Blood drug tests
Often used to test specifically for illegal substances, blood drug tests measure the precise amount of drugs and/or alcohol that are found in the blood sample. Blood tests accurately detect the presence of illicit drugs, but the samples are much costlier to collect. Taking blood samples and sending them to be analyzed is a more time-consuming procedure, whereas some urine tests can be taken and analyzed within minutes. Blood drug tests require the equipment and qualified personnel to draw the blood, handle and label it, test it, and finally to record and analyze the results.
Upon a failed drug test (of any type), another type of drug test is immediately done to confirm these results. This second type of drug test can be any other type of drug test, but is usually a gas chromatography. A “GC”, as they are called, is a more expensive method of drug testing, but one that produces extremely specific and accurate results. One of the drawbacks of a blood test is the window of time which it allows to be tested. Some substances exit the body quicker than others, and some residues are harder to trace. Hair follicles allow for a much wider window, as evidenced below.
Hair drug tests
Hair drug testing is widely considered to be one of the most accurate drug testing methods. Hair drug tests can easily and frequently be replicated, so tests can be repeated with the same conditions as often as desired. In addition, hair tests are not very intrusive. Traces of drugs appear in hair shafts within five to seven days after initial drug use, and remain for months. By testing for drugs within the hair shaft as opposed to bodily fluids, labs are able to further backdate any potential substance abuse.
Saliva and sweat can test falsely negative after simply abstaining from the substance for a short time, whereas hair does not lose the trace nearly as fast. Many courts of law also use hair drug testing as a regular method for people on probation programs or for other people that require regular drug screenings. The standard measure of hair for a screen is anywhere from 1.0-1.5 inches of hair. This small section of hair can provide a reliable test range of several months for drug testers. Illegal drugs that are screened for in a hair drug test include, but are not limited to – marijuana, PCP, cocaine, opiates, methamphetamines, and ecstasy.