Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is the world's most widely consumed psychoactive drug. It is found in the seeds, nuts, or leaves of a number of plants native to South America and East Asia and confers on them several survival and reproductive benefits.
Caffeine can produce a mild form of drug dependence–associated with withdrawal symptoms such as sleepiness, headache, and irritability – when an individual stops using caffeine after repeated daily intake. After intravenous administration of caffeine the urine level of the drug is approximately the same in each of the first 4 hourly specimens. In addition, flu-like symptoms, nausea/vomiting, and muscle pain/stiffness were judged likely to represent valid symptom categories. In experimental studies, the incidence of headache was 50% and the incidence of clinically significant distress or functional impairment was 13%. Typically, onset of symptoms occurred 12–24 h after abstinence, with peak intensity at 20–51 h, and for a duration of 2–9 days. 1% to 3% of caffeine is excreted unchanged in the urine. The rate of caffeine metabolism is variable, with a half-life of 4 to 6h.
NEGATIVE :Two lines appear. One color line should be in the control region (C), and another apparent color line should be in the test region (T). This negative result indicates that the specimens concentration is below the detectable cutoff level.
NOTE : The shade of color in the test region (T) may vary, but it should be considered negative whenever there is even a faint color line.
POSITIVE : One color line appears in the control region (C). No line appears in the test region (T). This positive result indicates that the specimens concentration is above the detectable cutoff level.
INVALID: Control line fails to appear. Insufficient specimen volume or incorrect procedural techniques are the most likely reasons for control line failure. Review the procedure and repeat the test with a new test kit . If the problem persists, discontinue using the test kit immediately and contact your local distributor.
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