Table 2.
Consensus concentrations of the 4 measured ceramides in the 4 NIST reference materials
| Matrix | Ceramide | n (SP) (SOP/OTH) | n (MP) (SOP/OTH) | μmol/L (SP) mean | μmol/L (SP) SEM | μmol/L (MP) mean | μmol/L (MP) SEM | Inter-lab %CV (SP) | Inter-lab %CV (MP) | Intra-lab %CV (MP) |
|---|---|---|---|---|---|---|---|---|---|---|
| SRM | Cer 18:1;O2/16:0 | 33 (21/12) | 35 (21/14) | 0.3507 | 0.0056 | 0.2438 | 0.0057 | 9.2 | 13.8 | 4.2 |
| Cer 18:1;O2/18:0 | 33 (22/11) | 31 (21/10) | 0.0553 | 0.0009 | 0.0835 | 0.0017 | 9.8 | 11.6 | 4.2 | |
| Cer 18:1;O2/24:0 | 35 (20/15) | 35 (20/15) | 2.5670 | 0.0494 | 2.4116 | 0.0413 | 11.4 | 10.1 | 3.7 | |
| Cer 18:1;O2/24:1 | 32 (21/11) | 31 (20/11) | 0.8397 | 0.0221 | 0.8554 | 0.0130 | 14.9 | 8.5 | 3.7 | |
| hTAG | Cer 18:1;O2/16:0 | 35 (22/13) | 35 (20/15) | 0.4019 | 0.0086 | 0.2888 | 0.0062 | 12.7 | 12.8 | 5.8 |
| Cer 18:1;O2/18:0 | 34 (22/12) | 31 (20/11) | 0.0652 | 0.0015 | 0.0995 | 0.0020 | 13.5 | 11.0 | 5.6 | |
| Cer 18:1;O2/24:0 | 35 (20/15) | 36 (21/15) | 3.9250 | 0.0892 | 3.7641 | 0.0765 | 13.4 | 12.2 | 4.2 | |
| Cer 18:1;O2/24:1 | 34 (21/13) | 33 (20/13) | 1.2207 | 0.0400 | 1.2784 | 0.0267 | 19.1 | 12.0 | 4.7 | |
| DB | Cer 18:1;O2/16:0 | 33 (22/11) | 35 (21/14) | 0.3088 | 0.0060 | 0.2161 | 0.0052 | 11.2 | 14.3 | 5.5 |
| Cer 18:1;O2/18:0 | 35 (22/13) | 32 (21/11) | 0.0631 | 0.0014 | 0.0966 | 0.0020 | 13.3 | 11.8 | 5.0 | |
| Cer 18:1;O2/24:0 | 35 (20/15) | 36 (21/15) | 2.5252 | 0.0498 | 2.4013 | 0.0475 | 11.7 | 11.9 | 3.5 | |
| Cer 18:1;O2/24:1 | 35 (21/14) | 33 (21/12) | 0.8498 | 0.0308 | 0.8663 | 0.0173 | 21.4 | 11.5 | 4.4 | |
| YAA | Cer 18:1;O2/16:0 | 34 (21/13) | 34 (20/14) | 0.2127 | 0.0048 | 0.1450 | 0.0039 | 13.1 | 15.6 | 6.3 |
| Cer 18:1;O2/18:0 | 33 (22/11) | 34 (21/13) | 0.0331 | 0.0007 | 0.0494 | 0.0016 | 12.7 | 18.6 | 5.6 | |
| Cer 18:1;O2/24:0 | 34 (20/14) | 35 (21/14) | 1.7312 | 0.0318 | 1.6485 | 0.0375 | 10.7 | 13.4 | 3.5 | |
| Cer 18:1;O2/24:1 | 33 (21/12) | 33 (21/12) | 0.5333 | 0.0181 | 0.5518 | 0.0135 | 19.5 | 14.0 | 4.6 |
SOP and OTH refer to the standard and OTHER methods, respectively. n indicates the number of datasets that were included in the calculation of the variables given in this table after removal of outliers of the single-point (SP) or multi-point (MP) calibration, respectively, using Tukey’s 1.5 × IQR method (see text). The total number of datasets before removal was 39 (26 SOP/13 OTHER). Intra-lab %CV corresponds to the median of individual intra-lab %CVs.