Table I

Intra- and interday validation statistics

Nominal concentrationIntraday variation (n = 3)aInterday variation (n = 8)b
Determined concentration (mean ± S.D.)PrecisioncAccuracydDetermined concentration (mean ± S.D.)PrecisioncAccuracyd
ng·ml−1%%%%
54.92 ± 0.438.82−1.674.95 ± 0.469.23−0.88
1011.00 ± 0.958.6710.0010.72 ± 0.736.847.21
2021.27 ± 1.075.036.3320.41 ± 1.014.942.06
4037.2 ± 1.644.40−7.0038.72 ± 1.624.20−3.19
  • a Intraday variation was evaluated across three biological replicates per concentration point: 100 μl of blank female serum was spiked with PSA and then submitted to albumin depletion, trypsin digestion of the peptides, and fractionation by MCX.

  • b Interday variation was evaluated across eight biological replicates per concentration point over a 3-month period different from those used for the interday variation: 100 μl of blank female serum was spiked with PSA and then submitted to albumin depletion, trypsin digestion of the peptides, and fractionation by MCX.

  • c Expressed as relative S.D.: (S.D./mean) × 100.

  • d Expressed as percent difference:((concentration found − concentration added)/concentration added) × 100.