Why drug and alcohol testing costs more than it should – a solution

Tyson Thomas

Tyson Thomas

on Jan 24, 2023

Thousands of drug and alcohol tests are ordered by family courts in the UK every year to assess drug or alcohol misuse, especially where there is a child at risk. Legal experts can’t be expected to stay abreast of developments in testing methods, the latest thinking, or the pros and cons of one type of test versus another. Here, Tyson Thomas, Cansford's Reporting Scientist, outlines what you need to know to help you and your practice*. 

 Stress, stress and more stress (not to mention expensive)

As such, we are seeing unnecessary duplication of tests or additional tests being ordered to assess or monitor alcohol abuse: tests that are not only expensive to conduct - a pressure that often falls on the public purse - but are also stressful for the donor to undergo. We are also seeing inconsistencies between testing labs, with some recommending more tests than we believe are necessary.

Therefore, I believe alcohol testing is costing more than it should, but what can be done about it? This article aims to help those ordering tests to understand different test types and approaches; look at options for streamlining testing to reduce cost while maintaining accuracy of results; and avoid unnecessary stress for donors. 

Drug and alcohol testing: what are the options?

Carbohydrate-deficient transferrin (CDT) tests

There are several blood tests commonly used to assess alcohol misuse. Carbohydrate-deficient transferrin (CDT) tests are one of the most used biomarkers for monitoring alcohol use. CDT is very commonly court-ordered in the UK through family courts, although it does have some limitations. 

The first is that elevated CDT levels are not always caused by alcohol abuse. Misleading false positive results for CDT testing are seen in many cases, and CDT can be affected by factors such as hormonal changes as well as other diseases and deficiencies. In addition, a false negative CDT test result is sometimes seen in females, and further studies are needed to explain the relation of gender to the sensitivity of the test.

Liver flow tests

Liver flow tests (LF/LFTs) are a group of blood tests that provide information about the state of a donor’s liver. The biomarker, the Gamma Glutamyl Transferase (GGT) can be an indicator of a person’s alcohol use. Here too, however, there are some limitations.

The results may be normal in patients who suffer from serious liver disease and abnormal in patients with no liver disease, or other diseases that may interfere with results. Certain medication can also increase GGT levels, and there have been numerous cases where heavy alcohol users display normal LFT readings.

 Full blood count tests

Full Blood Count tests (MVC) are less commonly court ordered but do turn up from time to time. The MCV test is a part of a full blood count (FBC) and is mainly used to identify recently ingested alcohol. This test looks at the average volume of red blood cells in the blood sample and can provide some indication of possible alcohol abuse.

This is the least accurate of all blood testing methods, with a sensitivity rate of 44%, and people may have MCV readings outside the normal range for a variety of reasons, such as vitamin deficiencies, medication, and previous alcohol consumption. It has also been known for heavy alcohol consumers to have normal MCV readings, and people who have not consumed alcohol to have abnormal readings.

 Phosphatidylethanol testing

Phosphatidylethanol (PEth) testing is a direct biomarker of alcohol consumption. PEth is only detected when alcohol has been consumed, and correlates directly with the amount consumed.

PEth provides the highest sensitivity for the detection of current regular alcohol consumption, and a single test shows levels of consumption for (up to) the previous 28 days. Regular PEth testing can therefore easily be used to monitor alcohol abuse cases over several months.

Unlike CDT testing, which will only show ‘chronic’ or ‘not chronic’ use, PEth offers three cut off points, allowing for the results to show abstinence or low alcohol consumption; alcohol consumption; or chronic consumption. Still a relatively new form of test, acceptance is starting to gain momentum, and tens of thousands of samples have been tested with no known issues identified.

Dry blood spot (DBS) test

PEth can be collected as a dry blood spot (DBS) test, which requires a small blood sample from a finger prick. Dried, the sample is stable for months at ambient temperature. In addition, a DBS test does not require specialist phlebotomy skills; it can be done wherever your clients are – either at home or in another setting.

This form of testing reduces the need for venepuncture, which is helpful for people with poor venous access. It is also easy to store and transport collected samples, as they do not deteriorate quickly in the same way venous blood samples can.

Getting it right matters

The most common court order in alcohol testing is for CDT and LFT tests, sometimes backed up by a hair alcohol test. These two tests could be replaced by a single PEth test but, as the PEth test gains recognition, we are increasingly seeing all three tests being court ordered. This is completely unnecessary, and more than doubles the cost to the public purse. It's a worrying trend.

Some laboratories argue that PEth needs to be substantiated with other blood tests, such as CDT or LTF. We believe this approach to be unnecessary, needlessly expensive, and stressful for the donor.

Combining PEth and hair testing for alcohol misuse - the former covering a 28-day period, the latter up to six months - can show differences and comparisons between recent and long-term alcohol use and can also make a vast different to case outcomes.

Far-reaching implications for children and families

We all know that the accuracy of drug and alcohol testing has far-reaching implications for children and families. Take for example the husband and wife who were applying for custody of their children. Both had hair and PEth samples collected, with the results indicating excessive alcohol consumption. Both parents contested the results and claimed to be abstinent.

PEth analysis was undertaken for a period of six months, showing a decrease in alcohol consumption to the point of abstinence (or irregular low-level consumption) by month four. Further hair samples were collected at the end of the six-month period and analysed over a period of three months.

The results supported the ongoing PEth analysis results. The parents were granted supervised access to the children, prior to being granted full access and the potential return of the children to their care.

Preventing unnecessary expense

 We see countless examples like these, where PEth and hair analysis gives a clear picture of drug or alcohol use over time, and we believe that thousands of pounds could be saved every year by replacing multiple venous blood tests that measure CDT, LTF and FBC with a simple PEth finger prick test.

In my view, this combination offers the best way of demonstrating short- and long-term drug or alcohol use. A PEth test as a monitoring tool, is often conducted monthly over a period of several months. This is particularly effective if your client is keen to demonstrate either a reduction in alcohol use or abstinence, as it can confirm both extremely low usage levels and abstinence.

 We welcome this move and will continue in our bid to raise awareness of the accuracy and cost saving benefits of combined PEth and hair testing.

Do have any questions?

At Cansford labs, our team of advisors is always happy to answer questions and help in any way they can. Please do get in touch - either by phone on 029 2054 0567, by email at or through our live chat here on our main page:

Video credit:  Nicky from Pixabay 

* This article was previously published in Resolution's Magazine October 2022'


Tyson Thomas

Tyson Thomas

Tyson Thomas is a Reporting Scientist at Cansford Laboratories. He provides Expert Reports interpreting hair drug and alcohol test results for use by legal professionals and presents results in court as an Expert Witness. Tyson has an MSc in Analytical and Forensic Science from the University of South Wales.

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