The toxicology test determines the approximate amount and type of legal / illegal drugs that the client has taken. We use it to screen for drug abuse, to monitor a substance abuse problem, or to evaluate drug intoxication or overdose. The results can show the presence of one specific drug or a variety of drugs at once. Further testing may be needed to determine the exact amount of a particular drug in the body and to confirm the results. Many substances can be discovered through toxicology screening, including: