Table 1.

New cannabis use model parameters developed with all urine creatinine normalized (CN)-11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) excretion data from the model development group of 48 chronic heavy cannabis users during up to 30 days abstinence on a closed research unit. Specimen 1 groups are based on CN-THCCOOH urine concentrations.

Specimen 1 CN-THCCOOH concentration (ng/mg)	N	Model Parameter
		A	k	RMS
6–14.9	3,317	1.244	0.00160	0.513
15–24.9	7,150	0.994	0.00087	0.282
25–49.9	21,790	1.018	0.00131	0.264
50–99.9	49,052	0.891	0.00086	0.174
100–199.9	29,695	0.664	0.00129	0.064
200–399.9	10,488	0.384	0.00144	0.014
400–599.9	1,066	0.213	0.00188	0.003
600–1166	955	0.212	0.00342	0.001

N = number of paired urine CN-THCCOOH concentration ratios

RMS = Residual mean square

A = Linear parameter in exponential model

k = Nonlinear parameter in exponential model