Drug Testing FAQs
Can I pass a home drug test and still fail a laboratory test?
Yes. You can have a negative home drug test and a positive laboratory test. Different substances, cut-offs, testing methods or collection times can explain the difference. A home screening result cannot guarantee the outcome of a later test.
Different panels and cut-offs
A multi-drug kit only checks the substances listed in its instructions. A laboratory panel may include drugs or metabolites, the substances your body produces when processing drugs, that your home kit does not cover.
Each test has a cut-off, the concentration used to report a positive or negative result. A laboratory method with a lower cut-off may detect something below the home kit’s threshold.
Samples and methods can change the result
Urine and saliva have different detection windows. Even two urine samples collected at different times can contain different concentrations, so the results are not directly interchangeable.
Many home kits use antibody-based screening. Laboratory confirmation uses more specific methods, such as mass spectrometry. However, a laboratory may start with a screening test rather than automatically perform confirmation.
What to check when results disagree
Compare the substance panels, cut-offs, sample types and collection dates. Check that you followed the home kit’s instructions and read the result within its stated time window.
Ask the testing provider if the laboratory result is preliminary or confirmed. An unexpected screening result should be reviewed and, where appropriate, confirmed before decisions are made. Repeating a home test is not laboratory confirmation.
Planning a home drug test?
Know what your kit can tell you.
Compare Rezure’s drug testing kits by the substances covered and sample type. Check each kit’s intended use before ordering, and remember that a home screening result cannot predict a later laboratory result.
Need help finding a kit’s substance list or instructions? Contact our team with the product name so we can point you towards the relevant information.
Compare Drug Test Kits