Has this person used Cocaine in the past 3 months?

This section is about testing for Cocaine use

Others say he has used Cocaine in the last 3 months, we say he hasn’t.

Obtaining reliable evidence from Drug and Alcohol tests in care proceedings is a complex issue.

Test results should not be taken at face value or they can be very misleading unless:

• The correct test profile is applied to each case.
• The results are considered in context of all influencing factors.
• Experts with the necessary skills and experience in the application of testing in child care proceedings investigate these factors and the test data thoroughly.
• The expert is willing to produce an opinion based on the balance of probabilities as to whether drugs and/or alcohol could be a factor in the parent’s ability to provide a safe environment for the child.

The following case history demonstrates that drug testing does not always find the right answer to the important question; whether drugs are a factor in the case. They show that when the incorrect test profile is used and an interpretation of the results is made simply on whether drugs are above or below a defined cut-off in the hair sample tested, then frequently the wrong conclusions are made and consequently the court can often be misled.

Instruction: Provide an overview for the last 3 months to establish if the client was using Cocaine.

An alternative laboratory carried out a simple standard test with no additional detailed investigation

A hair sample was collected at the end of May to carry out a test for cocaine to cover a 3-month history. The hair sample was cut to a single section of 3cm in length (un-segmented). No client interview conducted.

Alternative laboratory results

Cocaine and one metabolite above cut-off, interpreted as Positive and the laboratory concluded:

“The levels observed in the 0-90 day segment indicate that the donor consumed cocaine on multiple occasions within the time period tested.”

FTS comment

The hair was not segmented providing a “blunt instrument” to assess the pattern of drug use, which provided a misleading conclusion. All parties and the court therefore understandably assumed that the client had been using cocaine during the approximate 3- month period, from March to May. This result was to be the determining factor in the decision-making process with regards to the child’s residence.

FTS Investigation: Thorough investigation and comprehensive test profile.

Establishing key facts with our detailed client questionnaire

The 25 minute client interview established in summary:

• The client had previously used cocaine on a frequent basis but claimed to have stopped using just over 3 months prior to testing. No hair cosmetics or scalp medications had been used that could influence drug levels in hair.
• The matched hair sample and also a urine sample were tested by FTS, who carried out a hair strand test and urine test for cocaine to establish a 3 month history up to immediately prior to sampling.

Hair sample cut to 4cm and segmented into 4 x 1cm segments

FTS completed the testing and investigated all factors that could influence the outcome and interpretation of the test results. The profile of very high levels in hair section 4 reducing significantly and progressively in each section to very low levels in hair section 1, combined with a negative urine test, clearly represented carry-over of cocaine in the dormant hair from previous use. FTS used their experience referencing their unique and comprehensive database to produce a report with a clear and unambiguous conclusion on the client’s pattern of drug use, based on the balance of probabilities.

FTS laboratory results

FTS experts reveal a Negative result over the same period and concluded on a balance of probabilities:

“These results are compatible with the client using cocaine on a frequent basis up to around February. Cocaine use appears to have stopped sometime during February or possibly early March and there does not appear to have been any active cocaine use for the subsequent period of approximately 3 months up to the point of sample collection at the end of May. These results appear to be consistent with the clients’ declaration.”

Concluding Comments

When the appropriate test profile is used and results interpreted in context with key factors (in particular, previous very frequent use) and referenced against our unique database, FTS can provide the most probable and reliable conclusion.

This conclusion is often different from other laboratories, despite both laboratories finding similar average levels in the hair, which highlights the serious implications of using an inappropriate test profile and taking results at face value. The different conclusion in this case would probably lead to a different decision being made with regards to the child’s residence. In certain cases, given the client has honestly declared previous use and has shown motivation to stop using, then these results may provide justification for the cost of additional testing to ensure abstinence from drug use is maintained, which means decisions can be made with more confidence.