CPT® Code 78140

1. Indications

The labeled red cell sequestration test is indicated for the following conditions:

• Hereditary Spherocytosis - A genetic condition characterized by the production of abnormally shaped red blood cells that are prone to destruction.
• Acquired Hemolytic Anemia - A condition where red blood cells are destroyed faster than they can be made, often due to external factors.
• Hemolytic Anemia due to Lymphoma or Leukemia - Anemia that occurs as a result of blood cancers, which can lead to increased destruction of red blood cells.

2. Procedure

The procedure for labeled red cell sequestration involves several detailed steps to ensure accurate results:

• Step 1: Blood Withdrawal - Blood is collected from the patient through venipuncture or via a heplock/intravenous line. This initial sample is used to obtain a baseline microhematocrit, which measures the proportion of blood volume that is occupied by red blood cells.
• Step 2: Tagging RBCs - The red blood cells are then tagged with the radioactive isotope tracer, Cr-51 Na Chromate. This tagging process allows for the tracking of the RBCs as they circulate through the body.
• Step 3: Injection of Tagged RBCs - After incubation, the tagged RBCs are injected back into the patient intravenously. This step is crucial for initiating the monitoring of RBC sequestration.
• Step 4: Scintillation Imaging - Starting 24 hours post-injection, the patient undergoes scintillation imaging using an uptake counting probe. This imaging continues daily for a total of 21 days. The probe is placed over the liver, spleen, precordium, or other suspected target sites to measure the activity of the tagged RBCs.
• Step 5: Marking the Skin - The patient's skin is marked with permanent ink to ensure that the same area is assessed consistently during each imaging session.
• Step 6: Specific Scanning Techniques - The liver is scanned along the midclavicular line while the patient is in a supine position. The precordium is scanned at the 3rd intercostal space at the left sternal border, also with the patient supine. The spleen is scanned at the 9-10th ribs with the patient in a prone position.
• Step 7: Interpretation of Results - After the imaging is completed, the physician interprets the scintigraphy images and provides a written report detailing the findings, which will assist in diagnosing any underlying conditions.

3. Post-Procedure

Post-procedure care for the labeled red cell sequestration test typically involves monitoring the patient for any immediate adverse reactions to the radioactive tracer. Patients may be advised to stay hydrated and report any unusual symptoms, such as pain or discomfort at the injection site. The results of the scintigraphy will be reviewed by the physician, who will discuss the findings with the patient and outline any necessary follow-up actions or treatment options based on the results.