CellMark Review

When it comes to consumer DNA tests, the market has become pretty saturated in the last ten years, and there’s an overwhelming amount of companies and tests to choose from, all insisting they offer the best service, most accurate results, and so forth. 

People use DNA tests for a myriad of reasons; perhaps to find out meaningful information about their ancestry, their predisposition to certain illnesses, or even the breed of their beloved dog. 

However, DNA can have a life-changing impact when it's being used to prove parentage - for example, in a paternity test - and so it's essential that the company you go with is accurate, efficient, and highly accredited. 

Regardless of whether you’re doing a paternity test for peace of mind or legal reasons, finding a trustworthy company is essential. You may be up against time constraints and financial constrictions, too, but this doesn’t necessarily mean your options have to be limited. 

Today we’ll be reviewing one of the leading DNA Paternity tests on the market: CellMark. We’ll break down everything you need to know about the company, how the test works, and whether it’s worth your time and money, so you can make an informed decision based on trustworthy information. 

About CellMark

CellMark is the pioneer of DNA analysis for paternity testing, and also offers a range of DNA relationship tests, including those for maternity, sibling, avuncular, grandparentage, and Immigration matters too.  

Established in 1987, CellMark has 450+ staff members and is the UK’s most experienced DNA testing service and the world’s first private DNA fingerprinting company. 

It’s one of the largest forensic and DNA testing companies in the world and provides reliable, quality services from a state-of-the-art laboratory in Oxfordshire, UK.

Reasons for Paternity Testing 

A paternity test - or another kind of relationship DNA test - may be required for several reasons.

For example, it may be needed:

  1. to confirm a child’s biological father, for peace of mind
  2. when seeking legal custody of a child 
  3. to amend a child’s birth certificate (ie. change the name, or change the biological father) 
  4. for evidence of paternity when claiming child maintenance

What’s on Offer

Legal Testing 

CellMark’s main DNA testing service is its court-approved paternity test. Their legal DNA paternity test provides a report that is accepted as proof of paternity by courts and government authorities including the CSA. 

It's worth noting that if you intend to use the result of a paternity test in the court of law it must be the right kind of test, and not an unsupervised home paternity test. 

One of the reasons why Cellmark is a popular choice for legal DNA tests is because it's a member of the Ministry of Justice’s accredited bodies, and can therefore carry out paternity tests directed by the civil courts in England and Wales under section 20 of the Family Law Reform Act 1969

This test needs to be organized either through your GP or CellMark’s dedicated sampling service so that the testing process is overseen and conducted by a professional.

This is to ensure the results are not tampered with and that the persons being tested match those in the photographs you'll have to submit (more on this later). 

Peace of Mind Testing 

On the other hand, if you don’t require a test for legal reasons and simply want to do it to satisfy your curiosity and provide peace of mind, CellMark has also introduced a home DNA paternity test, so you can get the same level of accuracy and expertise but from the comfort of your own home. 

These tests are cheaper than the court-approved test and are available to conveniently order online.

Like a legal paternity test, they’re accurate, conclusive, and confidential, but you can’t use them as evidence in a court of law, so be sure what kind of test best suits your circumstances before you order. 

Relationship Testing 

CellMark also offers DNA tests for relationship testing and these can be either legally approved and accredited, or simply performed at home as a peace-of-mind test.

Tests are available for maternity, sibling, grandparentage, and aunts and uncles.

CellMark also offer immigration tests to support an immigration application when proof of a biological relationship is required. These tests are accepted by UK Visas & Immigration. 

So, now onto the test itself. Confused by the scientific jargon? Let's break it down... 

What is DNA?

DNA (Deoxyribonucleic Acid) is the body's genetic 'blueprint’ - it’s what makes you, well, you.

It’s a long thread-like molecule containing your genetic code that determines your characteristics, like eye color, height, or hair color, for example. 

Because we inherit a unique mixture of DNA from our parents, which works out roughly as half from each, no two people have the same genetic code, unless they’re identical twins. 

 However, when this DNA is closely analyzed, those similarities - so the DNA markers we inherited from each of our parents - are the key to unlocking the truth behind our closest relationships. 

How your DNA is Analyzed 

CellMark geneticists analyze up to 24 genetic markers to analyze similarities between the DNA of the alleged father and that of the child. 

The most accurate test can be achieved with the mother’s DNA also sampled, as this way the biological mother’s matching DNA can be excluded from the child's DNA, meaning inherited DNA from the father can be compared alongside the DNA sample from the alleged father. 

Make Sense?

Because of the number of markers analyzed, CellMark paternity tests will either exclude a man as the biological father with 100% certainty or will indicate a high level of confidence that the alleged father is biologically related to the child.  

The results are usually in excess of 99.9999% - which is an extremely high probability when it comes to DNA testing, as no company can guarantee 100% confidence. 

What You Get in Your Kit

If you order a home DNA testing kit, you will receive the kit in a descreet envelope in the post (usually the next day), with the following contents: 

  • A folder with information about Cellmark and the DNA testing kit
  • Clear instructions about how to take the DNA samples
  • A mouth swab for each person to be tested
  • A sample collection card for each person to be tested
  • A sample declaration form for each person, requiring a signature to provide consent
  • A tamperproof, prepaid return envelope

How to Collect Your Samples

You’ll receive instructions with your kit, but roughly the test works in the following way: 

  • Each person providing a sample will first need to complete a declaration form 
  • The name and date of birth of each person will then need to be written on a collection card.
  • Next, a swab should be taken from each person. This is done by swabbing the inside of the mouth to collect cells and DNA. To be sure the DNA is effectively taken, rub the swab on the inside of the cheeks for about ten seconds. 
  • After taking the sample, each person’s swab needs to be placed firmly onto the pink section of their labeled collection card for 5 seconds (you will first need to open the collection card to reveal the pink paper). When the time is up, turn the swab and press again for 5 seconds. The pink paper will turn white where the swab has been pressed and the DNA has been transferred. Then simply close the collection card.
  • Once all of the samples have been collected and pressed onto the necessary collection cards, they can then be placed and sealed in the prepaid tamper-proof envelope, along with the sample declaration forms, and put in the post to return to CellMark.
  • After you’ve submitted your samples, the swabs should be discarded with your normal trash. 

For the Legal Test

For the legal test, things differ slightly. You'll have your samples taken by a professional such as a doctor, nurse, or a Cellmark trained sampler.

The process is just as painless as the home-testing method, requiring a simple cheek swab to be rubbed gently and painlessly on the inside of your mouth to collect the DNA sample. 

You will also need to complete the consent form at the surgery, as well as provide 2 passport-style photographs of each person being tested.

The sample will then be sent to CellMark by the surgery - so you don't need to do anything else at this point. 

Speed of Testing

One of the most attractive aspects of CellMark’s DNA testing service is the efficiency of the service. The company offers a “next day DNA” service for all of its relationship tests, and this comes at no extra cost. 

If your DNA samples arrive at their UK testing laboratory before 10 am, the results will be sent to you, via email, by the end of the next working day, making this test ideal for those who need their result as quickly as possible, particularly for a legal dispute. 

Not only this, but the delivery for your kit is super quick too, meaning the whole process - from ordering your test to receiving your results - should be complete in under a week. 

If you order your home DNA test kit before 3 pm Monday-Friday, you should receive the sampling kit in the post the next day, as CellMark posts out all sampling kits by 1st class Royal Mail post.


Anyone participating in DNA testing is required to know about the Human Tissue Act 2004 before submitting your DNA samples for any kind of testing.

This act requires consent to be taken for every biological sample to be DNA tested, whether it’s used to determine paternity or any other biological relationship. 

This means that written, informed consent must be provided for each adult DNA sample - even those taken from a child. Informed consent means that consent has been submitted knowingly and that the individual hasn’t been subject to any sort of pressure or blackmail. 

CellMark isn’t alone in requiring a consent form, as since 2006 it has been a criminal offense in the UK to submit a biological sample for paternity testing without that person giving their formal consent. 

In the case of a child being tested, anybody in a legal position can give their consent on the child’s behalf, however, it is essential that this person has the legal right to provide consent, ie. they have legal parental responsibility for that child.

Signing on behalf of a child is not only providing consent but acknowledging that you have the legal right to do so on their behalf. 

Cellmark’s testing kit includes consent forms that must be completed by each person submitting a sample. Without the written consent forms the testing process cannot go ahead. 

It’s also important to note that “discreet” DNA testing, ie. when a sample is secretly taken and submitted for testing - is not permitted in the UK.

Safety and Security

Handing over your DNA and data to a company can be a big concern, but Cellmark has taken certain precautions to ensure your sample is as safe as possible in their hands.

All samples are sent to laboratories in specially designed tamper-evident packaging, so it will be obvious if at any point the samples are tampered with. 

Once the testing process is complete and you have received your results, your DNA sample is stored securely by CellMark for 3 months, and will then be destroyed. 

In paternity cases, your identification paperwork is held by the company for one year after testing and is then destroyed in compliance with the Data Protection Act 1998.

Your information will not be passed onto anyone you have not given CellMark the authorization to do so. Find out more by clicking on this link.


The cost of your DNA test depends on which kind of paternity test you opt for. Cellmark’s home paternity test is priced from £99.99 + VAT and can be ordered online. 

A legal test is more expensive due to the extra processes put in place to ensure the utmost quality standards.

The legal version of the DNA paternity test costs around £324 +VAT for up to 3 individuals (e.g Mother/Father/Child or Father/Child/Child) and then an extra £133 +VAT per additional person. 

Customer Service

CellMark has a high level of customer service with a friendly advice line open 5 days a week, to answer any questions you may have both before and after testing. 

While they do not discuss results over the phone, they can answer written inquiries about specific results and discuss general issues regarding paternity testing. 

You can also access support from a customer advisor via phone, email, or using CellMark’s discreet text messaging service.

Benefits of CellMark’s Test 

  • It’s a highly reliable DNA relationship testing service that has been around for over thirty years.
  • They offer a legal DNA testing service that can be used for immigration applications or custody disputes. CellMark is accredited by the Ministry of Justice.
  • Their next day delivery is standard - so you get a fast turn-around without paying extra. 
  • CellMark has extremely high standards - its quality management system has met ISO standards since 1990 and adheres to the Human Genetics Commissions "Common Framework of Principles on DNA testing".
  • You can get free, confidential advice before and during the testing process. 


  • Slightly more expensive than others on the market 

Frequently Asked Questions 

Why is a paternity test more conclusive if the child's mother is included?

A child inherits half of its DNA from its mother and the other half from its father. When the mother’s DNA is submitted as a sample, it allows geneticists to exclude the proportion of the child’s DNA which is inherited from their biological mother. 

This allows CellMark to exclude the markers which are maternally inherited, and analyze the remaining markers against those of the alleged father's. Therefore, the statistical analysis of paternity can be more conclusive. 

Does the home DNA test arrive in discreet packaging?

Yes. All Cellmark Home DNA kits will arrive in an envelope which has no Cellmark or DNA logo and will be clearly stated as 'Private and Confidential', meaning you can rest-assured that the envelope won't attract any unwanted attention or arouse curiosity. 

Does it matter if I can’t take all the samples at the same time?

No, it doesn’t matter, as the collection card preserves and protects the sample. After your or another person takes the cheek swab, these can be pressed onto the collection card and stored at room temperature in the return bag until all the samples have been taken.

They can then be sealed in the tamper-evident envelope together and returned to CellMark. 

Is relationship testing ever inconclusive?

Rarely is a paternity (or maternity) test inconclusive, however, CellMark may occasionally detect a natural change in one of the DNA markers so it may not match as expected, and this can complicate the analysis process slightly. 

This is very rare though, especially if both parents are tested, as CellMark tests so many genetic markers. 

However, if only one parent is tested, this can lower the statistical results and Cellmark will only be able to confirm that the two individuals are related, not the extent of the biological relationship (if there is one). 

Final Verdict 

If you’re looking for quality, CellMark doesn’t disappoint. They are by far one of the most trusted and longest-standing companies in consumer genetics and are one of the best choices when it comes to legal paternity and relationship tests. 

Not only are these tests easy to use and quick to order, but they have an extremely quick turnaround and you’ll receive your results the next day, at no extra cost. Other DNA testing services usually require additional payments for next day delivery, but CellMark guarantees both efficiency and effectiveness. 

The company also has extremely high levels of quality control and accuracy, thanks to CellMark’s process of testing 24 genetic markers - which is more than other DNA companies test, on average. 

They also offer strong customer service, with trained advisors on hand to answer any queries you may have. 

While you’re likely to find more competitive prices with other brands, CellMark has the advantage of being accredited by several high institutions, such as the Ministry of Justice, and if you opt for CellMark, you’re pretty much guaranteed quality, efficiency, and professionalism. 

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