CPT® Code 78191

1. Indications

The platelet survival study is indicated for various clinical scenarios where the evaluation of platelet function and lifespan is necessary. The following conditions may warrant this procedure:

• Thrombocytosis - This condition, characterized by an elevated platelet count exceeding 400,000 per microliter, may be investigated to determine the underlying cause, which could include anemia, cancer, inflammation, or infection.
• Thrombocytopenia - A decreased platelet count below 100,000 per microliter may necessitate this study to identify potential causes such as drug effects, inherited disorders, malignancies like leukemia or lymphoma, kidney dysfunction, or excessive alcohol consumption.
• Monitoring Disease States - The test can be used to monitor the effects of various disease states on platelet survival, providing insights into the patient's condition and guiding treatment decisions.
• Evaluation of Transfusion Procedures - The platelet survival study may be employed to assess the effectiveness of platelet collection and storage procedures, ensuring that transfused platelets maintain their functionality.

2. Procedure

The procedure for conducting a platelet survival study involves several key steps that ensure accurate measurement of platelet lifespan. The following outlines the detailed procedural steps:

• Step 1: Blood Sample Collection - A blood sample is obtained from the patient through venipuncture or by drawing from an intravenous line (heplock). This initial step is crucial for establishing a baseline platelet count, which will be used for comparison throughout the study.
• Step 2: Centrifugation - After the blood sample is collected, it is subjected to centrifugation. This process separates the components of the blood, allowing for the isolation of platelet-rich plasma, which contains the platelets necessary for the subsequent steps of the study.
• Step 3: Addition of Radioisotope Tracer - The isolated platelets are then treated with a radioisotope tracer, specifically 111-Indium Oxine. This tracer labels the platelets, enabling their tracking within the patient's bloodstream.
• Step 4: Incubation - Following the addition of the tracer, the platelets are incubated to allow for adequate binding of the radioisotope to the platelets, ensuring that they can be effectively monitored during the study.
• Step 5: Re-injection - After incubation, the labeled platelets are injected back into the patient. This step is essential for initiating the monitoring phase of the study.
• Step 6: Blood Draws at Intervals - Blood samples are drawn at specified intervals—20 minutes, 2 hours, 3 hours, 4 hours, and daily for a period of 1 to 10 days. These samples are analyzed to determine the survival rate of the platelets over time, providing valuable data on their lifespan and functionality.

3. Post-Procedure

After the completion of the platelet survival study, patients may be monitored for any immediate reactions to the procedure, particularly in relation to the re-injection of the labeled platelets. It is important to observe for any signs of adverse effects or complications. The results of the study will be analyzed to assess platelet survival, and the findings will be documented for further evaluation by the healthcare provider. Depending on the results, additional follow-up tests or interventions may be recommended to address any identified issues related to platelet function or count. Patients should be informed about the importance of follow-up appointments to discuss the results and any necessary treatment plans.