition to code for endoscopy or bronchoscopy procedures of lung and esophagus]), the manual states beneath the code, "Use 96570, 96571 in conjunction with 331641, 43228 as appropriate."Similarly, when your physician treats a Crohn's patient with Remicade infusion that lasts longer than 90 minutes, you'll code +96415 (Chemotherapy administration, intravenous infusion technique; each additional hour [List separately in addition to code for primary procedure]). Under the code listing is an instruction to "use 96415 in conjunction with 96413" (Chemotherapy administration, intravenous infusion technique; up to 1 hour, single or initial substance/drug).