Blood: What is the difference between plasma and serum?

Human plasma and serum are matrices widely used in clinical and biological studies. However, different collection procedures and the coagulation cascade affect the concentrations of proteins and metabolites in these matrices. The effects on the metabolite concentration profiles have not been fully characterized. Serum is preferred in some tests for cardiac troponins, while plasma is favored in oral glucose tolerance tests for diabetes. As revised by Mannello, the use of an incorrect matrix (e.g. plasma instead of serum) can lead to an incorrect diagnosis 

Both plasma and serum are derived from whole blood which has undergone several biochemical processes after blood collection. Serum is obtained from the blood that has coagulated. The fibrin clots formed during coagulation, together with the blood cells and related coagulation factors, are separated from the serum by centrifugation. During this process, palatelets release proteins,  proinflammatory cytokines and metabolites, sphingosine-1-phosphate into serum. To obtain plasma, an anticoagulant such as EDTA or heparin is added before removing blood cells

Serum

• Definition: serum is the liquid part of the blood after clotting

• Composition: serum is the fluid of blood water without the factors of coagulation

• Volume: the volume of serum is lower than in plasma

• Isolation: the whey is acquired by the spinning process after coagulation

• Isolation procedure: the serum is more difficult and slower to separate

• Use of anticoagulants:  for separation procedure, serum does not require anticoagulants

• Composition: the serum contains proteins, electrolytes, antibodies, antigens and hormones

• Composition (antibodies): the serum contains antibodies and cross-reacts with the receptor antigen

• Composition: whey contains proteins such as albumin and globulins

• Fibrinogen: absent

• Composition (water): the serum contains 90% of water

• Storage: whey can be stored at 2-6 degrees Celsius for several days

• Density: the serum has a density of about 1,024 g / ml

• Arrangement: cells generally unite by clot formation

• Uses: 

• Serum is the most preferred part of the blood used to control blood groups
• Serum is an important source of electrolytes and animal serums are used as anti-poison, antitoxins and vaccines
• Serum is used for various diagnostic tests in the blood, that are used to define the levels of hCG, cholesterol, proteins, sugar, etc.

Plasma

• Definition: Plasma is a clear, yellowish liquid part of the blood

• Composition Plasma is the blood fluid that consists of blood clotting agents

• Volume: plasma is a light yellow liquid which represents 55% of the total blood volume

• Isolation: plasma is acquired by the rotation process before coagulation

• Isolation Procedure: Plasma is easier and less slow to separate than serum

• Use of anticoagulants: serum does not require anticoagulants for separation procedure

• Composition: plasma is considered the blood medium in which red blood cells (red blood cells), white blood cells (white blood cells) and other blood components are suspended

• Composition (antibodies): the plasma does not contain antibodies and does not react with the receptor antigen

• Composition: the plasma contains coagulation factors and water

• Fibrinogen: present

• Composition (water): the plasma contains 92-95% of water

• Storage: Frozen plasma can be stored within a period not exceeding one year

• Density: the plasma has a density of about 1025 kg / m3, or 1.025 g / ml

• Arrangement: cells are not attached to each other and suspended in plasma

• Uses:

• Plasma is used by patients who lack blood cells
• Plasma contains proteins that help in the transport of material such as glucose and other dissolved nutrients through the blood
• Plasma: contribute to maintain blood pressure and regulate body temperature