Sweat patch testing is used primarily in drug-related court cases. Occasionally, this form of testing is also used by families who wish to privately perform surveillance or intervene with loved ones they suspect of drug use.
Rarely do employers use it, even though the U.S. Department of Health and Human Services in 2004 proposed revisions to the Mandatory Guidelines for Federal Workplace Drug Testing Programs. These revisions, approved and published in 2008 and under effect since 2010, made it legal for employees to use sweat patch testing for the following situations:
- Pre-employment screening
- Random testing
- Reasonable suspicion
- Returning to work tests after an absence or accident.
In many cases, this type of testing is a better choice than the more commonly used urine testing, for the following reasons:
1. Longer testing time
The greatest advantage to sweat patch is the 1-14 day testing window. Standard urine-based test strips may be better for immediate results, but they only detect drug indicators currently in the system.
The longer testing window helps when catching the most common drugs – like marijuana, cocaine, methamphetamines, LSD, and heroin – which generally stay in the system of occasional users for about five days.
The National Institute on Drug Abuse notes that many clear from the system in as little as two days. Therefore, repeated urine tests over the course of several days and weeks are often needed when monitoring suspected drug users. The lengthy window of a single test is a major reason many court systems favor sweat patch testing.
The sweat patch we use, from PharmChem, Inc, is coated with an outer membrane composed of a polyurethane film with an adhesive that keeps the patch sealed on the skin for up to two weeks.
2. No urine collection necessary unless results are positive
Applying the sweat patch is quicker and more hygienic, than immunoassay urine tests. For test subjects with negative results, the urine collection step is skipped entirely.
As with urine strip tests though, any positive result from a sweat patch must also be confirmed by GCMS analysis in which the GCMS machine converts a urine sample from liquid to gas and searches for indicators of various drugs.
3. Improved accuracy
Proved through controlled tests of both non-drug and drug users false negatives are uncommon. In fact, most false negatives are usually due to the patch being delicate enough to pick up residual drugs in the body from past drug use, and in these cases, GSMS can prove that individuals are not currently using illicit substances.
When urine test strips are used, one report notes false positives as high as 21% when used by doctors and Drugs.com notes that false positives frequently occur with home testing strips or workplace testing kits.
4. Superior results
Urine testing can often miss the detection of drugs as they can only detect the metabolite – the part of the parent drug broken down by the metabolism. Sweat patches also detect the parent drug.
When a test subject uses drugs occasionally, urine test strips often to not catch drugs which have already metabolized. Unless the subject is using frequently enough to steadily build up a consistent amount of metabolite in their body. Consequently, sweat patches are a better option as they can catch both types of users.
5. No undetected substitution, dilution or adulteration
Sweat patches are designed so that, once applied, they cannot be removed or altered. Tampering is a common concern for urine tests and sometimes an issue with hair testing. Thus, sweat patch results, when confirmed by a GCMS test, are a better source of evidence for the court system.
6. Better than ever
Sweat patch testing has been used for over 20 years. The membrane of the outer surface has evolved with new technology to make contamination through permeability highly unlikely. Additionally, advanced technology in sweat patches increases the typical 7-10 day maximum for sweat patches to up to 14 days.
If sweat patches seem like a testing option you’d like to consider, contact us via email or call our Beaumont office at (409) 212-9706 or our Bridge City office at (409) 444-2104.