Hair drug testing vs nail drug testing

In this article, we take a closer look at hair drug testing and nail drug testing, how each test works, and the benefits of each test.

How can drugs be detected in hair and nails?

When a person consumes drugs, they are broken down by the liver and a proportion of the parent drug and its metabolites are released into the bloodstream, with a small amount being excreted by the body in a variety of ways.

Whereas urine and oral fluid (saliva) drug testing methods provide us with a ‘narrow-window’ of detection for drug use (from a few hours up to a few days), hair drug tests and nail drug tests offer what is known as a ‘wide-window’ of detection (up to 12 months).

This is due to the way in which drugs are retained in the hair and nails long after substances were first consumed.

In hair, a proportion of the parent drug and its metabolites finds its way into the hair follicle, becoming trapped in the medulla – the innermost layer of the hair shaft – and remains in the hair as it grows.

A hair drug test can provide an insight into historic drug use for up to 12 months after drugs were first consumed (depending on the length of hair available).

In nails, a proportion of the parent drug and its metabolites finds its way to the nail bed, becoming trapped in the keratin fibres along the entire length of the nail.

A nail drug test can also provide an insight into drug use for the period prior to samples being collected (overview of up to 12 months).

What is hair drug testing?

A hair drug test, also known as a hair strand test or a hair follicle test, involves analysing samples of head hair or body hair for the presence of drugs and their metabolites.

When a person consumes drugs, they are passed into the bloodstream, and the parent drug and a proportion of the drug’s metabolites enter the hair follicle.

When the hair is subjected to analysis at the toxicology laboratory the parent drug and its metabolites can be identified within the hair.

How does hair drug testing work?

Hair drug testing works by analysing a cut hair sample for the presence of drugs and their metabolites.

When a person consumes drugs, they are broken down by the liver, and a proportion of the parent drug and its metabolites are absorbed into the bloodstream.

These drugs then enter the hair follicle and become trapped in the medulla, the innermost layer of the hair shaft, making it possible to detect them during analysis at the toxicology laboratory.

It takes approximately 7-10 days for the hair containing the drugs to grow above the surface of the scalp, and two weeks for this hair to be included in a cut sample.

What are the different types of hair drug testing?

There are two methods of analysis available for head hair drug testing: segmented or overview analysis.

The rate at which head hair grows enables us to determine a pattern of drug use over a defined period, for a month-by-month profile, depending on the length of hair selected (1cm of hair = one month of growth). This is known as segmented analysis and is the most detailed form of hair strand testing for drugs.

Overview analysis provides a more general insight into a person’s drug use. This is because any episodes of drug use are averaged out over the period being tested.

The maximum length of head hair that can be tested to provide an overview of drug use is 3cms, which provides an overview of three months. An overview of 12 months can also be provided but would be reported as 4 x 3-month overviews (4 x 3cms), rather than one 12-month overview.

Can you test for drugs in body hair?

If head hair is not available for drug testing, a sample of body hair can be collected instead, from the chest, leg, arm, back or underarm.

However, unlike head hair, body hair cannot be segmented to provide a month-by-month profile.

This is because the growth rate of body hair differs from head hair and is not consistent, meaning that a sample of body hair can only be used to provide up to a 12-month overview of drug use.

Unlike head hair, body hair samples are collected by weight, rather than the length of the hair strand.

Beard hair can also be used and can go beyond 12 months of drug use depending on the length of hair available.

Unlike other types of body hair, beard hair is also collected by length rather than by weight.

What is nail drug testing?

Nail drug testing is an extremely reliable and effective method for identifying historic drug use.

Similar to what we see in hair, when a person consumes drugs, a proportion of the parent drug and its metabolites finds its way to the nail bed, becoming trapped in the keratin fibres along the entire length of the nail.

Either fingernail clippings or toenail clippings can be used for nail drug testing, however the two sample types cannot be mixed at the laboratory. This is because fingernails and toenails grow at different rates, with each offering differing insight into drug use – an overview of up to six months for fingernails, and an overview of up to 12 months for toenails.

Unlike head hair, which can be segmented to provide a month-by-month insight into drug use (depending on the length of hair available), nail clippings cannot be segmented. This means that only an overview of drug use can be provided for the period prior to samples being collected (up to 12 months).

Any artificial nail applications including acrylics, gels, polish, and nail extensions must also be completely removed prior to testing, so as not to impact the results.

How does a nail drug test work?

When a person consumes drugs, they are broken down by the liver and a proportion of the parent drug and its metabolites are released into the bloodstream.

These metabolites then pass to the blood vessels below the nail and into the nails themselves.

Nails are made from keratin, which is a fibrous protein. Substances become trapped in the keratin fibres of the nail and can be identified via laboratory testing.

How are hair and nail samples collected for testing?

Hair samples

When collecting a sample of head hair for a hair strand test for drugs, the site of sample collection will depend on the length of hair required for analysis, according to the period for which we have been instructed to test.

For example, a longer section of hair would be required for a 12-month analysis than for a three-month analysis.

Around 200 individual strands of head hair (about the width of a pencil) need to be cut from the root, as close to the scalp as possible, with two samples usually being taken – an A sample and a B sample. This may leave two small bald patches, but every effort will be made to ensure that these are as unobtrusive as possible.

The sample collector will always assess the most suitable sample site, based on the testing requirements. This is usually the rear of the head in line with the top of the ears.  However, the sample collector will always discuss this with the sample donor and, if possible, change the sample site to accommodate the sample donor’s request, provided the required sample length can still be obtained.

If head hair is not available for testing, body hair can be collected from the chest, leg, arm, back, or underarm. However, unlike head hair, body hair cannot be segmented to provide a month-by-month profile.

This is because the growth rate of body hair differs from head hair and is not consistent, meaning that a sample of body hair can only be used to provide up to a 12-month overview of drug use.

Beard hair can also be used, and can provide a detection window beyond 12 months, depending on the length of hair available.

Nail samples

When collecting a sample of nail clippings for a nail drug test, the nail is clipped from as close to the nail bed as possible.

If the nail is long (5mm or above), then only one clipping is required. If the nails are short, a few nail clippings may be collected.

Either fingernail clippings or toenail clippings can be used for the test, but not a mixture of both. This is because fingernails and toenails grow at different rates, with fingernails providing an overview of up to six months for drug use, and toenails providing an overview of up to 12 months.

For nail clipping sample collections, all nail polish or artificial nail applications including nail varnish, gel polish and acrylics must be completely removed prior to the collection appointment.

Which drug testing method is best? Hair drug testing or nail drug testing?

Both hair drug testing and nail drug testing can provide an extremely valuable insight into a person’s historic drug use.

However, which method you choose will depend on your client’s circumstances, and the requirements of the court.

To identify trends in drug use, such as an increase or decrease over time, or to highlight intermittent use, segmented analysis using head hair is highly recommended.

Overview analysis using hair or nails is useful if you require a more general insight into a person’s drug use over a certain period (up to 12 months).

Where can I get a hair drug test or a nail drug test?

AlphaBiolabs has extensive experience providing drug testing services for local authorities, family law professionals and social workers.

We have invested in the very latest technology for our state-of-the-art toxicology laboratory, employing top scientists, so you can be confident of receiving a 100 per cent accurate result.

Our network of professional sample collectors are trained to collect a variety of samples under chain of custody, including hair and nail samples for drug testing, and our test results are accepted by public bodies and government agencies, including Family Court.

We also offer free sample collection for legally-instructed drug tests at our Dublin walk-in centre.

For expert advice on which test is best for your client, or to request a quote for drug testing, call our Customer Services team on 01 402 9466 or email testing@alphabiolabs.com.