There are two generally accepted types of urine test kits on the market, on-site tests and off-site tests. An on-site test is one that provides almost instant results, and an off-site test requires laboratory verification and can take a week or more for the results to be analyzed and delivered. On-site urine test kits are used for both drug and alcohol screenings. Off-site testing typically is limited to screening for substance abuse.
On-site urine test kits typically are found on job sites that practice random drug testing. A urine specimen is collected, and a test strip is placed in the sample and allowed to sit for a few minutes. When the results are ready, the various colors on the test strip will indicate the presence of drugs in the urine, if any are detected. Instant results often are needed after workplace accidents, because many liability insurance providers require testing immediately following an incident to determine where substance use played a factor.
On-site tests also can be used to test for recent alcohol usage. Alcohol screenings are particularly useful in jobs that prohibit alcohol consumption within a set time frame before a shift starts. Airline pilots, heavy construction machinery operators and people in other high-risk, high-responsibility positions typically are subject to random alcohol tests to verify that these regulated standards are being adhered to.
Off-site urine test kits use the same method of specimen collection as on-site kits. Specimens usually are collected at an approved facility in order to better ensure that the specimen used in the drug screening is not subject to any potential contamination or alterations. Specimen collectors are trained to test for the urine's temperature and concentration levels in order to reduce the chance of alterations to the specimen. After these details have been verified, the specimen is sealed and sent to an off-site laboratory for analysis.
After the specimen is received at the laboratory, the sample is split into two parts. The first half is tested using an immunoassay analysis. If the results show potential presence of illegal substances, a second test is performed on the remaining half of the sample using gas chromatography and mass spectrometry to verify the positive reading. The use of a second round of testing and complex, scientific testing methods greatly reduce the chance of a false positive reading.
Urine test kits screen for a variety of substances, such as cocaine, barbiturates and heroin. The amount of time that trace amounts of specific substances will appear in the urine will vary from drug to drug. Potential detection times can range from a few hours to several weeks after the drug was used.