What is an apheresis machine and why is it important?

Blood is made up of four main components: plasma, red blood cells, white blood cells (WBC) and platelets. Blood has many functions including transporting oxygen from the lungs throughout the body, carrying cells that are present in the immune system and preventing blood clots and blood loss from occurring.


Figure 1. | The general composition of blood.


Apheresis machines can be used to split plasma from the blood. Plasma can be used for the treatment of many diseases including COVID-19. Plasma is made up of water, salts, sugars, proteins and fats. In the body, plasma is responsible for transporting nutrients around the body through the blood cells. To test whether a person has COVID-19, one treatment is by observing the amount of WBC in the body. It was found that patients with COVID had a significantly lower number of WBC than those who do not have coronavirus.

 Plasma is useful as some types of WBC can create antibodies which are proteins that fight infections. There are also some types of WBC, called memory T cells, that memorise the types of infections an individual has been exposed to and how it has fought it. This means that if a person is exposed to the same infection, WBCs recognise the foreign material and will quickly destroy it before a person can experience any symptoms. Hence, one of the treatments for COVID in Iran is plasma transfusion. The plasma taken from people who have survived COVID contains memory T cells that have fought the virus. Furthermore, generally, people who recover from viral infections tend to have a low level of platelets. Once again, platelets from plasma transfusion can increase the number of platelets in coronavirus patients and prevent blood clotting. Transferring this plasma to patients who have COVID-19, could potentially help people to fight this virus.


Figure 2. | Importance of plasma.


In Iran, the COVID-19 outbreak has had a significant impact on the country. In the Sayyidul Shuhada Hospital, the number of patients with COVID is large. Currently, there is only one apheresis machine in the hospital and one more is required.


How does an apheresis machine work?

People can donate their plasma for medical use. The blood from a vein in a person’s arm is transferred through an intravenous tube to the apheresis machine. Inside the apheresis machine, there is a centrifuge which is a container that rapidly rotates, causing liquids of different densities to separate. The centrifuge then spins and separates the blood and plasma. The plasma is stored in bags so that the WBC and platelets suspended in the plasma can be used for various treatments. The blood is then transported from the apheresis machine back to the donor’s body via another intravenous tube.


Figure 3. | Simplified diagram of the process of an apheresis machine.



The rise of COVID-19 cases in Iran has greatly affected the country. Hospitals are unable to treat all their patients and thus the Sayyidul Shuhada Hospital requires another apheresis machine. Plasma transfusions are important as WBC and platelets are an important part of treatment for COVID. This is because WBC contains memory cells and platelets prevent blood clots. By using plasma donated by people who have been successful in fighting COVID, patients who are suffering from coronavirus can use memory T cells and other WBC to treat the virus. Hence, an additional apheresis machine for the Sayyidul Shuhada Hospital would be very beneficial for patients in critical stages of COVID-19.