Table 3.
Back-calculated accuracy and precision of standard solutions and plasma sample at three spiking levels.
| Analyte | Standard solutions - % Accuracy ± s (conc µmol L−1) | Spiked plasma samples - % Accuracy ± s (conc µmol L−1) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Intra-day (N = 3) | Inter-day (N = 3) | Intra-day (N = 3) | Inter-day (N = 3) | |||||||||
| Low | Medium | High | Low | Medium | High | Low | Medium | High | Low | Medium | High | |
| Pyruvate | 94 ± 20 (0.8) | 109 ± 1 (25) | 96.8 ± 0.1 (100) | 90 ± 6 (0.8) | 105 ± 4 (25) | 96 ± 3 (100) | 92 ± 10 (20) | 92 ± 4 (40) | 85.0 ± 1.0 (50) | 94 ± 7 (20) | 97 ± 5 (40) | 89 ± 3 (50) |
| Lactate | 115 ± 18 (3.9) | 93 ± 7 (250) | 97 ± 11 (1000) | 114 ± 3 (3.9) | 96 ± 3 (250) | 99 ± 4 (1000) | 69 ± 10 (250) | 96 ± 14 (50)* | 95 ± 5 (100)* | 83 ± 14 (250) | 120 ± 30 (50)* | 100 ± 30 (100)* |
| Acetoacetate | 108 ± 7 (3.1) | 96 ± 4 (25) | 100.9 ± 1.8 (100) | 107.3 ± 0.5 (3.1) | 102 ± 8 (25) | 100.2 ± 1.6 (100) | 70 ± 50 (10) | 72 ± 18 (20) | 69 ± 7 (50) | 90 ± 20 (10) | 68 ± 18 (20) | 71 ± 14 (50) |
| β-hydroxybutyrate | 112.6 ± 1.8 (0.4) | 103 ± 6 (25) | 97.3 ± 3.8 (100) | 103 ± 9 (0.4) | 104 ± 3 (25) | 97.8 ± 0.4 (100) | 65 ± 17 (10) | 69 ± 3 (20) | 63 ± 3 (50) | 77 ± 12 (10) | 80 ± 30 (20) | 74 ± 13 (50) |
| Succinate | 119 ± 12 (0.1) | 100 ± 2 (6.3) | 97.9 ± 0.8 (25) | 118 ± 9 (0.1) | 102 ± 4 (6.3) | 97.2 ± 0.6 (25) | 85 ± 10 (2) | 93 ± 7 (4) | 87.0 ± 0.8 (10) | 99 ± 16 (2) | 110 ± 20 (4) | 95 ± 11 (10) |
| Fumarate | 96 ± 2 (0.1) | 87 ± 2 (6.3) | 105.9 ± 0.9 (25) | 103 ± 6 (0.1) | 95 ± 7 (6.3) | 102 ± 3 (25) | 74 ± 8 (2) | 80 ± 6 (4) | 62.00 ± 0.17 (10) | 80 ± 30 (2) | 100 ± 30 (4) | 80 ± 30 (10) |
| Malate | 94 ± 3 (0.1) | 87 ± 2 (6.3) | 104.5 ± 0.7 (25) | 109 ± 13 (0.1) | 94 ± 7 (6.3) | 103 ± 3 (25) | 82 ± 11 (2) | 87 ± 7 (4) | 97.0 ± 0.5 (10) | 94 ± 17 (2) | 100 ± 30 (4) | 103 ± 17 (10) |
| α-ketoglutarate | 93 ± 16 (0.1) | 105 ± 3 (6.3) | 96.5 ± 1.1 (25) | 100 ± 7 (0.1) | 107.6 ± 1.7 (6.3) | 99 ± 2 (25) | 97 ± 11 (2) | 103 ± 9 (4) | 98.0 ± 0.9 (10) | 111 ± 12 (2) | 111 ± 10 (4) | 114 ± 17 (10) |
Note: Values within brackets indicate the concentration of each metabolite in the standard solution/spiking concentration.
*Measured in 1:10 diluted sample.