Leukocyte Scan, NM & Radiolabeled, Indium/Tagged Scintigraphy, Procedure & CPT Code

Content:

• What is Leukocyte Scan?
• Leukocyte Scan in Nuclear Medicine (NM) & Radiolabeled Imaging
• Indium/Tagged Scintigraphy
• Leukocyte Scan Procedure
• Leukocyte Scan CPT Code

What is Leukocyte Scan?

A leukocyte scan, also known as a white blood cell (WBC) scan, is a specialized nuclear medicine test used to detect infections and inflammatory conditions inside the body. It works by tagging the patient’s own white blood cells with a small amount of radioactive material, which can then be tracked using imaging technology. Because leukocytes naturally migrate to areas of infection or inflammation, this scan highlights the specific sites where such activity is taking place.

This diagnostic method is especially helpful for cases where the location of an infection is uncertain or hidden, such as in bones, joints, or implanted medical devices. Doctors often use it when other imaging techniques like X-rays, MRI, or CT do not provide enough clarity. By giving a functional image of the immune system at work, the leukocyte scan provides a highly targeted way to diagnose hidden or complicated infections.

Leukocyte Scan in Nuclear Medicine (NM) & Radiolabeled Imaging

In nuclear medicine, leukocyte scans belong to a category of imaging tests that use radiolabeled substances to study physiological functions of the body. The process involves drawing a sample of the patient’s blood, isolating white blood cells, and tagging them with a safe radioactive tracer. Common tracers include Indium-111 and Technetium-99m, which are both widely used due to their effective imaging properties. After reinjecting the tagged cells back into the patient, a gamma camera detects the radiation they emit, producing detailed images of their distribution in the body.

The radiolabeled leukocyte scan is especially valuable in identifying infections that are not visible with standard imaging. For example, it helps distinguish between infection and sterile inflammation, guiding doctors to choose the correct treatment. It is also considered more specific than many other nuclear imaging tests because it directly visualizes the migration of the immune system’s own infection-fighting cells.

Indium/Tagged Scintigraphy

Indium-111 tagged leukocyte scintigraphy is one of the most common forms of this scan. In this process, the patient’s white blood cells are tagged with Indium-111, a gamma-emitting isotope. The tagged cells circulate through the bloodstream and naturally accumulate at sites of infection. Imaging is performed at different intervals, typically a few hours and up to 24 hours after reinjection, providing high-quality diagnostic information.

This technique is particularly useful in cases of suspected osteomyelitis (bone infection), vascular graft infections, and infections involving prosthetic devices. Tagged leukocyte scintigraphy offers high sensitivity and specificity, making it a gold-standard option for complex infection imaging. While it requires more preparation time compared to some nuclear scans, its accuracy and clinical usefulness make it a valuable diagnostic tool.

Leukocyte Scan Procedure

The leukocyte scan procedure usually begins with drawing a small amount of blood from the patient. Laboratory specialists then separate the white blood cells and mix them with a radioactive tracer such as Indium-111 or Technetium-99m. After incubation, the radiolabeled cells are reinjected into the patient’s bloodstream. Over the next several hours, these cells travel throughout the body and accumulate in areas where infection is present.

After enough time has passed, the patient undergoes imaging with a gamma camera or SPECT system. Multiple images are taken at different time intervals to track the movement and concentration of the tagged white blood cells. The test may last several hours and sometimes requires follow-up scans. Patients are generally able to go home the same day, and the procedure is considered safe, with minimal radiation exposure.

Leukocyte Scan CPT Code

In medical billing, the Current Procedural Terminology (CPT) code for a leukocyte scan helps standardize reimbursement and documentation. The commonly used CPT code for an Indium-111 leukocyte scan is 78806, which refers to radiopharmaceutical localization of infection with planar imaging. When single-photon emission computed tomography (SPECT) imaging is added, the code 78807 may be used.

These codes are important for healthcare providers to ensure accurate billing and insurance claims. Hospitals and imaging centers typically rely on them to document the type of scan performed. It is always advisable for patients to confirm with their providers and insurers which specific CPT codes are applied to their procedure, as variations may exist depending on the type of radiotracer used and whether advanced imaging techniques are included.