Table 4. Matrix effects from different donors in heparin plasma.

Donors A to F are individual donors collected using sodium heparin as anticoagulant.

Concentration/ Donor:	A	B	C	D	E	F	Average	SD	RSD
QC 1, 2.97 µg/ml	1.12	1.18	1.10	1.03	1.07	1.03	1.08	0.057	5.27%
QC 3, 155 µg/ml	0.93	0.87	0.93	0.91	0.93	0.88	0.90	0.027	2.96%
IS for QC 1, 2 µg/ml	0.99	1.03	1.00	1.01	1.01	1.01	1.01	0.013	1.32%
IS for QC 3, 2 µg/ml	1.01	1.05	1.03	1.05	1.01	1.03	1.03	0.016	1.59%
Normalised QC1/IS	1.13	1.15	1.10	1.02	1.06	1.02	1.07	0.057	5.30%
Normalised QC3/IS	0.93	0.84	0.90	0.87	0.92	0.86	0.88	0.036	4.12%

QC, Quality Control; IS, internal standard. Values less than 0.85 or higher than 1.15 would imply a matrix effect. However, if a matrix effect is present, then the RSD calculated from the different blank lots of matrices, should not be greater than ±15%.