Mr. Toast is right. The EMIT/EIA 50 ng/ml cutoff is functionally equivalent to the GC/MS 15 ng/ml cutoff. The GC/MS is not more likely to come up positive.

EDIT:
Also, the lightness/darkness of your test line is not indicative of more/less drug metabolite concentration. If you can see the line, you're negative.

What the lightness/darkness really indicates are the pre-determined cutoff levels. The line on a marijuana test is very light because it's only looking for a small concentration (50 ng/ml)... whereas a drug that needs a higher concentration (say, 1000 ng/ml) will usually show a relatively darker test line when you pass.

You can drop a 5-panel home test in clean urine and the THC line will almost always come up far more pale than the other drugs.
budcloth64 Reviewed by budcloth64 on . Passing a Quest Diagnostics UA Drug Test This is my experience in passing a Quest Diagnostics UA Drug test for a UR Drug Screening 6405N SAP 550 GC/MS. I recently graduated from college and within about 5-6 weeks got a great job offer. I started smoking in college my sophomore year and after that first year I became a heavy user. Smoking everyday several times a day for about 3 years straight. I quit smoking after Christmas to prepare for the chance that I would be tested for a job. I took about 3 at home drug tests during this Rating: 5