Sample Concentration spiked (mg/L) Concentration found (mg/L) (Mean ± SD) Bias (%) Imprecision CV (%)
Flucloxacillin    
  LLOQ 0.200 0.190 ± 0.0136 -4.9 7.2
  QC1 2.00 1.86 ± 0.090 -6.8 4.8
  QC2 20.0 18.7 ± 0.81 -6.6 4.3
  QC3 100 101 ± 5.53 1.3 5.5
Cefazolin    
  LLOQ 0.200 0.212 ± 0.0142 -5.8 6.7
  QC1 2.00 2.00 ± 0.135 0.0 6.7
  QC2 20.0 19.9 ± 0.61 -0.3 3.0
  QC3 100 101 ± 4.61 1.5 4.5
Table 1: Intra-day assay variance of the determination of flucloxacillin and cefazolin in plasma (n = 6).