Table 2.

Predicted elapsed time between cannabis smoking and blood collection with plasma THC ≥0.5 μg/L and THCCOOH ≥2.5 μg/L.

nAccuracy (samples within 95% CI), %Elapsed time overestimatedElapsed time underestimated
nMean (range) time, minnMean (range) time, min
Model I
 Single dose42791.83514 (<1 to 41)0
 Multiple doses29090.32518 (<1 to 50)35 (2–11)
 All cases71791.26016 (<1 to 50)35 (2–11)
Model II
 Single dose41594.043 (<1 to 6)2138 (2–94)
 Multiple doses28997.672 (<1 to 4)0
 All cases70495.5112 (<1 to 6)2138 (2–94)
Combination of models I and II1
 Single dose41599.521 (<1 to 1)0
 Multiple doses28998.642 (<1 to 4)0
 All cases70499.162 (<1 to 4)0