The Value of Serum in Health Research

You may have heard that human serum is one of the most important tools in today’s laboratory, but let’s look at why.

What is human serum?
Human serum is a clear bodily fluid that is obtained from whole blood. It is the substance that remains when a blood sample is centrifuged to separate out the red and white blood cells, platelets, and clotting factors. (Another way to think of serum is as the clear liquid that remains after blood has fully clotted around a fresh scrape.) Serum contains antibodies, hormones, enzymes, vitamins, sugars, fats, and proteins. Plasma is similar but different: it is serum plus clotting factors. Serum is preferred over plasma in many clinical laboratory applications because the clotting factors can cause interference in sensitive tests.

What is human serum used for?
Human serum is commonly used in research concerning immunity and in developing therapeutic agents and supplements to boost natural immunity. It is used to grow cells in culture media, as an alternative to serum derived from animals. Serum is an essential component for growing immune cells outside of the human body, which makes it a key part of biomedical research.1

What can human serum reveal?
Serum contains proteomic and metabolomic markers that are useful for a variety of applications.

  • Proteomic markers. Human serum contains an abundance of proteins, and proteins are an important indicator of an individual’s health or disease status. The presence or lack of certain proteins may signal disease onset and/or lead to an early diagnosis.2 If an individual has been infected with a particular pathogenic agent, or has a particular disease such as certain cancers, serological tests can help detect it. This is because serum contains things such as immunoglobulins (protein molecules that have antibody activity), rheumatoid factor (used to diagnose arthritis), and human leukocyte antigens (used to test for paternity; for compatibility in organ, tissue, and bone marrow transplantation; and also for human leukocyte antigen-linked disorders such as auto-immune conditions).3
  • Metabolomic markers. The metabolome is the collection of intermediate and waste products given off by biological reactions in a sample. It is useful for studying the health of an organism. Although metabolomic data shows up in urine, saliva, and soft tissues, human serum is particularly useful because it reflects the current state of an individual.4

What else is human serum used for?
Human serum is preferred for certain applications such as DNA research, cell cultures, and cancer therapy studies where animal serum could result in findings that can’t be applied to people.5 Studying serum from individuals who live with certain diseases is one way to uncover novel targets for the development of new drugs. Further, human cells often need human serum to grow properly, so any research involving human cell lines will often require serum from a human source.6

Serum is also used for epidemiological surveillance studies to identify people within a population who have protective immunity to specific diseases, or to measure past exposures.7 Comparing serological profiles from the same population over time can provide insights to changes in the prevalence of diseases and changes in health or nutritional status. For example, since 1985 the US Department of Defense has curated a serum depository for health protection goals. Samples are collected before and after military deployments.8

Human serum is also useful in therapeutic applications. When people recover from an infectious illness, their serum contains disease-fighting antibodies specific to what infected them. This can be collected and transferred to other individuals who are ill with the same disease, to boost their immune system’s response. While it’s playing catchup compared to vaccination, serum therapy — also called convalescent plasma therapy — can help save lives while a vaccine is being developed or distributed.9

There is no synthetic version of human serum; it contains things that simply can’t be manufactured. Which is why researchers rely on the life science services industry to ethically and properly collect blood serum for use in research.

References

1. Pitclik H. Serum for research: What is serum donation? The BloodLine. 12/30/2020. Available at https://blog.bloodworksnw.org/serum-for-research-what-is-serum-donation. Accessed 9/8/2021.
2. Zhang AH, Sun H, Yan GL, Han Y, Wang XJ. Serum proteomics in biomedical research: a systematic review. Appl Biochem Biotechnol. 2013;170(4):774-786. doi:10.1007/s12010-013-0238-7
3. Johns Hopkins Medicine. Immunology and Serology. Available at https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/immunology-and-serology. Accessed on 9/8/2021.
4. James EL, Parkinson EK. Serum metabolomics in animal models and human disease. Curr Opin Clin Nutr Metab Care. 2015;18(5):478-483. doi:10.1097/MCO.0000000000000200
5. Heger JI, Froehlich K, Pastuschek J, et al. Human serum alters cell culture behavior and improves spheroid formation in comparison to fetal bovine serum. Exp Cell Res. 2018;365(1):57-65. doi:10.1016/j.yexcr.2018.02.017

6. BioChemEd services. Human Serum and its Important Role in Research. 4/15/2019. Available at https://www.biochemed.com/news/human-serum-and-its-important-role-in-research. Accessed 9/8/2021.
7. Arnold BF, Scobie HM, Priest JW, Lammie PJ. Integrated Serologic Surveillance of Population Immunity and Disease Transmission. Emerg Infect Dis. 2018;24(7):1188-1194. doi:10.3201/eid2407.171928
8. Perdue CL, Eick-Cost AA, Rubertone MV. A Brief Description of the Operation of the DoD Serum Repository. Mil Med. 2015;180(10 Suppl):10-12. doi:10.7205/MILMED-D-14-00739
9. Hansen B. The story of serum therapy: How a 19th-century invention could save lives today. Science History Institute. 4/28/2020. Available at https://www.sciencehistory.org/distillations/the-story-of-serum-therapy. Accessed 9/8/2021.