Urine drug testing is the most common way of workplace testing for specific drugs because it is not invasive, and samples are easy to collect. Drug tests either test for the parent drug or at least one of its metabolites, or both. Concentrations of drugs in urine are usually higher than in blood and present for longer. There are two main types of urine drug tests: screening and confirmatory tests.
Immunoassay screening tests can be conducted on-site (point of care testing) or in a laboratory and allow large numbers of tests to be performed at once with relatively rapid results, providing an initial estimate of the presence or absence of drugs. There are three main types available, and all use antibodies to detect the presence of specific or classes of drug metabolites. Unfortunately, this can mean that substances with similar characteristics may be detected, resulting in false-positive results. Some visual point of care tests are favored by pain management clinics or by clinicians treating people with substance misuse disorders. However, at times the results may be difficult to read (such as a faint color or an uncertain color) which can result in a subjective interpretation. These tests should only be considered preliminary and a follow up confirmatory laboratory test should be conducted, as with any screening test; however, this best practice may not always be followed. Confirmatory tests (Drug of Abuse Panel tests) use gas chromatography/mass spectrometry to identify specific molecular structures and to quantify the amount of drug or a substance present in the sample. These are more accurate than screening tests, but are also more costly and time-consuming and are usually reserved for situations that have significant legal, academic, forensic, or employment sequelae. These recognize cannabinoids rather than metabolites so should be able to distinguish CBD from THC.
Ichthammol, for example, traces back to the 19th century, explained Boyd who wrote a review article on the topic for the International Journal of Dermatology in 2010. And while there hasn’t been much written about it, there are historical accounts of sulfonated shale oil being used to aid in wound healing that go back as far the 1400s, Boyd said. Then in the late 1800s, a dermatologist wrote about the salve, recommending its use in the treatment of eczema. Style 12 face and body moisturizers to save dry skin this winter. And while it may indeed help with eczema, there’s “much better stuff being used today,” Boyd said. Moreover, Boyd noted he’s yet been able to find any double blind placebo controlled trials — the gold standard in medicine — testing ichthammol’s efficacy. The good news, he added, is that the product doesn’t seem to have any significant side effects. Like many home remedies, salves are mostly benign — the exception being the use of “black salve” for treating skin cancer. Black salves “are made from completely different chemicals,” than ordinary salves, Boyd said. “They kill skin cells indiscriminately.” So while a black salve can indeed obliterate cancerous lesions that aren’t life-threatening, “so will a blow torch,” Boyd said, adding that he’s seen people “with big divots in their skin the size of a nickel to a silver dollar.” Black salve is definitely bad news for skin, said Dr.
Shari Lipner, a dermatologist at NewYork-Presbyterian and Weill Cornell Medicine in New York City. “Patients are getting information off the internet that says it will cure skin cancers,” Lipner said. “It has a host of ingredients, including zinc chloride and sanguinarine.