Radiology Coding Alert

Read the fine print on payer policies to avoid unexpected bundling frustration

Sentinel node injection and imaging sounds simple enough, but toss in multiple injections, substances, and imaging techniques, and you've got a recipe for a potential coding disaster.

Simplify your task with these expert tips on applying the proper codes to the different sentinel node injection and imaging scenarios you may face.

Catch This Injection Unit Tip, Net an Extra $38

Sentinel node injection begins with the provider injecting a radioactive tracer near the tumor site. The tracer flows with the lymphatic fluid into the lymph nodes that are "downstream" from the tumor. The sentinel node is the first node in the chain, which makes it most likely to contain malignant cells if the cancer has spread.

The sentinel node absorbs the tracer, making it easy for the physician to locate it, says experienced radiology coder Stacy Gregory, RCC, CPC, of Tacoma, Wash.-based Gregory Medical Consulting Services.

Relevant code: The code that describes this injection procedure is 38792 (Injection procedure; for identification of sentinel node), which pays about $38.

Count units: Your payer may allow you to report a tracer injection and a dye injection separately. Example: Empire's sentinel node biopsy policy explains that you may report 38792 on two lines, one unit each, when one physician injects both the radioactive tracer and the vital dye. The key is that you report one unit per substance injected rather than one unit per injection. If the physician makes four separate tracer injections and does not inject the dye, you would report only one unit (see the LCD at www.empiremedicare.com/newypolicy/policy/l3473_final_guideline.htm).
 
Be on Guard

If your physician provides one 38792 service, and a surgeon provides a second 38792 on the same day, the payer will typically pay the first claim it receives and deny the second, Gregory says. Watch for the denial and appeal it with an explanation of the service.

Caution: You'll likely find that your payer bundles 38792 into the procedure described below.

Watch This Imaging Bundle Pitfall

Typically, the nuclear provider follows injection with lymphoscintigraphy. The provider uses a gamma camera to get dynamic, real-time images to map the tracer's path and sentinel node uptake, Gregory says, citing the AMA's CPT Assistant, December 1999.

The provider also gets static images at intervals until he can identify the sentinel node. Then the gamma camera gets multiple images from different angles to pinpoint the node's location, Gregory says. The provider marks the sentinel node's rough location on the skin so the surgeon can easily identify it.

Relevant code: Use 78195 (Lymphatics and lymph nodes imaging) to describe the nuclear medicine imaging of the site, called lymphoscintigraphy.

The AMA says lymphoscintigraphy includes the tracer injection, so you should not report 38792 when the provider performs lymphoscintigraphy, Gregory says, again citing CPT Assistant. 

Don't miss: A Correct Coding Initiative (CCI) edit makes 38792 mutually exclusive to 78195, and you can't override the edit with a modifier, Gregory says. 

Despite the AMA guidance, some payers say that you may report 38792 and 78195 separately. Example: Empire's policy says, "When lymphoscintigraphy is performed in advance of the surgical procedure to locate and mark the sentinel node(s), the injection and the lymphoscintigraphy procedures should be coded and reported separately by the physician performing these procedures. CPT code 38792 should be used for the injection procedure and code 78195 should be used for the lymphoscintigraphy" (www.empiremedicare.com/newypolicy/policy/l3473_final_guideline.htm).

Snag: As always, the CCI edits overrule the guidance contained in local coverage determinations, and this guideline specifically tells you to follow CCI edits.

Lesson: Report 38792 only when the provider performs tracer injection without also providing lymphoscintigraphy. If the provider performs both the tracer injection and the lymphoscintigraphy, report 78195 without 38792, unless your payer instructs you to ignore this particular CCI edit.

Don't miss: When a patient has a nuclear medicine scan one day and then returns on another day for a dye injection and node excision, you may report the dye injection (38792) for that second visit because it is not a component of the previous imaging procedure.

And remember to add modifier 26 (Professional component) if you're reporting only the professional component, Gregory says.

Don't Confuse Gamma Probe and Gamma Camera

Some providers may choose to use only a gamma probe--not a gamma camera--to locate the radioactive node, although this isn't very common, says Bruce Hammond, CRA, CMNT, chief operating officer of Diagnostic Health Services in Texas.

Relevant code: Locating the sentinel node with a probe does not count as lymphoscintigraphy, so you should report 38792 (injection) rather than 78195 (imaging) when the provider administers the injection and locates the node using a probe rather than a gamma camera.

Most often, providers use imaging to mark the node's location and then use a probe during surgery to verify the location because the node may shift slightly as the patient changes position, Hammond says. Your documentation may also show only imaging without probe use.

In both cases, you should report 78195 (imaging), not 38792 (injection).

Should You Tack on a Tracer Code?

Providers typically use Tc-99m Filtered Sulfur Colloid as the tracer, Hammond says.

"The 'filtered' part is significant," he says. "The cost differential is appreciable between filtered and non-filtered [sulfur colloid]."

Relevant code: If you bear the drug's cost, you should report it with A9541 (Technetium Tc-99m sulfur colloid, diagnostic, per study dose, up to 25 millicuries).