I am at 30 days + and still at 193 ng and 50 ng is passing in my state.
This only applies to the initial assay screen which has no ability to give a quantitative figure. When the confirmation GC/MS is performed (which does give a quantitative analysis), the cutoff threshold is 15 ng/ml.

Because of its accuracy and its ability to quantify, the GC/MS is the methodology whose results will stand up in any court jurisdiction.