Question: The surgeon treated a patient with De Quervain’s tendinitis. So after an injection into the tendon sheath, I coded 20551. My claim was denied. What did I do wrong? Utah Subscriber Answer: The code you want to use is 20550 (Injection[s]; single tendon sheath, or ligament, aponeurosis [e.g., plantar “fascia”]). The code you used is 20551 (Injection[s]; single tendon origin/insertion) is incorrect because it focuses on the wrong site of injection. When orthopedists treat De Quervain’s tendinitis with injections, they focus on parts of the wrist. However, your decision on what code to use depends on small differences of the site of the injection. In your case, the injection is in the tendon sheath, meaning that the alternative tendon code does not accurately describe the surgeon’s work. Site of the injections always determines your code. Since De Quervain’s tendinitis largely affects the tendon sheath as opposed to the joint or tendon itself, the orthopedist’s intention is to work solely in the affected area. As always, keep back up documentation to confirm this procedure. Other codes exist that specifically state De Quervain’s disease. These codes, however, are only used when your surgeon’s injections fail to relieve the patient’s malady. For these cases, you should look to codes like 25000 (Incision, extensor tendon sheath, wrist [e.g., deQuervains disease]) or the more involved 25118 (Synovectomy, extensor tendon sheath, wrist, single compartment) if the more conservative injections fail. Otherwise, stick to the code 20550. Finish off your code with M65.4 (Radial styloid tenosynovitis [de Quervian]), and you will have a successful code to submit.