Table 1.

Accuracy and precision of the combined assay for NNN and NNAL in urine^a

Nominal concentration (pmol/ml)	Intra-day			Inter-day
	Foundb (pmol/ml)	% RSD	% Deviation from nominal	Foundc (pmol/ml)	% RSD	% Deviation from nominal
NNN
0.015	0.0161	10	7.4	0.0165	16	9.8
0.040	0.0396	5.4	−1.0	0.0400	14	−0.1
0.100	0.0963	3.3	−3.7	0.0965	15	−3.5
0.300	0.290	1.9	−3.4	0.291	16	−3.1
NNAL
0.075	0.093	3.4	24	0.0897	11	20
0.200	0.210	2.5	4.8	0.207	11	3.4
1.00	1.03	2.4	2.7	1.003	12	0.30
3.00	3.06	2.1	2.1	3.03	12	1.0

^aFour different amounts of NNN or NNAL were added to pooled urine samples from 5 non-smokers and the analysis was performed 6 times on one day (intra-day) or 6 times on each of 3 days (inter-day).

^bmean of 6 determinations at each level

^cmean of 18 determinations, 6 at each level on 3 separate days