Drug testing through the collection and testing of biological samples including fingernails, toenails, sweat, saliva, blood, and urine is common practice. Urine sampling is often the most popular due to its ease of collection and the fact that chemical concentrations in the urine tend to remain high for a relatively long period. There are two over-arching terms used to describe urine testing — Urinalysis, and Full Examination and Microscopy Examination (FEME) urine drug screening. Here are the primary differences between the two methods of urine testing.
A urine test, or urinalysis, is done to diagnose or monitor a medical condition. It is commonly used to detect abnormalities or the presence of chemicals in urine. Urinalysis includes testing for kidney stones, kidney or liver disease, diabetes, or as a component of a pregnancy checkup. A urine test is often used as part of a routine medical exam, or as part of a regular pre-surgery procedure. Tests are also required due to symptoms related to urinary tract problems. These symptoms might include pain in your stomach or back, needing to urinate frequently, or blood in your urine. There are three critical components to urinalysis procedures:
This check looks at the color, clarity, and appearance of the urine. Unusual color or transparency can be an indicator of a disease, blood, or liver malfunction. Certain foods like beets or foods with added dyes can affect the color of the urine sample and should be avoided, if possible, before testing.
2. Chemical Analysis (immunoassays)
Chemical analysis with the use of a single or multi-panel test strip or dipstick is used to check out a variety of components like pH, blood leukocytes, proteins, blood glucose, and nitrites. A change in color on the test strip can be an indicator of a chemical present in the blood — the more saturated the color, the more presence of a chemical. A dipstick is used as a conclusive test for a variety of urinary conditions and a screening test for others. It is often used to determine whether a microscopic analysis is required.
The third component of the test involves a microscopic analysis of urine samples to look for abnormalities including blood cells and bacteria. The presence of crystals may be an indicator of kidney stones.
Full Examination And Microscopy Examination (Urine FEME) Drug Screening
Urine FEME testing is a comprehensive examination that analyzes all urine components to determine whether or not chemical substances, including drugs and banned substances, are present. Like a urinalysis used for strictly medical purposes, there are three parts to the examination — visual, chemical analysis, and a laboratory examination.
The significant difference in the procedure between a medical urinalysis and urine FEME drug screening is in the area of chemical analysis, where customized test strips or dipsticks are used to determine the potential of banned chemicals in the subject’s system, followed by a laboratory examination using gas chromatography/mass spectrometry (GC/MS0).
It is essential to make note of any prescribed medications that may affect the procedure. Often an automated system is used to read the strip to minimize errors and interpretation. There are several advantages to the test. Firstly, it is inexpensive and relatively simple. There are a variety of single and multi-panel test strips available that will allow for the testing of a particular substance or multiple substances. Secondly, the preliminary results are instantaneous.
Single or multi-panel drug screen tests can be used to quickly access the type of drug in the urine sample including cannabis, cocaine, opiates, methamphetamines, Phencycladine (PCP), and Oxycodone. (Learn more in Drug Test Types: When To Use 5, 7 or 12 Panel Urine Screening). Suppliers offer strips with a variety of drug combinations to provide customized results. The pH level of urine is also an essential factor analyzed with this method. Typically, human urine has a pH level that varies between 4 and 8 throughout various times of the day. A pH reading of below 3 or above 11 can indicate a contaminated sample.
Laboratory analysis and confirmation is required
While dipsticks can be a reliable indicator of drug and chemical presence, all results are classified as presumptive until there is a laboratory analysis of the sample to confirm the specific drug. It should be noted that false positive and false negative indicators can be the result of a faulty test strip that is old or has not been kept in a sealed container and thus has been been exposed to the air. It is also possible that the dipstick may not pick up on all opioids.
Common issues with urinalysis and FEME urine drug screening
Several factors, including prescribed and over-the-counter medication, prior food consumption, and potential contamination, will affect the quality of the sample. Early morning urine collection is generally preferred, as it provides a more concentrated sample. If a positive test result indicates the use of banned substances that have not been taken, it is important to follow-up with a GC/MS immediately. Although urine testing for medical conditions or drug use is common practice and has several advantages, preliminary visual and chemical indicators should always be followed-up with laboratory confirmation.