Positive drug screening results are considered presumptive until a confirmation test, using an approved alternate method, is employed. Willow's stringent confirmation methods include dedicated Gas Chromatography/Mass Spectroscopy (GC/MS) testing in our in-house toxicology lab. Our GC/MS laboratory is the gold standard for confirmation testing in the industry. This methodology identifies specific drugs and can rule out false positive drug screens caused by prescription drugs, over-the-counter medications or other substances. GC/MS results are conclusive and therefore admissible in court. GC/MS testing ensures all initial test findings are confirmed in a quality controlled environment. GC/MS ensures your results are accurate and dependable. For an in-depth technological explanation, please call us - 781.268.2400. We are happy to discuss in great detail the science of GC/MS and all of our other technology.