Table 3. Spiking recovery.

COL-18N	Serum Recovery	Heparin plasma Recovery	Citrate plasma Recovery	EDTA plasma Recovery
Matrix neat + spike	92%	112%	108%	116%
Matrix diluted 1:2 in buffer + spike	106%	110%	103%	106%
Matrix diluted 1:4 in buffer + spike	107%	105%	95%	106%
Matrix diluted 1:8 in buffer + spike	102%	103%	110%	107%
Mean recovery	102%	108%	104%	109%

Spiking recovery was calculated as percentage recovery of measured spike (80 ng/ml standard peptide added) in buffer compared to measured spike in matrix, subtracted diluted matrix value.