| Samples | Added (µmole/L) | Found (µmole/L) | Recovery (%) |
| Serum 1 | --- 4.524 × 10−2 1.345 × 10−1 | --- 4.842 × 10−2 1.388 × 10−1 | --- 107 ± 2 103 ± 2 |
| Serum 2 | --- 4.524 × 10−2 1.345 × 10−1 | --- 4.64 × 10−2 1.354 × 10−1 | --- 102 ± 2 100 ± 2 |