The blood is made up of liquid and solids. The liquid part is known as plasma which is made up of water, salt and protein. Over half of the blood is plasma. The solid part of the blood contains red blood cells, white blood cells and platelets.

Plasma Therapy is also known as Convalescent Plasma Therapy (CPT). It can be a possible treatment for COVID-19.

In plasma Therapy, the blood from recovered person is used to treat other sick people as it is rich in antibodies. The convalescent plasma is the liquid part of the blood from the recovered patients of COVID-19. The idea behind the Plasma therapy is that antibodies produced by the patients who have had survived the virus will boost the immune system of those who are critically ill or fighting with the COVID-19.

The first national approach exploited in 1890 by the physiologist's Von Behring and Kitasato to treat diphtheria was blood serum. They found that the serum from an infected animal with diphtheria was effective in preventing the infection caused due to diphtheria. It was stated that initially, it was produced from immunised animals but soon whole blood or serum from recovered donors with a specific humoral immunity were identified as a possible source of specific antibodies of human origin.

Plasma carries dissolved substances from one part to another part in the body. The protein in plasma includes antibodies to assist in the body's defence system against disease or infection. Plasma also contains some traces of other substances like amino acids, organic acids, vitamins, pigments and enzymes.

The process in which the liquid part of the blood or plasma is separated from the blood cells is known as plasmapheresis. The remaining red blood cells and other blood components are then returned to the body of a person along with a little saline solution.

According to Food and Drug Administration, use of convalescent plasma has been studied in outbreaks of other respiratory infections, including the 2003 SARS-CoV-1 epidemic, the 2009-2010 H1N1 influenza virus pandemic, and the 2012 MERS-CoV epidemic.