The Truth About Saliva Drug Testing

Saliva drug testing is a great alternative to urine screening, however it does have it’s drawbacks.  Here are a few facts about oral fluid drug screening.

Saliva screening has become a popular method of drug testing in recent years.  The need for validity tests with oral fluid testing is minimized because of the observed collection process.  Furthermore,  it elevates the situation of male testing female and vice versa.

In general the detection times for oral fluid drug testing are less than urine drug testing.  For example, many drugs (cocaine, opiates, methadone,  and amphetamine) are detected in urine for up to three days after cessation of use; they are detected in oral fluid for up to two days.  THC metabolite detection in urine depends on the pattern of use, i.e. occasional vs. frequent.  Cannabinoids are often cited as being detected in urine for up to 30 days after stopping use.  Oral Fluid THC screens primarily for the presence of parent drug and is detected for up to 24 hours after use.

The Role of Confirmation Testing

Urine drug screening is an effective tool to rule out the presence of drugs in the donor’s sample.  Drug screening technology provides a reliable, rapid and inexpensive means of ruling out drug abuse.

The most common drug screens are immunoassays.  Immunoassays employ a concept that is similar to a vaccination.  The test drug is an “antigen”, in this scenario it is similar to a virus.  The test reagent includes an “antibody”, this is similar to the antibodies produced by our body when injected with an antiviral vaccine.  If drug is present in the sample, it reacts with the antibody.  This reaction is measured and reported as a positive drug screen.

The reliability of a urine drug screen is at least 97%.   One factor that may cause a “false” positive result includes “look alike” drugs.  The amphetamines are the class of compounds that are most at risk for this issue.

The immunoassay used by Ammon Analytical Laboratory detects amphetamine, methamphetamine and MDMA (“Ecstasy”).  High amounts of chemically similar compounds may cross-react and cause a positive Amphetamines assay. Amphetamine-like drugs include ephedrine, pseudoephedrine, and phenylpropanolamine (PPA).  Confirmation testing rules out “false” positives.

The role of confirmation testing is to provide an alternate scientific method that positively identifies the drug(s).  The most common confirmation method is GC-MS (gas chromatography-mass spectrometry).  GC-MS provides a positive identification of the drug; it gives information about the drug’s chemical structure.  The reliability of GC-MS is at least 99%. GC-MS identification is analogous to a “fingerprint” of the drug’s chemical structure.

Some drug screens detect a class of compounds, such as, opiates, benzodiazepines, and barbiturates. There are as many as six or more compounds in each of the noted drug classes.  Many donors provide a prescription when confronted by a positive drug screen result.

 “The positive Benzodiazepines screen was due to the Klonopin I take.”

When GC-MS was performed, it was learned that the result was actually due to Xanax.  The strength of GC-MS includes the ability to identify the different substances that make up a drug class.  Similar scenarios can be imagined for the other classes of compounds.

When the consequences of a positive drug screen are severe, such as incarceration or child welfare issues,  confirmation testing must be considered.  The positive result must be as reliable as possible, i.e. beyond a shadow of a doubt.

If you have any further questions or need to discuss how to request a confirmation test, please contact one of Ammon Analytical’s professional staff at 866-857-8378.

Post Written by: Jerry Meenan

Reliability of Point of Collection (POC) Testing

iCup Drug Test Kit

     Point of Collection (POC) testing devices are a rapid and reliable means of testing for drugs of abuse in a variety of circumstances.  POC devices, such as the iCup, provide quick screening results that identify presumptive positive results.

Presumptive positive results should be confirmed by an alternative scientific method, e.g. gas chromatography/mass spectrometry (GC/MS).  In our laboratory we offer GC/MS confirmation of presumptive positive urine results.  Confirmations are done on urine samples tested by POC devices and laboratory based testing.  The results are essentially the same – the majority of specimens confirm positive.  Opiates, cocaine, and marijuana, all confirm and show good agreement between the iCup POC devices and GC/MS.  Amphetamines do not always confirm positive because of the many sympathomimetic-like compounds in the marketplace.  The issue of cross reactivity is a problem whether the screening test is a POC device or laboratory based.

Ammon Analytical Laboratory’s extensive experience with the iCup POC device and GC/MS confirmation demonstrates that the reliability is the same as laboratory based testing.

Post Written by: Jerry Meenan

Cross-reactivity Information for Immunoassay Screening Tests

Immunoassay screening tests provide rapid and reliable results for Urine Drug Tests.  On occasion a positive result is questioned by a client.  Is the positive test a “False Positive” result, i.e. caused by a substance other than the intended drug for the assay.  On the other hand, the patient may be taking a drug that is not readily identified as a member of a Drug Class.  The following table summarizes the immunoassays that are performed at Ammon Analytical laboratory and their respective cross-reactivity information.

Cross-reactivity information PDF:    Cross Reactivity

  

Post Written by: Jerry Meenan