ED Coding and Reimbursement Alert

Labs, X-rays could be part of ED E/M.

Arthrocentesis, commonly known as joint drainage or joint injection, is routinely performed in emergency departments (EDs). This procedure helps diagnose various joint-related conditions and deliver therapeutic treatments.

Sometimes, the best way to see how to code in action is to see it used in a coding scenario. This clinical case study should give you vital insight as to how an arthrocentesis encounter might occur in your ED.

Check Out This Clinical Example

Consider the following scenario, in which a patient requires arthrocentesis:

A patient reports to the ED with a sudden onset of acute pain and swelling in the right knee; they first noticed the pain two days ago, and there is no history of injury in the knee. The patient describes the pain in their knee as throbbing, which intensifies with movement; they rate the pain as 8 out of 10 in severity.

Upon examination, the right knee demonstrates significant joint effusion, erythema, and warmth. The range of motion in the knee is notably restricted due to pain and swelling, though no rash or signs of lymphadenopathy are observed. Other systemic examinations did not reveal any abnormalities.

An X-ray of the right knee shows no acute fractures, dislocations, or signs of degenerative issues. Additional lab tests, including complete blood count (CBC), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), indicate no signs of infection.

Considering the clinical observations and test results, the ED physician performs an arthrocentesis on the right knee to remove synovial fluid from the joint. This procedure would be recorded in the ED chart with a procedure note similar to the following:

Procedure Note:
Preparation: Knee prepped, draped sterilely, cleansed with chlorhexidine. 
Approach: Lateral suprapatellar, avoiding patellar tendon. 
Anesthesia: 5mL of 1% lidocaine. 
Procedure: 18-gauge needle used to aspirate joint fluid, characteristics noted and sent for lab analysis
Closure: Needle removed, site compressed, sterile dressing applied. 
Outcome: Procedure well-tolerated, minimal blood loss, successful fluid collection, no vascular injury. 

In the procedure note listed above, the synovial fluid analysis revealed the presence of monosodium urate (MSU) crystals, which are characteristic of gout. The final diagnosis was documented as acute gouty arthritis, and the patient was discharged with a prescription for 800 mg of ibuprofen every six to eight hours as needed.

Remember: When the time comes to choose a diagnosis code, you will only code for the final diagnosis the physician reached (acute gouty arthritis). You don’t need to code the patient’s reporting symptoms — pain and swelling in the knee, joint effusion, erythema, range of motion restriction — because the ED physician was able to reach a definitive diagnosis.

Coders Count on Physicians to Document Key Elements

Correctly coding for arthrocentesis can be intricate. It is critical for the ED physician to clearly document the relevant details of the procedure, and equally important for coders to know the specific elements to look for in the documentation. Accurate coding is contingent upon two main factors: the type of joint or bursa involved and whether ultrasound (US) guidance was utilized during the procedure.

For smaller joints, such as those in fingers or toes, the available CPT^® code selections are 20600 (Arthrocentesis, aspiration and/or injection, small joint or bursa (eg, fingers, toes); without ultrasound guidance) and 20604 (… with ultrasound guidance, with permanent recording and reporting).

For procedures involving intermediate joints such as the wrist, elbow, temporomandibular joint (TMJ), etc., use 20605 (Arthrocentesis, aspiration and/or injection, intermediate joint or bursa (eg, temporomandibular, acromioclavicular, wrist, elbow or ankle, olecranon bursa); without ultrasound guidance) or 20606 (… with ultrasound guidance, with permanent recording and reporting).

When the ED physician performs drainage on a major joint such as the shoulder, hip, or knee, the corresponding CPT^® codes are 20610 (Arthrocentesis, aspiration and/or injection, major joint or bursa (eg, shoulder, hip, knee, subacromial bursa); without ultrasound guidance) and 20611 (… with ultrasound guidance, with permanent recording and reporting).

Coding the Case

Now, let’s see what the coder should choose to report on the claim, based on the encounter notes and arthrocentesis code list.

With the notes, final diagnosis, and choice of arthrocentesis CPT^® codes, the coder now has everything they need to assign the appropriate codes for the service.  The procedure would be reported with CPT^® code 20610. The best practice would be to attach the modifier RT (Right side) to 20610 to specify laterality.  

As for the evaluation and management (E/M) portion of the encounter, the documentation supports moderate cost of poor quality analysis (COPA), moderate data and moderate risk; therefore, the applicable E/M code would be 99284 (Emergency department visit for the evaluation and management of a patient, which requires a medically appropriate history and/or examination and moderate level of medical decision making). As the E/M is being reported with a procedure, modifier 25 (Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professional on the same day of the procedure or other service) would be attached to the 99284 E/M code.

Don’t forget the Dx code: The final diagnosis of acute gouty arthritis would be coded M10.061 (Idiopathic gout, right knee). Append M10.061 to 20610 and 99284 to represent the patient’s gout.

Todd Thomas, CPC, CCS-P, President, ERcoder, Inc.