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. 2021 Jul 8;8:682134. doi: 10.3389/fmolb.2021.682134

TABLE 2.

Comparison of Serum Vs. Plasma. The table shows the mean difference, standard error of the mean (SEM), CV%, p-value, and effect size difference of metabolite concentrations (µM) in serum (reference) Vs. each respective plasma type.

Class Metabolite Serum vs. ACD Serum vs. citrate Serum vs. EDTA Serum vs. fluoride Serum vs. heparin
Mean diff SEM %CV p-value a Effect size b Mean diff SEM %CV p-value a Effect size b Mean diff SEM %CV p-value a Effect size b Mean diff SEM %CV p-value a Effect size b Mean diff SEM %CV p-value a Effect size b
Amino Acids and their metabolites 2-Aminobutyrate 2.1 0.6 87.1 0.624 0.22 1.7 0.6 100.7 0.687 0.18 0.5 0.4 241.3 0.935 0.06 −0.3 3.9 −3,356.8 0.959 −0.04 0.2 0.6 980.6 0.935 0.06
2-Hydroxybutyrate 11.0 1.3 32.7 0.027 1.52 6.4 0.6 27.9 0.126 0.80 2.6 0.3 36.8 0.781 0.33 0.4 2.2 1,527.1 0.959 0.05 1.8 0.8 121.0 0.858 0.20
2-Hydroxyisovalerate 2.1 0.5 66.1 0.167 0.91 1.0 0.3 93.7 0.332 0.36 0.5 0.2 90.1 0.781 0.17 0.3 1.6 1,460.7 0.632 0.11 0.5 0.1 86.5 0.858 0.16
2-Oxoisocaproate 1.7 0.3 45.2 0.031 1.51 0.8 0.2 50.4 0.373 0.63 0.5 0.1 50.2 0.831 0.39 0.2 0.8 1,255.0 0.784 0.14 0.2 0.1 136.1 0.887 0.14
3-Hydroxyisobutyrate 3.8 0.4 26.7 0.027 1.82 2.4 0.2 22.1 0.086 1.09 0.5 0.3 178.9 0.879 0.22 1.4 0.7 129.2 0.513 0.66 0.5 0.2 106.9 0.858 0.24
3-Methyl-2-oxobutanoate 5.1 0.6 33.6 0.019 1.83 2.4 0.3 35.7 0.186 0.74 1.2 0.3 65.3 0.781 0.35 0.6 2.1 953.6 0.887 0.19 0.4 0.4 251.0 0.858 0.13
Alanine 96.2 6.8 19.9 0.023 1.78 83.9 4.6 15.5 0.039 1.47 39.8 4.3 30.9 0.696 0.65 79.6 29.2 103.7 0.141 1.38 39.8 4.6 32.8 0.858 0.63
Arginine 18.2 2.6 39.6 0.018 1.96 17.7 2.2 34.6 0.021 1.75 13.9 3.8 77.6 0.148 1.65 13.8 6.3 129.7 0.141 1.33 13.2 3.5 75.7 0.341 1.12
Asparagine 14.1 1.3 27.0 0.018 1.81 10.7 1.8 47.0 0.047 1.39 3.9 0.9 65.9 0.781 0.46 10.5 3.6 95.8 0.191 1.23 4.1 1.4 96.8 0.858 0.47
Betaine 6.4 1.5 64.3 0.370 0.37 8.9 1.3 41.6 0.332 0.55 1.6 0.6 117.2 0.879 0.09 8.6 6.6 219.2 0.434 0.53 1.9 0.9 134.7 0.887 0.11
Glutamate 3.3 2.6 219.7 0.562 0.41 20.7 2.3 31.9 0.005 2.83 5.8 3.2 156.3 0.781 0.67 10.2 4.6 127.0 0.141 1.13 14.1 1.5 30.8 0.174 1.49
Glutamine 101.1 9.9 27.8 0.027 1.66 80.7 5.9 20.7 0.047 1.37 34.4 9.3 76.8 0.669 0.55 79.9 31.7 112.1 0.141 1.30 24.1 9.6 112.0 0.858 0.36
Glycine 66.9 5.7 23.9 0.031 1.35 58.6 3.4 16.6 0.047 1.13 8.4 1.9 63.3 0.869 0.15 50.3 34.2 192.1 0.141 0.97 26.4 3.4 36.8 0.812 0.49
Histidine 12.6 2.2 49.1 0.031 1.59 6.9 2.1 85.7 0.263 0.86 −0.9 0.9 -284.3 0.879 −0.12 14.4 5.8 112.8 0.141 1.55 5.0 1.9 108.3 0.858 0.52
Isoleucine 12.6 1.1 25.1 0.096 1.18 8.9 1.1 34.6 0.223 0.82 3.1 0.6 55.3 0.869 0.28 3.3 7.5 652.2 0.631 0.29 3.6 0.9 73.0 0.858 0.31
Leucine 21.7 1.9 24.4 0.050 1.28 20.4 2.3 31.2 0.076 1.20 8.8 1.0 30.5 0.781 0.47 9.3 12.1 368.1 0.498 0.49 5.4 1.9 99.1 0.858 0.29
Lysine 29.3 2.5 24.1 0.096 1.09 24.1 2.3 27.0 0.186 0.88 5.1 2.1 115.2 0.879 0.19 21.8 12.4 160.4 0.390 0.78 9.7 1.9 54.9 0.858 0.34
Methionine 7.6 0.5 20.0 0.007 2.82 4.9 0.4 23.9 0.027 1.67 1.5 0.7 126.1 0.869 0.46 1.7 1.9 319.1 0.365 0.52 1.3 0.7 147.1 0.858 0.39
N,N-Dimethylglycine 0.6 0.1 37.8 0.096 1.01 0.4 0.1 44.0 0.332 0.67 0.2 0.1 152.0 0.879 0.24 0.3 0.4 386.3 0.579 0.44 0.1 0.0 87.4 0.858 0.15
Ornithine 28.0 2.9 29.5 0.007 2.42 24.5 2.8 32.3 0.012 1.98 12.8 1.7 37.6 0.461 0.91 15.8 8.4 150.9 0.166 1.18 13.7 1.9 40.0 0.692 0.93
Phenylalanine 12.1 0.4 10.1 0.018 2.02 10.3 0.7 20.4 0.031 1.76 6.8 0.4 18.3 0.416 1.06 7.9 3.7 132.7 0.166 1.18 7.8 1.1 38.6 0.174 1.17
Proline 41.5 4.5 30.6 0.142 1.01 33.9 5.8 48.3 0.126 0.82 11.4 3.1 77.5 0.869 0.25 23.0 27.5 337.8 0.390 0.53 13.0 2.9 62.9 0.858 0.29
Serine 36.1 3.5 27.2 0.040 1.54 37.2 3.0 22.6 0.031 1.58 19.5 3.3 47.6 0.593 0.77 32.0 14.2 125.4 0.166 1.27 20.4 2.2 29.9 0.812 0.78
Taurine 13.2 4.6 97.9 0.083 0.94 91.0 5.5 17.1 0.002 6.07 87.4 5.7 18.3 0.004 6.08 80.6 4.5 15.9 0.004 5.14 79.2 4.9 17.5 0.008 6.93
Threonine 24.7 2.7 31.1 0.031 1.02 20.4 2.8 38.5 0.076 0.85 4.1 2.9 201.2 0.928 0.15 13.4 10.2 215.6 0.291 0.51 6.9 2.0 80.6 0.858 0.26
Tryptophan −0.6 0.3 −164.7 0.672 −0.48 1.4 0.4 87.1 0.086 1.16 0.7 0.4 168.9 0.696 0.74 1.2 0.6 141.9 0.166 1.22 0.8 0.4 166.7 0.812 0.74
Tyrosine 11.6 0.7 17.6 0.040 1.37 9.4 0.9 27.8 0.061 1.10 3.3 0.5 44.6 0.869 0.36 5.2 6.0 327.1 0.390 0.57 4.2 1.0 65.6 0.812 0.44
Valine 51.4 3.7 20.1 0.018 1.64 38.6 3.1 22.3 0.086 1.18 12.8 2.5 55.3 0.869 0.36 16.6 20.4 348.6 0.513 0.46 15.4 3.6 66.0 0.858 0.42
Ketone bodies 3-Hydroxybutyrate 16.0 5.0 88.3 0.329 0.36 14.1 5.2 103.1 0.332 0.30 −8.9 8.5 −269.0 0.935 −0.03 −9.0 13.8 −431.7 0.959 −0.05 2.4 4.1 476.1 0.979 0.01
Acetoacetate 2.3 1.8 224.6 0.672 0.24 −28.1 0.7 −7.3 0.027 −1.78 8.2 5.9 −202.2 0.869 −0.22 −8.7 6.7 −217.6 0.700 −0.25 −2.3 0.8 −102.4 0.858 −0.15
Acetone −13.4 1.4 −29.2 0.115 −1.24 −94.5 5.9 −17.6 0.002 −3.71 −0.2 0.6 −997.6 0.935 −0.03 1.8 3.9 598.3 0.631 0.14 1.3 0.6 126.3 0.858 0.08
Lipid metabolism Carnitine 0.7 1.0 426.3 1.000 0.13 6.2 0.9 41.1 0.031 1.57 −0.3 1.5 −1,298.8 0.999 −0.04 4.7 2.3 136.6 0.166 1.09 0.9 0.6 209.4 0.858 0.19
O-Acetylcarnitine 2.4 0.1 17.4 0.027 1.63 2.0 0.3 34.5 0.086 1.35 0.2 0.5 650.1 0.879 0.17 0.8 0.7 243.8 0.513 0.58 0.2 0.5 573.5 0.979 0.15
Others Choline 1.5 0.2 32.1 0.050 1.20 1.9 0.2 28.9 0.021 1.60 −1.5 2.0 −389.6 0.935 −0.26 0.5 0.9 511.1 0.632 0.38 0.8 0.1 43.2 0.812 0.61
Dimethyl sulfone 1.7 0.3 42.7 0.167 0.87 1.2 0.1 33.2 0.332 0.60 0.0 0.3 3,146.6 0.879 −0.07 0.3 1.0 825.3 0.819 0.14 0.4 0.2 132.6 0.858 0.18
Methanol −40.2 2.1 −14.8 0.010 −2.06 −1.4 1.1 −220.0 0.751 −0.20 0.1 0.7 3,646.4 1.000 −0.06 −0.1 8.2 −18325.4 0.959 −0.07 0.4 1.4 1,147.7 0.887 −0.08
Urea 1374.6 128.3 26.4 0.007 2.33 1,108.5 115.7 29.5 0.021 1.95 527.3 77.5 41.6 0.461 0.79 424.5 387.6 258.2 0.434 0.62 322.8 84.3 73.9 0.838 0.48
Polyamines and creatine Creatine 7.2 1.3 51.9 0.373 0.43 7.8 1.4 50.2 0.425 0.47 0.4 0.8 551.1 0.928 0.05 4.6 7.9 484.0 0.632 0.28 1.9 0.8 118.8 0.858 0.10
Creatinine 13.8 1.4 27.7 0.115 1.13 10.6 1.0 27.2 0.126 0.83 2.6 0.8 87.5 0.869 0.20 7.0 5.1 206.5 0.365 0.51 2.4 1.4 161.6 0.858 0.18
Pyruvate metabolism Lactate 1285.8 90.8 20.0 0.002 2.91 1129.1 55.3 13.8 0.008 2.60 535.6 76.4 40.3 0.593 1.07 976.5 266.9 77.3 0.087 1.75 623.1 57.5 26.1 0.499 1.25
Pyruvate −17.4 8.0 −130.9 0.332 −0.82 −8.5 4.3 −143.8 0.549 −0.44 −38.2 5.4 −39.6 0.148 −1.44 66.2 10.0 42.7 0.004 7.60 −4.5 3.4 −210.7 0.935 −0.16
Short-chain fatty acids (SCFAs) Acetate −1.0 2.5 −718.5 0.815 −0.12 −18.8 2.0 −29.5 0.031 −1.66 −22.5 2.9 −36.6 0.078 −1.85 −13.6 5.3 −110.7 0.343 −1.15 −5.1 1.8 −100.1 0.858 −0.40
Butyrate 1.4 0.2 35.5 0.031 1.85 0.9 0.2 70.0 0.126 1.07 0.4 0.1 97.2 0.781 0.45 −0.5 0.5 −290.0 0.632 −0.45 0.2 0.3 314.2 0.858 0.29
Formate −123.1 2.0 −4.5 0.002 −20.91 −24.7 0.6 −6.5 0.002 −9.27 −171.4 2.6 −4.3 0.004 −23.60 −1.3 0.7 −144.7 0.506 −0.65 −1.2 0.5 −120.6 0.858 −0.64
Sugars Glucose −18253.0 338.5 −5.2 0.002 −27.52 377.6 48.4 36.2 0.039 1.22 −200.2 74.0 −104.6 0.869 -0.47 6.7 150.7 6,328.0 0.955 0.04 6.9 69.9 2,858.2 1.000 0.02
Mannose 5.3 1.3 68.5 0.293 0.76 1.4 0.8 154.8 0.878 0.20 −1.7 1.4 −243.3 0.879 −0.26 −1.8 3.4 −547.7 0.768 −0.18 −1.9 0.9 −137.4 0.858 −0.25
Myo inositol 7.2 0.7 26.7 0.003 2.75 7.3 1.0 40.1 0.002 2.97 2.6 1.2 127.3 0.461 0.98 6.7 1.1 48.1 0.010 2.33 1.7 0.5 88.0 0.838 0.62
Tricarboxylic acid (TCA) cycle 2-Oxoglutarate 2.4 0.7 80.0 0.096 1.16 1.2 0.7 156.7 0.373 0.52 −0.7 0.7 −260.8 0.869 −0.35 2.6 1.5 164.6 0.191 1.07 0.6 0.3 134.1 0.858 0.24
Citrate −32701.4 1,031.2 −8.9 0.002 −25.64 −20904.7 566.8 −7.7 0.002 −23.90 −7.7 4.4 −160.0 0.831 −0.26 −14.9 16.8 -320.5 0.365 −0.44 19.5 3.7 53.4 0.812 0.64
Succinate −2.7 0.5 −50.7 0.065 −1.35 −0.1 0.2 −587.7 0.851 −0.05 0.4 0.3 208.1 1.000 0.12 1.3 1.0 221.8 0.632 0.55 0.8 0.2 87.9 0.858 0.30
a

Pairwise comparison between serum (Reference) compared to each plasma type was performed using the Mann-Whitney U test.

b

Effect size (δ) between serum and each plasma tube are presented: |δ| < 0.33 corresponds to small, |δ| < 0.474 corresponds to medium, and |δ| > 0.475 corresponds to large effect size in metabolite concentration differences.