title: Differences between human plasma and serum metabolite profiles.
abstract: BACKGROUND
  Human plasma and serum are widely used matrices in clinical and biological studies. However, different collecting procedures and the coagulation cascade influence concentrations of both proteins and metabolites in these matrices. The effects on metabolite concentration profiles have not been fully characterized.
  
  
  RESULTS
  We analyzed the concentrations of 163 metabolites in plasma and serum samples collected simultaneously from 377 fasting individuals. To ensure data quality, 41 metabolites with low measurement stability were excluded from further analysis. In addition, plasma and corresponding serum samples from 83 individuals were re-measured in the same plates and mean correlation coefficients (r) of all metabolites between the duplicates were 0.83 and 0.80 in plasma and serum, respectively, indicating significantly better stability of plasma compared to serum (p = 0.01). Metabolite profiles from plasma and serum were clearly distinct with 104 metabolites showing significantly higher concentrations in serum. In particular, 9 metabolites showed relative concentration differences larger than 20%. Despite differences in absolute concentration between the two matrices, for most metabolites the overall correlation was high (mean r = 0.81±0.10), which reflects a proportional change in concentration. Furthermore, when two groups of individuals with different phenotypes were compared with each other using both matrices, more metabolites with significantly different concentrations could be identified in serum than in plasma. For example, when 51 type 2 diabetes (T2D) patients were compared with 326 non-T2D individuals, 15 more significantly different metabolites were found in serum, in addition to the 25 common to both matrices.
  
  
  CONCLUSIONS
  Our study shows that reproducibility was good in both plasma and serum, and better in plasma. Furthermore, as long as the same blood preparation procedure is used, either matrix should generate similar results in clinical and biological studies. The higher metabolite concentrations in serum, however, make it possible to provide more sensitive results in biomarker detection.
authors.affiliation: Research Unit of Molecular Epidemiology, Helmholtz Zentrum München, Neuherberg, Germany.
authors.forename: Zhonghao
authors.initials: Z
authors.lastname: Yu
authors.forename: Gabi
authors.initials: G
authors.lastname: Kastenmüller
authors.forename: Ying
authors.initials: Y
authors.lastname: He
authors.forename: Petra
authors.initials: P
authors.lastname: Belcredi
authors.forename: Gabriele
authors.initials: G
authors.lastname: Möller
authors.forename: Cornelia
authors.initials: C
authors.lastname: Prehn
authors.forename: Joaquim
authors.initials: J
authors.lastname: Mendes
authors.forename: Simone
authors.initials: S
authors.lastname: Wahl
authors.forename: Werner
authors.initials: W
authors.lastname: Roemisch-Margl
authors.forename: Uta
authors.initials: U
authors.lastname: Ceglarek
authors.forename: Alexey
authors.initials: A
authors.lastname: Polonikov
authors.forename: Norbert
authors.initials: N
authors.lastname: Dahmen
authors.forename: Holger
authors.initials: H
authors.lastname: Prokisch
authors.forename: Lu
authors.initials: L
authors.lastname: Xie
authors.forename: Yixue
authors.initials: Y
authors.lastname: Li
authors.forename: H-Erich
authors.initials: HE
authors.lastname: Wichmann
authors.forename: Annette
authors.initials: A
authors.lastname: Peters
authors.forename: Florian
authors.initials: F
authors.lastname: Kronenberg
authors.forename: Karsten
authors.initials: K
authors.lastname: Suhre
authors.forename: Jerzy
authors.initials: J
authors.lastname: Adamski
authors.forename: Thomas
authors.initials: T
authors.lastname: Illig
authors.forename: Rui
authors.initials: R
authors.lastname: Wang-Sattler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D055442:Metabolome; D008875:Middle Aged; D010949:Plasma / Q000378:metabolism*; D015203:Reproducibility of Results; D044967:Serum / Q000378:metabolism*