FAQs

Your questions about drug and alcohol testing, answered.

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Hair Testing

How does hair testing work?

On consuming alcohol and certain drugs, the body breaks down the substances into metabolites. Drugs and metabolites circulate in the bloodstream and are then transferred into hair fibres on the scalp and elsewhere. Each drug detected in the hair has its own chemical ‘fingerprint’. When tested by a laboratory, the presence of a metabolite in a hair sample indicates if and when a person has ingested the substance over a period.

Hair on the human scalp typically grows one centimetre each month. A three-centimetre strand of hair can therefore be tested to accurately reflect drug and alcohol use over approximately three months.

At the laboratory, this sample is cut into sections of one centimetre length and each is tested via via LC-MS/MS, or Liquid Chromatography–Mass Spectrometry. When analysed by an expert, the test results can prove substance use across a 12-month period, approximately. In the past, the technique has been used to gauge cocaine and heroin use after 24 months.

What substances can hair testing detect?

Hair test can reliably detect the use of alcohol and virtually all drugs – provided the drug has been tested for in the past. For a full list of the drug substances we test for, click here.

How are hair samples collected?

A lock of hair approximately 3mm long is needed for hair testing, usually cut from the head. This sample should be placed in a special foil wrap, inside a sealed, tamper-proof envelope that is sent to the laboratory.

Can anybody take a hair sample?

In short, yes. The collector must be able to guarantee the integrity of the sample to generate an accurate test result, however. For this reason, relatives or friends of a donor should not be employed as collectors. A GP, solicitor or other professional is acceptable. We recommend a trained collector is employed to take the sample.

For all collections by untrained collectors, the hair testing laboratory should provide instructions with detailed schematic drawings.

At Cansford, we provide our own expert collectors at 48 hours notice, anywhere in the UK. Each collector is trained to put donors at ease and make the collection process as comfortable as possible. For more information on our collectors, click here.

Can bald people be hair-tested?

Yes – providing they have body hair. If the donor has no hair on their head, their chest, underarm or pubic hair can be tested instead. This may affect the detection timeframe for the sample, however.

In cases where donors have no body hair, it’s possible to test their fingernails or toenails for traces of drugs and alcohol, between 3 and 6 months after the substance was used.

How long must hair be to be tested?

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Is it possible to test for substances week by week?

Yes; some laboratories – including Cansford Laboratories – will conduct hair tests on three millimetre-long hair samples when an allegation of specific substance abuse is made – for example, if a donor had their drink tampered with. In this case, the test result will show a spike in concentration of the substance.

Testing a three millimetre section of a hair sample is not accurate enough to indicate substance use on an exact date, but is useful to indicate an exceptional instance within a pattern of drug use.

Can a hair test categorically prove that a donor has stopped using a substance?

Immediately after they’ve stopped using a substance, a heavy drug or alcohol user will still present 10–20% of their previous level of that substance in their sample. This is because it takes three to four months for traces of a substance to disappear from new hair.

As such, it may be necessary to retest a donor after three to four months to prove they have finished using a substance altogether.

A 2 ng/mg trace of MDMA has been found in a hair sample. How much of the substance did the donor take?

Making an accurate judgement of this kind is not possible for two reasons. Different people take up substances at different rates, so each person acts as their own control. Furthermore, the purity of a drug ingested affects the amount present in a donor’s sample. Therefore, no single standard of substance concentration exists.

Two donors claim to have used the same amount of drugs, but the results from their hair tests are very different. Is one lying?

It’s possible both donors are telling the truth because metabolites pass into hair fibres at different rates. If one parent was fair-haired and the other dark, a toxicologist would expect to find higher substance levels in the darker hair sample. Other variables affect uptake and would be considered by the laboratory conducting the test.

If both donors claimed to be taking similar amounts of drug at the same time but the test results demonstrated different patterns of use, it’s reasonable to ascertain that one or both of the donors is lying.

Blood Testing

How does blood testing work?

‘PEth’ blood tests like those provided by Cansford Laboratories are typically used to complement other test methods – especially hair tests. Unlike hair tests, blood tests can indicate changes in the amount of substance used by the donor, but within a shorter time window of up to 4 weeks.

What substances can blood tests detect?

Blood tests as offered by Cansford Laboratories are used to detect alcohol use

Over what time period can blood test detect drug or alcohol use?

Blood tests have a shorter time window than hair testing – detecting substance use up to 4 weeks after the incident.

How are blood samples collected?

Blood samples are collected by a phlebotomist – a specialist collector – using a needle.

Oral Fluid (Saliva) Testing

How does oral fluid (saliva) testing work?

Oral fluid, or saliva, testing can be used for both screening and confirmation testing for drugs and alcohol.

A test could begin with an immunoassay screening – a simple process through which results can be delivered in the field. Positive results may then be confirmed using a laboratory test, such as Liquid Chromatography with Mass Spectrometry – the rapid, sensitive method used at Cansford Laboratories.

As oral fluid testing only offers results across a limited detection window, the method is most commonly used as an initial or supporting test. Applications can include:

  • Random drug screening;
  • Day-to-day testing of subjects under intense supervision, and;
  • Providing complementary evidence for hair tests, in order to provide proof of both short and long-term consumption.

We favour oral fluid testing over urine testing in all of the situations above. Unlike urine testing, collection of oral fluid samples can be easily supervised, offering less opportunity for donors to contaminate or tamper with their sample.

What substances can oral fluid tests detect?

Oral fluid tests can detect alcohol and a range of drug substances. For more information, click here.

Over what time period can blood test detect drug or alcohol use?

Blood tests have a shorter time window than hair testing – detecting substance use up to 4 weeks after the incident.

How are oral fluid samples collected?

For both point-of-care and laboratory tests, samples are collected by pressing a swab into the donor’s inner cheek – a non-invasive procedure which can be supervised, unlike urine testing.

Nail Testing

How does nail testing work?

When ingested, different substances produce different metabolites – or chemical markers – inside our bodies. These metabolites become incorporated in nail tissue via the nail matrix and nail bed.

While the detection window for nail tests varies according to the length of the nail, nail tests are a useful alternative for historical drug and alcohol testing when hair testing is not possible – including when the donor’s hair is too short or has been cosmetically treated.

What substances can nail tests detect?

Nail tests can be used to detect alcohol use and various drugs. For more information, click here.

How are nail samples collected?

For both point-of-care and laboratory tests, samples are collected by pressing a swab into the donor’s inner cheek – a non-invasive procedure which can be supervised, unlike urine testing.

DNA Testing

What can DNA tests detect?

DNA tests are used to confirm the relationship of one donor to another. In most instances, DNA tests are used to confirm whether donor is the father of another. DNA tests may also be used to prove maternity and sibling relationships.

How are DNA samples collected?

For both point-of-care and laboratory tests, samples are collected by pressing a swab into the donor’s inner cheek – a non-invasive procedure which can be supervised, unlike urine testing.

Costs

How much do drug and alcohol tests cost?

The cost of a drug test can vary according to a number of factors, including the type of test, the number of drugs tested for and the time-frame of drug intake under assessment.

Our laboratory team is on hand to help provide the right test for your circumstances. For more information, call us on +44 (0)29 2068 2031.

Turnaround Times

What are the turnaround times for the tests we offer?

Cansford Laboratories is proud to offer the UK’s fastest drug and alcohol laboratory testing service.

Our collections team are typically available within 48 hours’, Monday to Friday.

Point-of-care oral fluid tests are generated less than five minutes after the test, on site.

Turnaround times for our laboratory test results are as follows:

 

Laboratory test typeTypical turnaround (from receipt of sample to delivery of results)Average turnaround time for UK laboratories
Hair test (drug & alcohol)5–10 days
Blood test (alcohol)
Oral fluid test (drug & alcohol)24 hours3 days
Nail test (drug & alcohol)48 hours5–10 days
DNA test

Using results in court

Which types of test result are admissible in court?

All test results supplied by Cansford Laboratories are admissible in court, providing that the chain of custody for the sample is unbroken.

This means that the sample is provided by the correct person, and the sample is not tampered with before being sent to our lab. The chain of custody can be guaranteed by working with one of our UK-wide collection team. Alternatively, witnesses to the collection process can testify in writing that the chain of custody was not broken.

Scientific terminology, explained

Cut-offs

A cut-off is a value which drug test results are compared against. If results are below the cut-off, they are considered as ‘not Detected’ or ‘negative’. Results above the cut-off are considered ‘detected’ or ‘positive’.Typically, there are two types of drug cut-offs; the ‘analytical’ cut-off and the ‘user’ cut-off. The analytical cut-off is based on the limit of the testing method used to test the sample. When a positive result gives a reading significantly above this analytical cut-off, we can confidently conclude that drug usage has taken place within the timeframe covered by the sample.

Detection window

The length of time that a substance can be detected by a test method, after the donor is exposed to the substance. For example, hair testing can detect drug or alcohol usage up to 6 months after use.

Immunoassay

Immunoassay tests are used by laboratories to screen for ‘negative’ or ‘presumptive positive’ samples. They deliver rapid results – often at the point of testing – but ‘presumed positive’ results should be confirmed by a more accurate laboratory test process, such Gas Chromatography or Liquid Chromatography with Mass Spectrometry (the latter which we use at Cansford Laboratories).

LC-MS/MS

LC-MS/MS refers to Liquid Chromatography with Mass Spectrometry. This is the laboratory technique we use to test hair, nail and oral fluid samples.LC-MS/MS confirms the presence of specific substances in samples with exceptional sensitivity. Expert analysis is necessary to ensure accurate test results.

Metabolite

In the context of drug and alcohol testing, a metabolite is a chemical created as a result of drugs or alcohol having been metabolised – or broken down – inside the body. Different substances produce different metabolites. Hair, nail and oral fluid samples can therefore be tested for the presence of specific substances according to metabolites in their body that indicate whether the donor ingested the relevant substance.

Oral fluid

‘Oral fluid’ is saliva.

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