Serum is not Plasma is not Whole Blood
Serum has been used as a parenteral drug (1,2) since early in the last century. A recent article (3) on the use of umbilical cord serum as a topical treatment for ocular burns caught my attention as did as a article on difference between serum and plasma concentration of monocyte chemotactic protein -1 (MCP-1) (4). Earlier studies from another laboratory has shown that growth factor concentrations are higher in umbilical cord serum than those found in peripheral serum (5). Ang and coworkers (6) used umbilical cord serum in the media for the growth of conjunctival and limbal epithelial cells observing that growth factor concentrations were higher in umbilical cord seum than either fetal bovine serum or normal adult human serum. In a related study, Murphy and coworkers (7) showed that platelet-rich plasma derived from umbilical cord blood was more effective in supporting mesenchymal stem cell growth than adult platelet-rich plasma or a combination of recombinant growth factors. It is noted that umbilical cord blood is a source of hematopoietic stem cells which can be used for transplantation (8).
The other paper (4) on MCP-1 concentrations in plasma and serum is a bit more complex. The observation is that the Asp42Gly polymorphism in Duffy antigen receptor for chemokines (Darc) influenced the concentration of MCP-1 in serum but not plasma. This is consistent with an earlier larger study (9) showing the increased concentration in serum is indeed due to binding of MCP-1 to erythrocytes. MCP-1 is synthesized by a variety of cells (10) and a chemokine receptor on erythrocytes was identified some time ago (11). The effect of Darc polymorphism may have a confounding effect on the use of MCP-1 as a biomarker (12). Some of the above studies used EDTA as an anticoagulant; one study(13) suggests that EDTA plasma is unsuitable for determination of platelet-derived angiogenic cytokines. Another study showed that heparin and EDTA had a different effect on cytokine mRNA levels in cultured porcine blood cells (14). This is just a small collection of the various studies which could be cited to illustrate the importance of sample definition. I and colleagues have previous considered this issue (15,16).
Unlike a decade ago, issues of plasma and serum and anticoagulants are being considered by investigators pursuing biomarkers (17-23). It is critical to consider the importance of sample preparation and, in the case of plasma, the choice of anticoagulant. In addition, the selection of sample storage devices, processing conditions, and conditions of storage is critical for either plasma or serum.
1. Flexner, S. and Amoss, R.L., The passage of neutralizing substance from the blood into the cerebrospinal fluid in actively immunized monkeys, J.Exp.Med. 28, 11-17, 1981
2. Struma, M.M., Wagner, J.A., and Monaghan, J.F., The intravenous use of serum and plasma, fresh and preserved, Ann.Surg. 111, 623-628, 1940.
3. Sharma, N., Goel, M., Velpandian, T., et al., Evaluation of umbilical cord serum therapy in acute ocular chemical burns, Investigative Ophthalmol.Vis.Sci. 5, 1087-1092, 2011.
4. Aragones, G., Ercilla, A., Barreda, M., et al., Human duffy blood group alloantigen system influences the measurement of monocyte chemotactic protein-1 (MCP-1) in serum but not in plasma, Clin.Lab. 58, 185-288, 2012.
5. Yoon, K.-C., Im, S.-K., Park, Y.-G., et al., Application of umbilical cord serum eye drops for the treatment of dry eye syndrome, Cornea 25, 268-272, 2006.
6. Ang, L.P., Do, T.P., Thein, Z.M., et al., Ex vivo expansion of conjuntival and limbal epithelial cells using cord blood serum-supplemented culture media, Invest.Ophthalmol.Vis.Sci. 52, 6138-6147, 2011.
7. Murphy, M.B., Blashki, D., Buchanan, R.M.,. et al., Adult and umbilical cord blood-derived platelet rich plasma for mesengial stem cell proliferation, chemotaxis, and cryopreservation, Biomaterials, in press, 2012.
8. Rao, M., Ahrlund-Richter, L., and Kaufman, D.S., Cord blood banking, transplantation and induced pluripotent stem cell: success and opportunities, Stem Cells 30, 55-60, 2012.
9. Schabel, R.G., Baumert, J., Barbalic, M., et al., Duffy antigen receptor for chemokines (Darc) polymorphism regulated circulating concentrations of monocyte chemotactic protein-1 and other inflammatory mediators, Blood 115, 5289-5299, 2010.
10. Clark-Lewis, I., Kim, K.-S., Rajarathnam, K., et al., Structure-activity relationships of chemokines, J.Leuk.Biol. 57, 703-711, 1995.
11. Horuk, R., Colby, T.J., Darbonne, W.C., et al., The human erythrocyte inflammatory peptide (chemokine) receptor. Biochemical characterization, solubilization, the development of a binding assay for the soluble receptor, Biochemistry 32, 5735-5738, 1993.
12. Marsillach, J., Bertran, N., Camps, J., et al., The role of circulating monocyte chemoattractant protein-1 as a marker of hepatic inflammation in patients with chronic liver disease, Clin.Biochem. 38, 1138-1140, 2005.
13. Zimmermann, R., Ringwald, J., and Eckstein, R., EDTA plasma is unsuitable for in vivo determinations of platelet-derived angiogenic cytokines, J.Immunol.Methods 347, 91-92, 2009.
14, Duvigneau, J.C., Sipos, W., Hartl, R.T., et al., Heparin and EDTA as anticoagulant differentially affect cytokine mRNA level of cultured porcine blood cells, J.Immunol.Methods 324, 38-47, 2007.
15. Sapan, C.V. and Lundblad, R.L., Considerations Regarding the Use of Blood Samples in the Proteomic Identification of Biomarkers for Cancer Diagnosis, Cancer Genomics and Proteomics, 33, 227-231, 2006.
16. Burgess, C. and Lundblad, R.L., Plasma or serum in proteomic analysis, Clinical Laboratory International, 31(1), 10-11, 2007.
17. Tammen, H., Schulte, I., Hess, R., et al., Peptidomic analysis of human blood specimens: Comparison between plasma specimens and serum by differential peptide display, Proteomics 5, 3414-3422, 2005.
18. West-Nielsen, M., Hogdall, E.V., Marchiori, E., et al., Sample handing for mass spectrometric proteomic investigations of human sera, Anal.Chem. 77, 5114-5123, 2005.
19. Luque-Garcia, J.L. and Neubert, T.A., Sample preparation for serum/plasma profiling and biomarker identification by mass spectrometry, J.Chromatog.A. 1153, 259-276, 2007.
20. Daves, M., Trevisan, D., and Cemin, R., Different collection tubes in cardiac biomarkers detection, J.Clin.Lab.Anal. 22, 391-394, 2008.
21. Tuck, M.K., Chan, D.W., Chia, D., et al., Standard operating procedures for serum and plasma collection: Early detection research network consensus statement Standard Operating Procedure Integration Working Group, J.Proteome Res. 8, 113-117, 2009.
22. Insenser, M., Martinez-Gomez, M.A., Nieto, R.M., et al., Impact of the storage temperature on human plasma proteomic analysis: Implications for the use of human plasma collections in research, Proteomics Clinical Applications 4, 739-744, 2010.
23. Surinova, S., Schless, R., Hüttenhain, R., et al., On the development of plasma protein biomarkers, J.Proteome Res. 10, 5-16, 2011.
Gerlach RF, Demacq C, Jung K, Tanus-Santos JE. Rapid separation of serum does
not avoid artificially higher matrix metalloproteinase (MMP)-9 levels in serum
versus plasma. Clin Biochem. 2007 Jan;40(1-2):119-23. Epub 2006 Oct 19. PubMed