I emailed the manufacturer about my 1st test, I obviously had some question that perhaps were also lingering with you folks, here is what they had to say:

Thank you for contacting First Check Diagnostics regarding our Home Drug Test Product Line. We appreciate your business and value your feedback. We are happy to address any questions or concerns you may have with our First Check products.

The First Check Home Marijuana and Methamphetmaine test is a Thin Layer Chromatography (TLC) test. Our cut-off level for THC is 50ng/mL, but I do not know what cut-off level another lab may use. If another test used a lower cut-off level than we did, it would be a more senstive test.

All First Check Home Drug Tests are at least 98% accurate in detecting drugs in urine. However we cannot guarantee a Negative Result on another test because each result can vary due to:

1) The cut-off level used – other tests may use a lower cut-off level.

2) The way the drug is metabolized – drugs clear the body at different intervals.

3) Excessive fluid intake prior to testing – could dilute a drug in the urine making it more difficult to detect.

4) Timing of test – when the drug was taken in relation to testing.

A Negative test result means one of two things:

1) There was NO drug present in the urine sample or,
2) There was NOT ENOUGH drug present in the urine sample to be considered a Positive as the amount was below the designated cut-off level.

Our screening tests may not detect amounts of drugs in a urine sample that are below our established cut-off levels. Therefore, even though some level of drug may be present in the urine sample, the sample would still be considered a Negative Result if the drug level is below the cut-off level.

If you have any further questions or comments, please feel free to reply to this email or call our toll-free Help Line at 1-888-788-5716. Our First Check Help Line Specialists are available to assist you, Monday through Friday from 8:30 A.M. to 5:00 P.M. Eastern Time.

Sincerely,

Mavourneen Fay
First Check Helpline Specialist