Hair analysis for the MPU: hair length, dyeing and what to watch out for

For a hair analysis for alcohol (EtG), the laboratory evaluates a maximum of 3 cm of hair per analysis, which corresponds to about 3 months. For proof covering 12 months you therefore need several analyses. Dyed, bleached or tinted hair makes the EtG hair analysis unusable – you then have to switch to urine or PEth.

How does hair analysis work for the MPU?

Hair analysis detects use retrospectively over a longer period, because substances are deposited in the hair as it grows. For the MPU (medical-psychological assessment, Medizinisch-Psychologische Untersuchung) it is used both for alcohol (via the marker EtG) and for drugs.

For the analysis to count, it must meet the CTU criteria (chemical-toxicological analysis, Chemisch-Toxikologische Untersuchung). The laboratory must be accredited to DIN EN ISO/IEC 17025, your identity is checked and the sample chain is documented without gaps (chain of custody). The page Proof of abstinence (Abstinenznachweis) shows all the forms of proof available.

How long does your hair need to be for a hair analysis?

In an alcohol hair analysis (EtG), a maximum of 3 cm of hair is evaluated per analysis, which covers about 3 months retrospectively. Greater length therefore does not extend the period covered by a single analysis.

The specific minimum length your laboratory needs for the sample and how the sample is taken are best clarified directly with the laboratory before you start. This way you avoid an appointment being unusable because your hair is too short.

How many hair analyses do you need for 6 or 12 months?

For 12 months of alcohol abstinence you need several hair analyses, because a single analysis only covers about 3 months. The analyses must cover the period without gaps.

The number is a calculated guide based on 3 months per analysis. The exact sampling schedule is set by your laboratory or programme.

Whether 6 or 12 months are required depends on your case. 12 months are common, and in the case of dependence usually at least 12 months. This is stated in the order and in your file.

It is also important that you start early enough. Because the proof must be complete *before* the MPU, the number of analyses required directly determines the earliest date on which you can go for the assessment. If you start late, you push back the whole timetable.

What happens if you dye or bleach your hair?

Dyeing, bleaching, lightening or tinting makes the EtG hair analysis unusable. After such a chemical treatment, the result can no longer be used as proof for alcohol.

For you, this means: as long as you are on a hair programme for alcohol, you should not dye, lighten or tint your hair. If you want to keep dyeing your hair for personal reasons or have already dyed it, hair analysis for alcohol is not an option. There are then two alternatives:

• Urine EtG: unannounced tests, sample usually within about 24 hours, supervised. The usual numbers are 4 tests for 6 months and 6 tests for 12 months.
• PEth in blood: covers roughly the last 2 to 4 weeks and has been recognised since the 4th edition of the assessment criteria (Beurteilungskriterien, 2022). More on this in the guide PEth level explained.

Hair analysis or urine – which suits you better?

Which method suits you better depends on your daily life, your hair and the requirements of your programme. Both routes are recognised if they meet the CTU criteria.

Advantages of hair analysis

Hair analysis covers a longer period with one sample. You do not have to turn up at short notice as often as with urine screening. This can be convenient if you travel a lot for work.

Advantages of urine screening

Urine screening works regardless of hair length and hair treatment. It is therefore the obvious solution if you dye your hair or have very short hair. In return, you must be reachable at all times for a short-notice summons.

How much does a hair analysis for the MPU cost?

As a guide, a hair sample costs about 120 to 200 euros and a urine sample about 60 to 120 euros. Prices vary from provider to provider, so there are only ranges.

The total cost depends mainly on how long your proof has to run and how many samples are needed for it. You can find an overview of all the cost items of an MPU on the page MPU costs.

What do you do with the results?

The results of your hair analyses are your evidence in the MPU procedure and must be available in full. Keep every result in the original and bring all your evidence to the assessment, together with your identity card or passport.

In the psychological interview, the assessor also checks whether your account matches the file, the questionnaire and the lab results. The analyses prove abstinence, but they do not explain what has changed for you. You have to present this yourself in the interview in a way that is understandable.

Which mistakes should you avoid with hair analysis?

The most common mistakes are starting too late, gaps in the evidence period and chemically treated hair. Each of these can cost you months.

• Starting too late: the evidence period is usually the bottleneck of the whole MPU plan.
• Leaving gaps: the analyses must cover the required period continuously.
• Dyeing or bleaching your hair during an alcohol hair programme.
• Choosing a non-accredited laboratory: only proof to DIN EN ISO/IEC 17025 counts.
• Underestimating alcohol: food containing alcohol or mouthwash can also trigger EtG.
• Buying „ready-made“ proof: bought or backdated proof is forgery of documents (Urkundenfälschung).

What you can do now

1. Use file inspection (Akteneinsicht) to clarify whether 6 or 12 months and which substance have to be proven.
2. Choose a method: hair analysis only if you do not dye, bleach or tint your hair – otherwise urine or PEth.
3. Choose an accredited laboratory and ask beforehand whether the assessment centre (Begutachtungsstelle) recognises the programme.
4. Ask for the sampling schedule so that the period is covered without gaps.
5. Alongside abstinence: find suitable preparation.