CPT® Code 78122

Whole blood volume determination, including separate measurement of plasma volume and red cell volume (radiopharmaceutical volume-dilution technique)

The CPT® Code 78122 refers to a laboratory test known as whole blood volume determination, which includes the separate measurement of plasma volume and red cell volume using a radiopharmaceutical volume-dilution technique. This procedure is essential for accurately assessing the total blood volume (TBV) in patients, particularly those with conditions that may lead to abnormal blood volume, such as chronic illnesses or acute trauma. The test is particularly valuable in evaluating a patient's risk status prior to surgical procedures, as it provides critical information regarding their circulatory health. Additionally, it plays a significant role in diagnosing and managing various medical conditions, including heart failure, renal failure, syncope, polycythemia, hypertension, and chronic fatigue. The methodology typically involves the use of radiolabeled tracers, specifically technetium 99m red blood cells (Tc-99m RBC) and technetium-99m (99mTc) human serum albumin (HSA), which are injected into the patient to facilitate the measurement of blood volume. This comprehensive approach ensures that healthcare providers can make informed decisions based on precise blood volume assessments.