Difference Between SDP and RDP

The key difference between SDP and RDP is that SDP is a type of platelet transfusion in which platelets are collected by apheresis from a single donor. Meanwhile, RDM is a type of platelet transfusion in which platelets are obtained from different qualified donors and then combined to transfuse to the patient.

Platelets are small cell fragments found in our blood. It is the major component that prevents bleeding. When there is a rupture in the blood vessel, platelets form blood clots to stop further bleeding. The normal platelet count in our blood ranges from 150,000 to 450,000 per microliter of blood. Low platelet count can lead to severe bleeding. If not treated, it can be a fatal problem. Platelet transfusion is considered an effective therapy for the prevention and treatment of bleeding. Therefore, platelets are transfused to patients with low platelet count or platelet dysfunction. Platelets can be transfused either by single donor platelets (SDP) or random donor platelets (RDP).

CONTENTS

1. Overview and Key Difference
2. What is SDP 
3. What is RDP
4. Similarity Between SDP and RDP
5. Side by Side Comparison – SDP vs RDP in Tabular Form
6. Summary

What is SDP?

Single donor platelet is a procedure of platelet transfusion. In this method, platelets are collected by a platelet aphaeresis machine from a single donor. Hence, this method is also known as plateletpheresis. The donor is hooked up to the apheresis machine in order to remove blood. Only the platelets are extracted. The remaining blood component, including blood cells and plasma, is returned to the donor.

Since this method can collect sufficient amounts of platelets from a single donor, the necessity of combining platelets from other donors is avoided. Therefore, SDP shows less infectious risk and less risk of HLA alloimmunization. Moreover, SDP is better than RDP in leucoreduction, decreasing the risk of septic platelet transfusion reactions, reducing exposures to multiple donors and transfusion frequency, and treating alloimmunization. However, SDP is more costly than RDP since it includes expenses for the equipment.

What is RDP?

Random donor platelets or RDP is another method of platelet transfusion. In this method, platelets are prepared from donated blood from any qualified donors. Generally, this method uses whole blood collected in traditional blood donation programmes. Whole blood collected from several random donors is combined (pooled) and centrifuged to prepare a single transfusion. Within 4 hours after pooling, the platelets should be transfused to the patient. It is done through a bedside leukocyte reduction filter.

However, this process increases the risk of diseases transmitting to the patient. Since pooled platelets should be transfused promptly, it limits the testing for bacterial contaminations as well. Nevertheless, RDP is cost-effective compared to SDP since it does not require equipment.

What are the Similarities Between SDP and RDP?

• SDP and RDP are two types of platelet transfusion methods.
• Both methods are effective.
• Post-transfusion increment, platelet survival and hemostatic effect are similar in both methods.
• Both have a shelf life of five days.

What is the Difference Between SDP and RDP?

SDP is a platelet transfusion method in which platelets are prepared from a single donor by an apheresis machine. RDP is a platelet transfusion method in which platelets are prepared by centrifuging the whole blood collected from four to five donors and pooling the platelets. So, this is the key difference between SDP and RDP.

The below infographic lists the main differences between SDP and RDP in tabular form.

Summary – SDP vs RDP

Platelet transfusion can be done either by SDP or RDP. SDP uses a single donor while RDP needs whole blood from four to five different donors. SDP is done by a platelet apheresis machine, while in RDP, platelets are prepared by centrifugation. SDP is costly than RDP. But the risk of infections and the risk of alloimmunization is smaller in SDP than in RDP. Moreover, one unit of SDP is equivalent to 5 to 10 units of RDP. However, both methods are effective. Thus, this summarizes the difference between SDP and RDP.

Reference:

1. Blumberg, Neil, et al. “Platelet Transfusions: Trigger, Dose, Benefits, and Risks.” F1000 Medicine Reports, U.S. National Library of Medicine, Available here.
2. “Plateletpheresis.” Wikipedia, Wikimedia Foundation, 28 Jan. 2021, Available here.

Image Courtesy:

1. “Platelets collected by using apheresis” By Whoisjohngalt – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Plasma and platelet donation” By Whoisjohngalt at English Wikipedia (CC BY-SA 3.0) via Commons Wikimedia