Serum is separated by centrifugation after clotting without the need of anticoagulant. Serum is a clear yellow fluid without fibrinogen that contains proteins like albumin and globulin, electrolytes, antibodies, antigens, and hormones. On the other hand, plasma is separated by adding anticoagulants (i.e., EDTA, citrate, heparin) before removal of blood cells by centrifugation. It is a yellowish and slightly alkaline fluid with fibrinogen consists of blood clotting agents. It is made up of suspended blood cells with proteins, salts, lipids, and glucose. Plasma plays an important role in managing blood pressure, regulation of body temperature, and transporting excretory metabolites in blood.

Plasma LDH concentration can fluctuate due to platelets leaching across gel barriers in plasma separator gel during storage whereas in serum separator gel, there is only minimal or no leaching of platelet occurs across the gel barrier of the tube upon storage (Bockoven et al., 2022). Hence, in measuring the lactate dehydrogenase concentration, serum is preferable (Bockoven et al., 2022).

- Aryal, S. (2023, June 4). Serum vs. Plasma (17 Major Differences). Microbe Notes. https://microbenotes.com/differences-between-serum-and-plasma/

- Bockoven, C., Benirschke, R. C., & Lee, H. (2022). OUP accepted manuscript. Laboratory Medicine. https://doi.org/10.1093/labmed/lmac026

- Vignoli, A., Tenori, L., Morsiani, C., Turano, P., Capri, M., & Luchinat, C. (2022). Serum or Plasma (and Which Plasma), That Is the Question. Journal of Proteome Research, 21(4), 1061–1072. https://doi.org/10.1021/acs.jproteome.1c00935

• Serum is the clear yellow fluid obtained when blood is allowed to clot freely. It lacks clotting factors while Plasma is a yellowish and slightly alkaline fluid in which blood cells float. It contains blood-clotting agents.
• We use Serum