I'm going to focus on on particular drug - Methamphetamine.
There are different detection periods for each test. With urine meth can be detected in it for 3-5 days. With a hair sample meth will stay there for a complete 90 days.
A big problem with urine is urine cannot detect current drug use. It takes approximately 6–8 hours or more post-consumption for drug to be metabolized and excreted in urine. Similarly, hair requires two weeks.
Urine test procedure: The first step at the testing site is to split the urine into two samples. One sample is first screened for drugs using an analyzer that performs immunoassay as the initial screen.
A immunoassay is a bio-chemical test that measure the concentration of a substance. If the urine screen is positive then another sample is used to confirm the findings by gas chromatography which is a method used to seperate molecule for analysis. And I'm sure we all know about the high possiblities with a false-positive with urine
Hair test: Any drugs taken are encased in the hair shaft. Meaning that if a hair sample is taken there it no way to spike it or take something out of it. An the hair cannot be watered down. Longer hair can give more drug history. Many people believe that if they shave their hair then it will void the test. But many don't think about the other hair they have on their body. Like from the face, chest, or arm pit. leg hair is also good because it has alot slower growing period.
The reasons durg show up in hair is because hair growth is fed by our bloodstream. With the possibility of there being no hair on the body hair folicles can be used in place of the hair. Radioimmunoassy is used for hair testing. testing facilities are regulated by SAMHSA.
Hair testing is far better than urinalysis for many reasons.
-Hair testing results cannot be altered with shampoos or other external chemicals.
-wider window of detection.
-inability to tamper with the test.
-Methamphetamine is excreted and usually undetectable in urine 72 hours after use. The detection period for hair is limited only by the length of the hair sample and is approximately 90 days for a standard test.
-there are no known adulterants for hair tests. Since hair tests analyze the drugs inside the hairshaft, external contaminants/chemicals have no effect.
-It takes approximately 4-5 days from the time of drug use for the affected hair to grow above the scalp. And it stays there.
-In side-by-side comparison studies with urinalysis, hair drug testing has uncovered significantly more drug use. In two independent studies hair drug testing uncovered 4 to 8 times as many drug users as urinalysis.
-Hair is relatively inert, easy to handle, and requires no special storage
facilities or conditions.
-Collecting comparable samples for repeat testing is easier with hair than
Once a drug metabolite is embedded in the hair sheath, a process which
appears to occur while the hair is being formed in its follicle, the
metabolite is very nearly permanent. As the hair shaft grows, it forms a
longitudinal record of the compounds it has absorbed, including drugs of
Drug metabolites appear in detectable levels in hair approximately a week
after ingestion. Hair grows at an average rate of about half an inch
every 30 days. The hair shaft can be cut into various lengths, allowing a
"time line" analysis of drug consumption. Like a tape recording, a hair
specimen can allow an analyst to construct a history of drug use This "tape
recording" presents an expanded time-monitoring window in contrast to single
urine specimens collected at widely spaced intervals.
Once the hair is taken it will probably put an end to the Mayfield/NASCAR saga. But, we can only hope for that. It's very clear to see the only way to go here is hair.