What is a Serum in Blood?

Serum is a byproduct of blood clotting, in which the plasma protein fibrinogen is converted to fibrin and left behind in the clot. Antiserum - that is prepared from the blood of humans or animals that have been exposed to a disease and have developed specific antibodies, can be used to protect the persons against disease that they have been exposed to.

Study of Serum

Blood is a fluid connective tissue that travels throughout the body by transporting necessary oxygen, nutrients, and metabolic wastes. Also, it is involved in the regulation of the temperature and pH levels of the body by interacting with acids and bases.


Primarily, blood is composed of WBC (white blood cells), RBC (red blood cells), serum, and plasma. Serum and plasma are the primary components of blood and they are routinely used in blood group test experiments for determining the blood group of the patients.


The study of serum is called serology. Serum is used in many diagnostic tests and blood typing as well. Measuring the concentration of different molecules may be useful for several applications, such as determining the therapeutic index of a drug candidate in the clinical trial.


To obtain the serum, a blood sample is allowed to clot (which is called coagulation). Then, the sample is centrifuged to remove the blood cells and clot, and the resulting liquid supernatant is called the serum.

Clinical and Laboratory Uses

Serum from convalescent patients successfully recovering (or having already recovered) from an infectious disease can be used as a biopharmaceutical in the care of other people with the same disease because the antibodies formed by successful recovery are pathogen's potent fighters. Such convalescent serum (which is antiserum) is a form of immunotherapy.


Also, serum is used in protein electrophoresis, because of the lack of fibrinogen that can cause false results.


Fetal bovine serum (FBS) is very rich in growth factors and is frequently added to the growth media used for eukaryotic cell culture. The embryonic stem cells were originally maintained with a cytokine leukaemia inhibitory and an FBS combination factor, but concerns about batch-to-batch differences in FBS led to the production of serum substitutes.

Key Terms

  • Electrolyte: Any of different ions (such as chloride or sodium) that regulate the electric charge on the cells and flow of the water across their membranes

  • Interstitial fluid: In multicellular species, interstitial fluid is a solution contained in tissue spaces that inundates and moistens the cells.

  • Viscosity: It's a measurement of the force per unit area resisting uniform flow in a fluid.

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The above figure shows the blood sample after the centrifugation: The liquid components of the blood, known as plasma (the yellow section) may be separated from the erythrocytes (the red section) and platelets (the white section) by using spinning or centrifuging the blood.

Purification Strategies

Plasma and blood serum meaning are some of the largest sources of biomarkers, whether for therapeutics or diagnostics. Its huge dynamic range, further complicated by the presence of salts, lipids, and the post-translational modifications, and multiple mechanisms of degradation as well, presents the challenges in analytical reproducibility, resolution, sensitivity, and potential efficacy.


For analysis of the biomarkers in blood serum samples, it is possible to perform a pre-separation by a free-flow electrophoresis, which usually consists of a depletion of the serum albumin protein. This particular method enables a greater penetration of the proteome via separation of a variety of chargeable or charged analytes, ranging from small molecules to the cells.

Usage Note

As several other mass nouns, the term serum may be pluralized when used in certain senses. Physicians often use the term sera to refer to multiple serum specimens from multiple individuals (each with its own population of antibodies) (Latin plural, as opposed to as serums).

Enzymes That Test for in the Blood Serum

Usually, enzymes which enter the bloodstream signify something bad, whether it’s myocardial infarction, congenital heart disorders, cancer, and more. The below listed ones are some we'd find and what they exactly mean:

  • Alanine Aminotransferase (ALT; also known as SGPT)

  • Aspartate Aminotransferase (AST; also known as SGOT)

  • A liver enzyme. Can increase when using the cholesterol-lowering medications

A liver enzyme, which is released into the bloodstream following injury or even death of cells. Increased AST is seen with myocardial infarction (MI), liver diseases, and a few medications. Can increase when using cholesterol-lowering medications.

Creatinine (Cr)

Creatinine becomes elevated with kidney disease, illness, muscle injury and a few medications.

Lactate Dehydrogenase (LDH)

LDH is given as an enzyme released in the blood with cell injuries. Often, it is used as a late marker to detect heart attacks. Kidney and liver disease, megaloblastic and pernicious anemias, progressive muscular dystrophy, malignancy, and pulmonary emboli all cause an increase.

Myoglobin (Mb)

Myoglobin is given as a protein found in certain muscle types. Elevated myoglobin can indicate inflammation or muscle injury.

Troponin T (cTNT)

Troponin T is given as a protein found in the blood and it is related to the heart muscle contraction. Troponin T is valuable to detect heart muscle damage and risk.

FAQs (Frequently Asked Questions)

1. What is Human Serum Albumin?

Answer: Human serum albumin is the most abundant protein in human blood plasma, and is synthesized in the liver. Albumin that constitutes around one-half of the blood serum protein, transports fatty acids and hormones, buffers pH, and maintains the osmotic pressures. Immunoglobulin, which is a protein antibody formed in the mucosal lining, plays an essential role in antibody mediated immunity.

2. Explain About Serum.

Answer: Serum contains the plasma portion of blood that lacks coagulation factors, similar to interstitial fluid, and relies on the proper composition of main ions acting as electrolytes for nerve and muscle function.

3. Give the Components of Serum?

Answer: Proteins in serum help preserve osmotic and pH balance while providing viscosity to the blood; antibodies, or specific proteins, help maintain osmotic and pH balance while providing viscosity to the blood, which are essential for defense against bacteria and viruses; lipids, including cholesterol that are transported in the serum; and different other substances including hormones, nutrients, metabolic waste, and the external substances, such as viruses, drugs, and bacteria.

4. What is a Creatine Kinase (CK)?

Answer: A muscle enzyme, which is found in the muscles and heart. Increased CK-MB can be seen with heart muscle damage. An increased CK-MM can be noted with skeletal muscle injury. Weight lifting, strenuous exercise, surgical procedures, high doses of aspirin, and the other medications may elevate CK. Can increase when using cholesterol-lowering medications.