Table 1.
Assay accuracy and precision (%CV) of LLOQ, LQC, MQC, and HQC samples for cyclocreatine, creatine, creatine‐d3, phosphocyclocreatine, and phosphocreatine
| Analyte | n = 6 | LLQC (0.5 ng/mL) | LQC (5 ng/mL) | MQC (50 ng/mL) | HQC (1000 ng/mL) |
|---|---|---|---|---|---|
| Cyclocreatine (cCr) | Mean (ng/mL) | 0.485 | 5.04 | 51.6 | 992 |
| Accuracy (%) | 97 | 101 | 103 | 99 | |
| Precision (%CV) | 10.6 | 2.7 | 3.2 | 5.4 | |
| Creatine (Cr) | Mean (ng/mL) | 0.531 | 5.38 | 52.0 | 1010 |
| Accuracy (%) | 106 | 108 | 104 | 101 | |
| Precision (%CV) | 3.9 | 7.8 | 3.0 | 5.1 | |
| Creatine‐d3 (Cr‐d3) | Mean (ng/mL) | 0.506 | 5.27 | 51.3 | 968 |
| Accuracy (%) | 101 | 105 | 103 | 97 | |
| Precision (%CV) | 6.8 | 4.0 | 3.5 | 4.9 |
| Analyte | LLQC (10 ng/mL) | LQC (100 ng/mL) | MQC (1000 ng/mL) | HQC (10 000 ng/mL) | |
|---|---|---|---|---|---|
| Phosphocyclocreatine (pcCr) | Mean (ng/mL) | 10.0 | 92.0 | 1020 | 10 200 |
| Accuracy (%) | 100 | 92 | 102 | 102 | |
| Precision (%CV) | 15 | 6.0 | 4.3 | 3.9 | |
| Phosphocreatine (pCr) | Mean (ng/mL) | 10.1 | 100 | 1010 | 9580 |
| Accuracy (%) | 101 | 100 | 101 | 96 | |
| Precision (%CV) | 4.2 | 9.1 | 6.2 | 7.6 |