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Timeframes: Hair vs. Urine Testing

We are often asked about the different time periods covered by hair drug testing and urine drug testing, in this blog we hope to clarify the difference between the two so that you can be sure that you are choosing the most suitable method of testing for your case.

Hair Testing

When collecting a hair sample, the two weeks prior to the collection date of the hair will not be included in the time period associated with the sample. This is due to the fact that it takes approximately two weeks before hair has grown to a sufficient length above the scalp in order to be collected. Every centimetre of hair collected covers approximately a one month time period, meaning that hair testing for drugs can cover many months or even years depending on the length of the hair.

Urine Testing

In comparison, the time period covered by a urine test consists of a much smaller window, typically a few days prior to the urine collection date. It is therefore recommended that urine tests are carried out regularly i.e. every two days. If urine testing is not carried out regularly, then it is possible for drug use to go undetected. In addition, if the urine test conducted is announced to the donor and not undertaken at random it is also possible for a donor to actively abstain from drug use for the few days prior to the urine sample collection.

Can you compare the results?

Due to the fact that urine and hair analysis are undertaken on different matrices, using different techniques, with different cut-off levels and have different windows of detection, the results obtained should not be directly compared.

It is possible for a donor to provide a ‘detected’ hair test result and a ‘negative’ urine test result if they have abstained from drug use for the few days prior to the urine sample being collected but have used drugs throughout the rest of the time period covered by the hair sample.

Lextox Hair Drug Testing

Our expertise is in the analysis of hair samples for evidence of drugs and metabolites and the interpretation of these results. At Lextox we undertake hair testing for 90 drugs and metabolites including psychoactive substances, spice and anti-epileptics (pregabalin and gabapentin). Hair sample collections can be arranged immediately with collection usually taking place within 48 hours. Analysis Results and Expert Reports are issued within an average of 4 working days.

To book your hair sample collection appointment, call 029 2048 4141 or email [email protected] to speak to your dedicated client support team.

Published 18/01/18 – All information correct at time of publication