What is the confirmatory test for THC?
What is the confirmatory test for THC?
Confirmatory testing is usually performed with an instrument called a mass spectrometer. Types of mass spectrometry tests used for confirmatory testing include gas chromatography/mass spectrometry (GC/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS).
How can I get a false negative for THC?
False-negatives can occur when the urine drug concentration is below the threshold level set by the laboratory performing the test. Dilute urine, the duration of time between ingestion of the drug and time of testing, and the quantity of the drug ingested may affect the occurrence of false-negatives.
What is the normal THC-COOH level after negative drug test?
This study also reported that on average, the urine THC-COOH levels reached a peak of about 100 ng/mL after testing negative at the 50 ng/mL level. Although the highest subject reached 289 ng/mL, about a 6-fold increase!
How long after smoking marijuana can you get a negative test?
Typically, the threshold is 50 ng/mL. As long as you register under this value, your test result will be negative. Drug testing within 24 hours after using marijuana can be risky. However, there are ways to improve your chances and even make sure that you will test negative.
Why did I fail a urine test for THC?
Or perhaps you were working outside and lost a lot of fluids through sweating, which can also lead to more concentrated urine and a test failure. The plots above already control for urine output level by normalizing the THC metabolite values to urine creatinine.
Do the screening tests measure both free and conjugated THC metabolites?
Since the screening tests are immunologically based and measure both conjugated and free forms of THC metabolites, any confirmatory procedure should either measure both forms or should include a hydrolysis step to increase analytical sensitivity.
