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Find out the differences between NCS and EMG tests.

The carpal tunnel is a narrow passageway in the wrist, about an inch wide. Carpal tunnel syndrome (CTS) occurs when the tunnel becomes narrowed or when the tissue surrounding the flexor tendons swells, putting pressure (compression) on the median nerve and reducing its blood supply. A patient who suffers from CTS usually complains of numbness, tingling sensation, pain and weakness in the hand and wrist area due to this abnormal pressure on the nerve.

Read on to learn about the condition, diagnostic procedures, and the CPT^® codes needed to complete your CTS-related claims.

Understand Which Tests Are Ordered to Diagnosis CTS

Initial evaluation by the hand surgeon will include a careful examination of the patient’s hand and wrist. This will include performing certain physical tests such as the Tinel’s sign, which involves the hand specialist tapping along the median nerve on the palm side of the wrist and hand to see if it causes any “pins and needles” sensation into the fingers. If the sensation is noted, a patient has a positive Tinel’s sign and is diagnosed with CTS.

Providers can also order electrodiagnostic tests to evaluate the patient’s condition, which include:

• Nerve conduction studies (NCS): Measures the signals travelling in the nerves of the hand and arm and can detect when a nerve is not conducting its signal effectively
• Electromyogram (EMG): Used to measure the electrical activity in muscles and is indicative of any nerve or muscle damage

The CPT^® code book features multiple codes reserved for reporting NCS and EMG tests. Each procedure is separated into different sections of the code book. The NCS codes differ in how many studies were performed at the time of the test, for example:

• 95907 (Nerve conduction studies; 1-2 studies)
• 95909 (...  5-6 studies)
• 95910 (... 7-8 studies)

According to the CPT^® guidelines, “Codes 95907-95913 describe nerve conduction tests when performed with individually placed stimulating, recording, and ground electrodes.”

Physicians may perform EMG tests without NCS or in conjunction with NCS on the same day. An example of a code that covers EMG performed with NCS is +95886 (Needle electromyography, each extremity, with related paraspinal areas, when performed, done with nerve conduction, amplitude and latency/velocity study; complete, five or more muscles studied, innervated by three or more nerves or four or more spinal levels (List separately in addition to code for primary procedure)).

You’ll assign add-on codes from +95885 to +95887 in conjunction with 95907-95913 when the provider performs EMG with NCS.

The CPT^® guidelines state that +95885 and +95886 may only be reported once per extremity, and that the codes “can be reported together up to a combined total of four units of service per patient when all four extremities are tested.”

Let documentation be your guide for code selection. NCS codes are chosen based upon the number of nerve conduction studies performed, and EMG codes are selected based upon the number of muscles studied. Use Appendix J in the CPT^® code book as a reference. When assigning a diagnosis, consult your local coverage determination (LCD) for guidance.

Imaging: Ultrasounds can be recommended to evaluate the median nerve for signs of compression. The high-frequency sound waves help create pictures of the bone and tissue.

Examine This E/M Scenario

Scenario: A 45-year-old patient comes in for a follow-up evaluation and management (E/M) appointment for their CTS. The patient complains of persistent numbness and tingling in the right hand, and conservative management strategies have not been effective. During the visit, the provider performs a detailed history, examination, and discusses the condition, potential treatment options, and answers questions. The physician also performs an ultrasound (US) of the right hand to assess the median nerve and surrounding structures.

In the scenario above, you’ll assign an appropriate evaluation and management (E/M) code along with 76882 (Ultrasound, limited, joint or focal evaluation of other nonvascular extremity structure(s) (eg, joint space, peri-articular tendon[s], muscle[s], nerve[s], other soft-tissue structure[s], or soft-tissue mass[es]), real-time with image documentation).

You’ll also need to append the appropriate laterality modifier, such as RT (Right side), and assign a diagnosis code based on the provider’s documentation. Also, since you’re billing an E/M CPT^® code along with the US, append 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) to the E/M code show the E/M visit was done as a significant and separately identifiable service from the same-day US.

When reporting 76882, the documentation should include the following: the specific anatomical structure(s) evaluated, detailed description of the findings for each structure examined, permanently recorded images with proper labeling, and a written report outlining the reason for the exam and interpretation of the ultrasound findings. It is best practice to verify payer-specific guidelines for additional documentation requirements.

Next month, we’ll examine nonsurgical and surgical CTS treatments and which diagnosis codes to report for CTS patients.

Misty Smith, CPC, COSC, AAPC Subject Matter Expert