CPT® Code 78122

1. Indications

Whole blood volume determination is indicated for various clinical scenarios where accurate assessment of blood volume is crucial. The following conditions may warrant this procedure:

• Chronic Illness Patients with chronic illnesses may experience abnormal blood volume, necessitating evaluation to guide treatment.
• Acute Trauma In cases of acute trauma, determining blood volume can help assess the severity of the patient's condition and inform management strategies.
• Surgical Risk Assessment Prior to surgery, evaluating a patient's blood volume can assist in determining their risk status and readiness for the procedure.
• Heart Failure This test can aid in diagnosing and managing heart failure by providing insights into the patient's circulatory status.
• Renal Failure In patients with renal failure, blood volume assessment can be critical for appropriate treatment planning.
• Syncope Patients experiencing syncope may require blood volume evaluation to identify underlying causes.
• Polycythemia The test can help in diagnosing polycythemia by measuring red cell volume.
• Hypertension Blood volume determination may be useful in understanding the factors contributing to hypertension.
• Chronic Fatigue In cases of chronic fatigue, assessing blood volume can provide valuable information regarding the patient's overall health.

2. Procedure

The procedure for whole blood volume determination involves several critical steps to ensure accurate measurement of blood volume components. The following outlines the procedural steps:

• Step 1: Patient Preparation The patient's height and weight are recorded to facilitate accurate calculations of blood volume. This information is essential for determining the ideal blood volume based on the patient's physical characteristics.
• Step 2: Establishing Venous Access Venous access is established to allow for the collection of blood samples and the administration of the radiolabeled tracers. This step is crucial for the subsequent phases of the procedure.
• Step 3: Baseline Blood Sample Collection A baseline blood sample is obtained from the patient prior to the injection of the radiopharmaceutical. This sample serves as a reference point for comparison after the tracer has circulated.
• Step 4: Injection of Radiolabeled Pharmaceutical The radiolabeled pharmaceutical, typically technetium 99m red blood cells (Tc-99m RBC) and technetium-99m (99mTc) human serum albumin (HSA), is injected into the patient. This tracer will circulate in the bloodstream and allow for the measurement of blood volume.
• Step 5: Circulation Period After the injection, the radiolabeled tracer is allowed to circulate within the body for a specified period. This allows for adequate distribution of the tracer throughout the blood volume.
• Step 6: Blood Sample Collection Post-Injection Following the circulation period, venipuncture is performed again to draw a blood sample. This sample will be analyzed to determine the dilution of the radiolabeled tracer.
• Step 7: Microhematocrit Measurement The microhematocrit is measured from the collected blood sample. This measurement is essential for calculating the red cell volume.
• Step 8: Centrifugation The remaining blood sample is centrifuged to separate the plasma from the red blood cells. This separation is necessary for accurate volume calculations.
• Step 9: Data Calculation Data from the patient sample is calculated using established formulas that compare the dilution factors from standardized samples of the radiolabeled tracer with ideal results based on the patient's height, weight, and hematocrit. This calculation provides the final assessment of whole blood volume, plasma volume, and red cell volume.

3. Post-Procedure

After the whole blood volume determination procedure, patients may be monitored for any immediate reactions to the radiopharmaceutical. It is important to ensure that the patient is stable and does not exhibit any adverse effects. The results of the blood volume assessment will be analyzed and interpreted by the healthcare provider, who will then discuss the findings with the patient and determine any necessary follow-up actions or treatments based on the results. Patients may be advised to resume normal activities unless otherwise directed by their healthcare provider. Additionally, any specific post-procedure care instructions should be provided to the patient to ensure their well-being following the test.