Table 3. Inter- and intra-day performance.

Inter-day mean ± standard deviation (Std Dev), accuracy (% error), and precision (% CV) were determined for 208 blinded PT samples for 5 LF levels analyzed over 17 days for both the 4-h and ON methods (A). For blinded samples analyzed 3 or more times a day, the intra-day means, % error and % CV were determined daily, then mean ± Std Dev, for the daily results were determined (B).

A. Inter-Day Precision and Accuracy (17 Days Total)
LF PT (ng/mL)	0.721	0.383	0.204	0.108	0.058
N	40	43	41	42	42
Fast (4-h) Inter-Day
Mean ± Std Dev	0.708 ± 0.072	0.380 ± 0.039	0.197 ± 0.021	0.107 ± 0.014	0.058 ± 0.014
% CV	10.2	10.3	10.6	13.1	23.6
% error	1.9	0.72	3.5	1.3	0.2
Overnight Inter-Day
Mean ± Std Dev	0.661 ± 0.072	0.345 ± 0.037	0.184 ± 0.017	0.102 ± 0.010	0.056 ± 0.0047
% CV	11.0	10.7	9.0	9.9	8.5
% error	8.5	9.8	9.6	5.1	3.8
B. Intra-Day Precision and Accuracy
LF PT (ng/mL)	0.721	0.383	0.204	0.108	0.058
N Days	5	8	8	9	9
N Samples	17	25	24	27	27
Fast (4-h) Intra-Day
Mean ± Std Dev	0.693 ± 0.047	0.383 ± 0.024	0.190 ± 0.033	0.104 ± 0.21	0.058 ± 0.015
% CV	4.2 ± 3.1	6.0 ± 3.8	7.5 ± 3.8	7.1 ± 4.2	10.7 ± 9.0
% error	3.9 ± 6.5	5.5 ± 2.3	7.5 ± 5.1	6.9 ± 8.4	10.8 ± 18.2
Overnight Intra-Day
Mean ± Std Dev	0.649 ± 0.032	0.342 ± 0.031	0.187 ± 0.012	0.104 ± 0.007	0.056 ± 0.003
% CV	5.1 ± 3.0	6.4 ± 2.5	8.0 ± 4.4	6.3 ± 7.0	5.3 ± 5.7
% error	10.0 ± 4.5	10.6 ± 8.0	8.7 ± 5.3	3.6 ± 7.2	3.0 ± 6.0