![]() ![]() The National Institute of Drug Abuse and the Substance Abuse and Mental Health Services Administration publish recommended cutoff levels for drug testing which most companies follow. If your drug tests have high cutoff levels it is more likely for a user that has recently ingested drugs to produce a negative result. False Negatives From Very High Cutoff Levels Some doctors prescribe diazepam, oxazepam, and temazepam instead to reduce lab confirmations. Agents that follow a different metabolic pathway, such as triazolam, alprazolam, clonazepam, and lorazepam, have poor cross-reactivity with the assay due to the absence of these metabolites and thus frequently produce false-negative results. Most assays for benzodiazepines detect their presence in the urine by testing for nordiazepam and oxazepam, the main metabolites of most benzodiazepines. One study found that oxycodone was detected in 12% of opiate immunoassay tests, and many other synthetic or semi-synthetic opiates also require a special test for accurate results. The doctor has seen positive tests for opiates from his patients that are prescribed oxycodone, but his new patient tests negative. Many times a doctor prescribes their patient oxycodone or another semi-synthetic opiate, but uses a 5 panel drug test that only has a test for opiates. Every organization will have their own considerations when choosing a testing device, but some drug tests will not detect every illicit substance that people assume. ![]() Improper Drug Test SelectionĪ mistake made by organizations conducting drug tests is improper test selection. Many of these products will speed up the timeframe which a person can pass a urine screen even if it’s for no more reason than they’ve diluted their urine. These products range from nothing more than fortified tea that dilutes your urine to products that claim to seal in fat cells for several hours. ![]() There are several products available that claim to help users pass urine drug screens. Subjects can simply add water to their urine, but to fool a witness they will ingest an excessive amount of water to dilute the urine that comes from their own body. Without adulteration testing pure water will show negative on a drug test assay because the tests are only meant to detect the presence of a certain drug or metabolite in a substance, not to detect if the substance is a valid sample. When analyzing drug test samples, some color is preferable because urine that is completely clear cannot be distinguished from water without further testing. This chart shows how shades of urine relate to dehydration. You will need to perform separate adulterant tests for Creatinine, pH and protein levels to prove that a test has been diluted by a subject ingesting excessive amounts of water. Urine that is clear with no yellow tint is usually indicative of water loading. Water loading is the process where a person drinks an excessive amount of water prior to giving a sample. False Negatives From Water Loading & Adulteration The most common false negative drug test is due to water loading. In most cases this is caused by the patient either purposefully or accidentally altering their urine sample. An example would be a patient that is prescribed Oxycodone that takes his medication consistently as prescribed, but has a negative drug test during his doctor visit. What is a false negative on a drug test, what can you do to prevent them and what should you do if you identify one? What is a False Negative Drug Test?Ī false negative is any time that under normal circumstances a drug test would be positive for an individual but for some reason results are negative. Most people are familiar with false positives on drug tests, but are unaware of false negatives. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |