Why is nail testing useful in supporting hair strand testing?
Nails are a useful tool in understanding drug and alcohol test results in situations where the sample for the hair strand test is compromised, unsuitable or does not fulfil testing requirements. This is useful when:
- The client has insufficient scalp hair
- The client has little or no body hair
- The client’s hair has been heavily treated or dyed or is compromised in some other way
- The client is not prepared to provide scalp hair
FTS collect nails (as well as body hair) as part of a hair strand sample collection. These samples are stored in case they are required in order to support the overall drug and alcohol investigation.
How does nail testing work?
Both finger and toe nails provide a useful insight in to drug and alcohol usage, and they can play a critical role in supporting the hair test in each case, and if necessary can be used in isolation.
Hair and nails are made from the same substance – keratin. However, unlike hair, nails are constantly fed by the blood, via the root and the nail bed, providing a good overview of historic use.
Cross Section of a Nail
In hair, the levels of drug can fluctuate due to natural hair colour. This is due to differing levels of melanin in the hair that binds with the drug(s), subsequently resulting in different levels. In isolation thisich can be misleading. Nails are not affected by this issue, and so, results of a nail test, used in conjunction with hair strand analysis can provide greater clarity and confidence in the overall findings.
Timeframes in nail testing
Although nails cannot be segmented by month, they can provide results around the following timeframes:-
Identification of drugs around 1-3 weeks after use
Finger nails provide a history of between 3 and 10 months
Toe nails provide a history of between 4 and 12 months
This is because finger and toe nails grow at different rates. In cases where nail clippings are taken from multiple fingers/toes, only a couple of weeks growth is required to provide an assessment on the average pattern of substance misuse during the 4 to 6 months prior to sample.
Drug testing in nails
FTS can detect the same drugs in a nail samples, as a hair strand sample. This means that up to 37 different drugs can be detected.
Alcohol testing in nails
Testing for alcohol in nails is done by identifying the marker ethyl glucuronide (EtG). Care is taken to ensure that the client has not been working with chemicals or substances containing alcohol before the test is performed. In these instances, toe nails often provide a viable alternative.