Table 3. Recovery Rates and Matrix Effects for CP-I and CP-III Concentrations in Human Plasma^a.

	CP-I			CP-III
nominal concentrations (ng/mL)	low QC sample	mid QC sample	high QC sample	low QC sample	mid QC sample	high QC sample
	0.03 + endo	15 + endo	40 + endo	0.03 + endo	15 + endo	40 + endo
recovery rate
analyte recovery rate [%, mean (range)]	44.6 [27.0–66.9]	46.2 [32.4–76.1]	41.4 [28.8–74.0]	95.5 [26.5–364.8]	79.4 [28.4–280.1]	36.1 [23.0–67.8]
recovery rate corrected by internal standard [%, mean (range)]	96.8 [87.1–111.0]	93.9 [87.4–102.9]	95.1 [85.7–101.3]	93.7 [79.0–108.7]	93.3 [84.5–106.7]	92.0 [83.6–98.4]
matrix effect
analyte matrix effect [%, mean (range)]	116.7 [92.3–156.2]	110.6 [104.4–115.2]	106.2 [92.4–116.4]	120.0 [58.4–203.2]	119.0 [106.4–134.8]	113.7 [98.2–128.8]
matrix effect corrected by internal standard [%, mean (range)]	101.3 [83.6–119.1]	111.0 [99.5–117.3]	102.9 [98.4–106.9]	88.0 [81.1–92.4]	110.2 [100.0–117.7]	105.6 [96.5–110.1]

^aCP-I, coproporphyrin-I; CP-III, coproporphyrin-III; QC, quality control; Endo, endogenous level.