Strategy (Drugs)

General Test Principles

In general, drug testing involves two stages. In the first stage, the samples are screened for drug groups (usually by immunoassay). If the result of this screening is negative (see cutoffs explanation below) then the sample is considered negative for that particular drug group and no further work is carried out. If however the results of the screening test are positive, then the sample is forwarded for more specific confirmation testing. It is only if the results are positive at this stage that a positive report can be issued.

Samples for Drugs of Abuse Testing

<For alcohol testing details click here>

Blood, urine, hair and oral fluid (saliva) can all contain traces of drugs; therefore analysis of each of these sample types can provide useful information – the choice of which sample to use will depend upon particular need.

Urine

A popular choice for routine drug screening in the workplace. It can be collected relatively easily, particularly if carried out as part of a general medical examination. It gives a satisfactory detection window on drug use (particularly for cannabis), and therefore is often the sample of choice for pre-employment drug screening. Collected samples can be easily dispatched to the laboratory where full laboratory analysis takes place.

Urine is useful for:

  • Routine pre-employment testing (often with medical)
  • Unannounced testing for lifestyle

Collected urine samples can also be screened on-site using a point-of-care device and presumptive results can be obtained within a few minutes. Suspected positive samples can be sent to the laboratory for legally defensible confirmation analysis. This approach is particularly useful if fast on-site identification of negative sample is needed – for example in for-cause testing.

Urine Detection Window: up to 5 days

Urine Advantages:

  • Well-established & accepted
  • Plenty of sample, provision of duplicate
  • Detection times up to 5 days (‘lifestyle’ detection)
  • Good for alcohol detection/confirmation

Urine Disadavantages:

  • ‘Shy’ bladder or delays possible
  • Adulteration/substitution potential (unobserved provision)
  • Embarrassing sample provision
  • Toilet needed
  • Poor correlation with impairment (detected long after psychoactive effect)

Oral Fluid (Saliva)

Evolving as a popular and successful testing matrix. It provides shorter detection windows than urine but is much less invasive. Collected samples are generally screened on-site (Drager 5000 testing device or Oratect). Suspected positive samples can be confirmed by laboratory analysis of urine or another oral fluid sample.

Oral Fluid is often useful for:

  • For-cause testing
  • Unannounced testing

The Drager 5000 is a high quality portable, electronic testing device, which removes any subjective operator assessment of the test results. Oral fluid testing has many advantages:

Oral Fluid Detection Window: up to 2 days

Oral Fluid Advantages:

  • High correlation with impairment
  • Non-invasive. High acceptance by donors
  • Easy collection by non-medical staff
  • No toilet needed
  • Detection times up to 2 days (‘Impairment’ detection)
  • Adulteration possibility low

Oral Fluid Disadavantages:

  • Short detection time if ‘lifestyle’ detection required.
  • Not preferred for alcohol measurement


Hair testing

Comparatively more expensive than saliva or urine but provides much longer detection windows (up to several months or more). Therefore it is generally used to confirm abstinence for individuals undergoing counselling and treatment or to provide lifestyle information on certain job applicants.

Hair is useful for:

  • Demonstration of long term abstinence
  • Treatment support
  • Lifestyle assessment

Hair can also be used for assessment of long-term alcohol misuse <link to hair testing for alcohol>.

Oral Fluid Detection Window: 2 weeks to 3 months +

Hair Advantages:

  • Retrospective drug detection
  • Sensitive
  • Detection times up to 3 months or days (‘Lifestyle’ detection)
  • Adulteration possibility low

Hair Disadavantages:

  • No correlation with impairment
  • Relatively expensive
  • Professional collection advised.

Drug Panels (which drugs are covered?)

The standard drug panel represents a broad range of commonly abused drugs:

  • Amphetamine
  • Methylamphetamine
  • Ecstasy drugs (eg MDMA)
  • Opiates (morphine/heroin, codeine, dihydrocodeine)
  • Cannabis
  • Benzodiazepines (eg diazepam, temazepam)
  • Cocaine

Additional drugs can also be added if required.

 

Cutoffs

Cutoffs are defined concentrations used to determine if a sample is to be considered positive or negative for drugs. These cutoff values have been determined within the international workplace drug testing industry and the application of these values follows best practice.  Cutoffs apply to both screening and confirmatory testing stages. Some examples:

  • If a sample is analysed and the value obtained falls below the defined cutoff (either screening or confirmation), then the sample is considered negative for drugs. A negative report is issued.
  • If a sample is analysed and found to give a positive result (ie above the cutoff) at the screening stage, it is then forwarded to the confirmation stage. If this analysis then shows a particular drug to be present above the cutoff, it is considered positive for that drug. The positive laboratory report is then forwarded for medical review.

 

NIVHA provides a complete service from sample collection, on-site presumptive testing, laboratory analysis and reporting.

All analytical work is accredited to UKAS 17025 standard. Our practice adheres to European guidelines for workplace drug testing (www.ewdts.org).

Client-Enabled Testing

NIVHA can provide customers with the necessary tools, training and support to carry out their own drug testing in-house. The success of modern oral fluid screening technology has now made this possible.

This approach can be a particularly cost-effective.

Please contact us if you would like to learn more about this exciting approach to testing.

 

 

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