DNA Diagnostics Centre (formally DDC Laboratories, Inc.) is a leading DNA testing company, focused on the development and marketing of innovative genetic testing products and services. DNA Diagnostics Centre provides easy DNA testing for paternity, immigration, legal purposes, and for clients who wish to discover their genetic ancestry.
Deciding that you need to get a home paternity test done is the hard bit. Actually doing one is very simple. If you don’t need the test for any legal reason such as child support and custody and just want to know for your own information, you can go online to order a home test kit. We recommend that you use a lab like DNA Diagnostics Centre (DDC) that is accredited to ISO 17025, has a good reputation, and maintains a proven track record in the home-paternity business.
How Does a Home Paternity Test Kit Work?
All kits are slightly different depending on the equipment used by the lab during the DNA extraction process. how
Cheek swabs: Most labs use some type of sterile cheek swab (called a buccal swab) to harvest the loose cells from the inside of the cheeks. Some are made of a soft fibre on the end of a stick. They look similar to cotton wool buds but are actually made of a special synthetic fibre called Dacron. These swabs are very good at gently capturing a huge number of cells effortlessly and comfortably.
Cheek brushes: Some labs use a small brush instead but this can be quite abrasive and a little uncomfortable, particularly for children.
All kits contain a receptacle for the swabs to go into once you have collected the sample. Most commonly this is a paper swab-collection envelope, which allows the swabs to dry, thereby preventing mold growth from damaging the DNA sample. At DDC we ask for four swabs per person so that we can run our unique Dual Process wherein every test is run twice as an added layer of accuracy.
What’s in a Home Paternity Test Kit?
If you order one of our no-obligation testing kits, DNA Diagnostic Centre’s paternity test sample-collection kit contains enough swabs to test one possible father, one child, and mother—if she wishes to be included. We encourage mothers to be collected to aid with the paternity calculations but we can still provide an accurate result without her participation.
The home paternity-test kit includes:
12 sterile cheek swabs
Three (3) DNA sample envelopes to place the swabs in after taking the samples
One (1) form for payment details and instructions on how/where to send the results
One (1) prepaid business-reply envelope
One (1) set of instructions
Carefully follow all instructions provided in the kit to ensure that you have collected an adequate sample and to avoid contamination and the need to recollect samples.
If you have any concerns about the sample collection process, or if you would prefer to come to our London office so that one of our professionals could collect the samples for you, please don’t hesitate to contact our very experienced customer service team on: 020 3301 7346.
Can medications or medical treatment affect a paternity test? This is a question we hear very often from clients thinking about doing a test. It is a sensible question to ask since such a large proportion of the population receives regular prescriptions and advanced medical treatments are becoming more commonplace. But what is the influence of modern medicine on paternity-test results?
Does Medication Affect a Paternity Test?
Medication does not impact the results of a DNA test simply because its use does not impact your genetic makeup.
Do Medical Treatments Affect a Paternity Test?
There are some treatments that can affect your DNA and so in turn change a DNA test result—making it more of a challenge to get a conclusive test result. If you or someone else who plans to be tested have had the following treatments, it is important that you understand how this can impact your test and that you tell the lab doing your test about the treatment you have had.
1. Stem cell/Bone Marrow Transplants
Stem-cell transplants used to be known as bone-marrow transplants because the cells were harvested from the bone marrow. With new technology, these cells are now more commonly collected from blood and so are more usually referred to as a stem-cell transplant. These procedures are used to treat certain cancers or blood diseases by producing new healthy cells. Transplants can be from donors or the host can have cells harvested. If you have a transplant from another person, you body will in effect produce your donor’s white blood cells, which contain their DNA. Therefore this may have an impact on your genetic profile. A study by Dr Garima Chaudhary concluded, “Peripheral blood and buccal swab do not serve as a reliable source of recipient’s origin for DNA analysis of individuals who underwent allogenic hematopoietic stem cell transplantation.”
In essence, this means someone who has received a bone marrow transplant should not participate in a DNA relationship test using buccal swabs or a blood sample. You may use other sample sources, however, so you can still do a test. Technologically-advanced testing labs like DDC can also test hair root, for example, since the transplant process does not affect these types of samples.
2. Blood transfusions
If you or a test participant have had a blood transfusion more that two weeks before you provide a buccal (cheek swab) sample, it is highly unlikely this will impact the test result. This is because blood cells that are transplanted have a short life and are constantly being replaced, so they only stay in the body for a short time before breaking down. For any woman who is planning on having the Non Invasive Prenatal Paternity Test, if you have received a recent blood transfusion it is imperative that you let the lab doing the test know. The sample required from the mother for this type of testing is a blood sample, and the lab may well advise that you wait a short time to ensure the transfusion does not affect the outcome of the test.
In a nutshell
If you have had a stem-cell transplant or a blood transfusion, remember this does not preclude you altogether from having a paternity test, but it may make getting a result more difficult. Our highly-trained and experienced customer-service team is on hand to navigate you through the complexities of situations like this. If you let us know your situation, we can guide you and let you know which samples would be the most appropriate for your test.
DNA Diagnostics Center (DDC) has been performing high-quality DNA testing since 1995, and so we’ve probably “heard it all.” As an authority on DNA, we often get inquiries about paternity fraud. Are there ways to “fix” a test in order to manipulate the results? How concerned should people be about the possibility of fraud? Here are answers you really want to know to the top 3 questions we get about this delicate subject.
Q: Paternity Fraud: What if the mother submits her own DNA, pretending that it’s the father’s?A:You needn’t worry, because it won’t affect results.
Sometimes a mother may attempt to submit her own sample for a paternity test, knowing it will show a positive result for a biological relationship (which makes perfect sense, since she’s the mother of the child). However, this is never successful because the lab includes the amelogenin, or sex, gene in its analysis in order to verify the gender of all participants, including the possible father, the child, and the mother. The lab can tell immediately if the sample submitted is a female’s instead of the expected males, and suspends testing without issuing results. The lab then requests new samples before proceeding with the paternity test.
When doing an at-home test, a possible father may commit paternity fraud by swabbing someone else’s cheeks and submitting that man’s DNA as if it were his own. This can definitely affect results, since the integrity of the samples has been compromised. If the possible father actually is the biological father of the child being tested, the report would nevertheless show a 0% probability of paternity since it was not his DNA that was tested. Keep in mind that a mother could also swab someone else and try to pass off the sample as her child’s, and that is also fraud.
Be each other’s witnesses: If you have any reason to suspect the mother or possible father might try to submit someone else’s samples as their own, insist on collecting DNA together in the same room and insist on mailing the sample envelopes off as a group. When you act as each other’s witnesses, you can each be sure that no fraud has taken place.
Choose a legal test with court-admissible results: It may be worth your while to pay a little extra for a legal paternity test collection. If you cannot be each other’s witnesses, then perhaps an at-home test is not the best option for you. With a legal paternity test, DNA collection and submission of samples to the lab are witnessed at an approved facility. The lab makes all arrangements for DNA collection—no matter where participants live—so you can be sure the risk of fraud is nil.
Q: Paternity Fraud: Can results be changed by eating or drinking before DNA collection?A: No, that’s not possible at all.
It is recommended that participants in a test not eat, drink, or smoke for one hour prior to swabbing their cheeks. So sometimes, people who want to purposefully commit paternity fraud assume that if they do any or all of those three things, then the result of their DNA test can be falsified. The truth is that DNA cannot be “changed” by eating, drinking, etc.: it can only affect the “quality” of the sample. If one or more swabs submitted are contaminated by food residue, breast milk remnants, or other matter, making it impossible for the robots to extract DNA, then testing is suspended until new samples can be obtained.
We do everything we can to safeguard against paternity fraud, but it’s important that participants in testing do their own due diligence to ensure samples submitted for testing belong to the right people. It’s the wise and cautious thing to do!
If someone chooses DDC for their paternity testing needs, the lab provides the client with a detailed explanation of results with the report. Due to the nature of the test, it inevitably includes some legal and scientific wording that may be unfamiliar to a layman. Be assured the lab provides a very comprehensive explanation in plain English, but for the sake of clarity, here is an explanation of what the more complex or technical words mean along with a simple guide on how to interpret your report.
Please be aware that this guidance only relates to tests where the child has been born and has provided a sample. These notes are not relevant to any non-invasive prenatal testing. If you need assistance with understanding a prenatal report, please phone our customer service team on 020 3301 7346.
DDC Paternity Test Results at a Glance
There are four areas on the report:
A chart containing the tested parties’ DNA profiles
The Combined Paternity Index (CPI)
Probability of paternity
The conclusion reached about the relationship
To ensure a very-high-quality test, DDC examines a minimum of 20 genetic markers. In addition, the lab also looks at the Amelogenin (sex) gene for each participant. The report’s chart displays the genetic profiles of the alleged father and child—and also the child’s mother if she has been included in the testing. On occasion the lab may decide, at no extra cost to the client, to test additional markers where they believe the additional data would be beneficial to providing a definitive outcome. In these instances, they will also include any additional testing data within the body of the report.
Children inherit one genetic marker from each biological parent. Therefore the principle behind testing is quite straightforward. If there is a mismatch between one of the child’s markers and that of the alleged father, then there is a possibility that he is not the biological father. Where there is a match at a genetic location (locus), a paternity index number is generated from a database for the ethnic group to which the father belongs. The frequency in which that allele occurs within the specific ethnic group directly relates to the PI. The more rare it is, the higher the PI.
One question that is asked frequently is how sometimes only one allele value (represented by a number) appears at a given locus. How is this possible if a child should show two allele values at each locus—one allele inherited from the mother and one from the father? To put it simply, where a child has two identical alleles, we only report it once.
Example: If a child expresses values of 15, 15 at a locus (one 15 inherited from the mother and one 15 inherited from the father), the report shows the genetic data as just a single 15.
Combined Paternity Index
The Combined Paternity Index (CPI) is located on the lower left-hand side of the report, within the Interpretation section and underneath the genetic profile chart.
In cases where the relationship has been proven, and the possible father is considered the biological father, there is a figure listed. This is a statistical calculation that is made using all of the paternity indices listed in the chart.The calculation generates the genetic odds that the man being tested is the genetic father as compared to a random male of the same ethnicity. This number will vary from case to case depending on the combination of markers shared between the chid and alleged father. So even two children born to the same parents will most likely have varying CPIs—unless they are identical twins.
Example: If the test shows a CPI of 43,450,497, the way to read this is: “The man tested is 43,450,497 times more likely to be the biological father of the child tested than an unrelated, untested man of the same ethnic background.”
If the alleged father has been excluded as the biological father, then the figure showing is a 0.
Probability of Paternity
Right next to the CPI is the Probability of Paternity percentage. To get this number, the analyst applies Bayes Theorem to the genetic data from the test. Since DDC tests as many genetic markers as necessary to get conclusive results, the probability of paternity for a positive test is usually 99.9% or higher. When the man tested is not considered the biological father, the probability of paternity is 0%.
NOTE: A probability of paternity can never be 100%. Remember, statistics are used to calculate this number, and so it could never be 100% unless every man I the world with the same ethnic background were tested…and of course, that’s not possible!
Paternity Test Conclusion
The final conclusion of the test can be found in the interpretation section at the bottom of the report. This is the scientific opinion of the highly-qualified PhD responsible for your test. They way we have to word this causes the greatest confusion about the test outcome.
If the alleged father is not excluded, this means that the likelihood falls to his being the biological father, and he has not been ruled out of being the biological father.
If the biological father is excluded as the biological father, it means that he cannot be the biological father of the child.
If you are still unsure about your results report, we are happy to provide additional guidance and information. Phone one of our highly-experienced customer-service staff on 020 3301 7346.
Can you use a sibling DNA test for immigration? Yes, you can. If the sponsor is a sibling, the authorities will most likely want DNA evidence in conjunction with any other documented evidence. Both full sibling and half-sibling reports are now commonly used as proof of relationships between brothers and sisters.
How Probability of Relationship Works with a Sibling DNA Test
Unlike paternity testing that provides either 99% or higher or 0% probability of relationship as the only two results, sibling testing is based on a percentage of probability that can fall anywhere between 0% and 99%.
If your result is in excess of 90% this would be considered proof that the sibling relationship exists. Anything under 9% suggests that it does not. A result in between these two figures is considered inconclusive. Labs like DDC can test many more markers than the industry standard, and so fortunately, inconclusive results are unusual. Where lab staff believe that the addition of another relative’s DNA may be beneficial, we will contact the family and offer to include them at no extra cost.
Sibling DNA Tests for Immigration Purposes
Most individuals going through an application or appeals process will have engaged a solicitor specialising in immigration, so it is always a good idea to clarify with them the need and nature of any DNA tests that you plan on having.
There are some important points to consider when having a sibling test:
Make sure that the lab that you use is accredited by The Ministry of Justice
You or your solicitor can request the testing from a MOJ lab if the test is not for a passport application
If you need a sibling test for a passport application, HMPO will advise you which lab you need to use and when you need to attend for your sample collection. DDC is one of the labs contracted to do these types of tests
Wherever possible, include the mother of the siblings. If the siblings have different mothers, include both if you can. The test cost is basically the same—there may be an additional but small sample collection fee—but having a mother can significantly improve the probability percentage in positive tests
When choosing a lab, ensure that they test at least 20 markers and ask if they can test additional panels of markers if necessary
Why You Should Choose DDC for your Sibling DNA Test
The Ministry of Justice accredited DDC in 2008 and our reports are recognised by the immigration authorities
DDC is the most accredited private DNA testing lab in the world including ISO 17025
We test a minimum of 24 genetic markers for all our relationship tests and we will test more where necessary at no extra cost
We test to reach the most definitive conclusion possible because we understand the importance of bringing families together
We have a global network of collectors so even if you loved ones are abroad, we can arrange to have their samples collected by trained, reliable medical staff
DDC has global experience of working with HMPO, Visa Centres and embassies
If you need any advice about the testing process or which test is most suitable for you, please call one of our highly-experienced customer-service staff on 020 3301 7346.
Because DDC is such a well-known and highly-accredited lab, we are often asked, “How soon can I do a paternity test after the baby is born?” Some people will not want to wait until the baby is born and will opt to have a non-invasive prenatal paternity test, but for those who don’t choose that option, the next best thing is to clarify the biological relationship as soon as possible after the baby is born. Having a new baby and questions about the baby’s paternity can be hugely stressful, so many new parents want to start the process before the baby has even been discharged from the delivery ward. But is that even possible?
Yes, testing can be done as soon as the baby is born. Once the new arrival has been checked over by medical staff, a sample can be taken for a paternity test.
How to Collect a DNA Sample from a New Baby
It is important to make sure that the baby doesn’t have any amniotic fluid, meconium, or breast milk in its mouth because cheek swabs are used for paternity testing; any of those fluids could cause DNA contamination and possible delay results
It is a really good idea to take a sample from a newborn while they are sleeping. Babies sleep so deeply, they won’t even be aware you are taking a sample and it makes it much easier when they remain still
Place your hand gently against the outside of the baby’s cheek. This way you can feel where the swab is and will be sure it is gently making contact with the inside of the cheek and not the gums. Carefully rub the swab back and forth for half a minute. You are trying to collect cheek cells, with as little saliva as possible
Babies can produce a lot of saliva, so the swab may get very wet. If this is the case, just hold the swab for about a minute and let it air dry. Be careful that the swab tip does not come in contact with anything and then place inside the paper swab envelope and seal
Important Things to Consider
Everyone wants to have a stress-free pregnancy and birth, but this is difficult if there is a question hanging over the paternity of the new arrival. Just having to raise the issue of paternity and a DNA test with a partner or potential parent can be very difficult. If you deal with this quickly and establish the facts, it will be easier for you all to move past the uncertainty—no matter the outcome. If it turns out the alleged father isn’t the biological father after all, it’s best to know before a bond is made with the baby.
If you think you may need results for child-support or child-custody petitions, be sure to get a legal paternity test, so that the report can be used in court. Results from an at-home kit cannot be used in court.
What is really most important is that every child should have a right to know who their biological parents are, for emotional reasons, but also in case they may be at risk of genetically-inherited diseases.
You’re probably familiar with the concept of paternity testing, but what can someone do if the alleged father is not available to provide a sample? You may be asking, “Can I do a paternity test without the father?”
There are many situations that can make it impossible to test the alleged father. He may simply be unwilling to cooperate, he may be absent for other reasons or he may have passed away. There is an assumption that nothing can be done, but do not despair! Although it’s always optimal to include the alleged father, there are definitely other options for establishing the paternity of a child. If you are unsure about what to do or how to get started, it’s well worth your while to call a well-established, accredited lab. They should be able to talk through your particular situation and identify what other options you might have with testing relatives of the alleged father.
Options for a Paternity Test without the Father
You need the willing participation of one or more of his biological relatives. Typically this can include:
Other known children
The mother and/or father of the absent father
Full siblings of the alleged father
IMPORTANT NOTE: It is extremely important to include the child’s mother in any of the tests detailed below. This allows the lab to exclude the mother’s contribution to the child’s DNA profile; what is left will have come from the biological father—and it is this contribution that can then be compared to genetic data from his biological relatives.
Grandparentage DNA Test
A grandparentage test uses DNA samples from the alleged father’s mother and father and is the most desirable option for conclusive results. If you can provide samples for both parents the test result can be as definitive as a paternity test. Using just one grandparent of the child is still a good option, but the more data, the better.
Aunt/Uncle DNA Test
DDC has the capacity to run extended testing at our high-tech lab. This means we can look at significantly more DNA markers in these tests than the industry standard. This makes our tests more accurate and in many cases give a more conclusive result. An uncle or aunt test that includes the child and their mother is a good option if grandparents are unavailable.
Siblingship DNA Test
If the absent father had any other children, then this is a really good option. If both children share the same mother, the test is a full sibling test. If the other child has a different mother, then you should order a half-sibling tests. If the children do not share the same mother, it really is a good idea to test both mothers so that their genetic contributions to the children can be excluded.
How These DNA Tests Are Used
Tests with at-home DNA collection can only be used for peace-of-mind and informational purposes. If you need to prove paternity for a legal purpose, then all of these tests can be used, as long as DNA collection is witnessed. This is done very often for immigration cases. If the father has passed away recently, there may be an option to perform a paternity test from a post-mortem sample. For any additional information or guidance, please do not hesitate to contact our experienced customer-service team on 020 3301 7346.
One of the most common questions we are asked when someone wants a test is: “Are home DNA paternity tests accurate? Many people are concerned that they may not be as reliable as a test where samples are taken by a third party such as a doctor or an approved DNA collection site.
Depending on the results, taking a paternity test can have lifelong ramifications for any family, so it is a very sensible question to ask. For that reason we have provided an overview so you can make an informed decision about the test that may be best for you.
Accuracy of Home DNA Paternity Tests
If you are considering taking a home paternity test, the first thing you should do is make sure that you use an accredited laboratory. You should look for an ISO17025 accreditation. This is a specific standard for DNA relationship testing. This way you can be confident that your test results will be 100% accurate for the samples that you send to the lab. Keep in mind that the lab relies on the person collecting the samples to provide them from the correct individuals. Because the identities of participants in a home test cannot be independently verified, results are not court admissible. If you need results for court, then a legal paternity test is a better choice.
Is a Home Paternity Test as Accurate as a Legal Paternity Test?
In terms of process, the only difference between a home paternity test and a legal paternity test is how DNA samples are collected before they are sent off to be tested. But once the samples arrive at an accredited lab, the entire testing process is as stringent as it would be if they received samples for a court-approved test. They will use the same technology and exacting testing standards irrespective if your test is a home paternity test of a legal paternity test.
If it is Only Possible to get a Result of 99.9% how can that be 100% Accurate?
100% accuracy and 99.9% (or higher) probability of paternity are two different things. The accuracy refers to the quality of the test process. A test can be 100% accurate in that the test is absolutely correct with no errors for the samples provided. It does not mean that there is a 100% probability in the paternity conclusion.
Why a Paternity Test can Never Show a 100% Probability of Paternity
Individuals can share a significant amount of DNA markers even when they are not related: it’s just part of being human. This is why paternity is reported as a percentage of probability. To ever get a 100% probability of paternity, we would need to test every man in the world with the same ethnicity as the alleged father. Clearly this isn’t an option, so a statistical calculation is made to provide the probability. The test is done by calculating the frequency of the shared alleles within the ethnic group of the parties being tested. It makes the test incredibly accurate and a probability of 99.9% or over is considered a conclusive, positive result for paternity.
Accredited DNA testing is 100% accurate based on the high quality testing process. This can generate a probability of 0%, which can exclude the alleged father from being the biological parent or it can produce a result of 99.99% in favour of the paternity relationship existing.
Although it is occasionally made light of on some television programmes, DNA paternity testing is actually very sophisticated science that provides life-altering answers to participants. It’s hard to believe that reliable results have only truly been available to everyone for just a few short decades, but it’s true. Here is a brief look at paternity testing through the years.
1920s: Blood Typing
Some people will be very surprised to know that the first cases of paternity testing happened in the 1920s, with the advent of blood-type testing. Four distinct blood types were identified: A, AB, B, and O. As blood types are genetically inherited, it was in some cases possible to exclude a father if the child’s blood type did not match either the father or the mother. It could not provide absolute proof of paternity, but in some cases it could provide proof that the father and child were not genetically related.
1960s and 1970s: Here Comes DNA
It was not until the 1960s that any form of accurate genetic paternity testing became available with the arrival of HLA typing. This type of paternity test compared the genetic fingerprints of white blood cells between a child and their biological father. While these tests don’t give the same accuracy as a modern paternity test, they were achieving an 80% accuracy. What these tests couldn’t do was to distinguish between individuals that were close relatives.
More accurate testing began in the 1970s when the first restriction enzyme was isolated.
1990s: Ground-breaking Analysis Using PCR
Reliably-accurate testing was not available until the 1990s, when a process called PCR (Polymerase Chain Reaction)—actually developed a decade before—was utilised in testing. This is the testing process that is used today, not only in paternity testing, but also as the ultimate method of identification of an individual globally—particularly for law enforcement.
How PCR Works
Because DNA is so infinitesimally small, an effective way to duplicate (and therefore enlarge a given sample) of DNA is necessary. Polymerase Chain Reaction, or PCR, is a technique that allows the generation of millions of copies of targeted areas (loci) in the DNA. PCR harnesses the cell’s ability to replicate DNA before cell division, but in a test tube. PCR is used commonly in the scientific community to perform a number of different tests and is used by DDC for paternity testing. Once the DNA is extracted, it is combined with chemicals to support the PCR reaction. These chemicals include primers, which are small pieces of synthetic DNA labeled with florescent tags that flank the region, as well as the DNA building blocks (A, T, C, G), and an enzyme to support the replication of the DNA.
For paternity testing, DDC uses a multiplex PCR reaction that tests 21 different locations (loci) in the DNA at once. This is accomplished using an instrument known as a thermocycler that heats and cools the DNA. Each round of heating and cooling doubles the amount of DNA at the target locations, so that—after 28 cycles of heating and cooling—over a million copies of each strand of DNA are present and ready to be analysed.
Comparing the DNA profile of child with an alleged parent using PCR can show whether one of them was derived from the other. This is why modern paternity testing is so reliable compared with previous efforts.
These Are Fortunate Times
Thanks to these scientific advances through the decades, families can now get answers to biological-relationship questions more reliably, more quickly, and definitely more affordably than could have ever been imagined just a few generations ago.
As a top paternity lab we often get asked, “If I’m considered the biological father, why do my test results show 99.99% and not 100% probability of paternity?” That’s an excellent question, and it’s also a scientific one. Here’s an explanation in layman’s terms about why probability of paternity can never—that’s correct—never be 100%.
How a Baby Inherits DNA from its Parents
During the reproduction process, the DNA of two individuals together—mother and father—randomly produces a very unique combination of genetic markers in each cell. This combination of markers is unique to the new person they create together.
The genetic material of a child is inherited from the parents in equal portions, hence the child’s genome as presented in a paternity report reflects the 50% DNA they get from their mother and the 50% DNA they get from their father.
In order for the man tested to be considered the biological father of the child tested, there must be a match between them at each one of the locations tested, although there may be an exception made for a known genetic mutation. So if a man matches the child at each location tested, shouldn’t the probability of paternity be 100%? No, and this is where the science comes in.
Why Probability of Paternity Can Never be 100%
Comparing the DNA sequence of a child to a parent can identify if one of them was derived from the other. This does not mean that we can achieve a probability of 100%.
When considering the possibility of paternity, specific sequences are reviewed and ethnic data are used to calculate a probability of paternity. Analysis required for paternity testing is all about statistics and the only way a man could ever be considered the biological father with 100% probability is if every man in the world with the same ethnic background were also tested. Of course, this is impossible!
Basics of Calculating Probability of Paternity
Paternity Index: The probability of match between alleged father and child at each genetic location has its own calculation, called a Paternity Index (PI). The strength of the match at that location is determined by a variety of factors.
Combined Paternity Index: We generally test a minimum of 20 genetic locations, and—as mentioned—each has its own associated paternity-index value. The PI are multiplied together to get what’s called a Combined Paternity Index (CPI). And that number is the statistical probability of relationship. In the example below, the CPI is 1,716,973,979. This could read: The man tested is 1,716,973,979 times more likely to be the biological father than an unrelated, untested man with the same ethnic background.
Using the strength of the genetic results in the Combined Paternity Index, a Probability of Paternity is calculated. We’ve already established that number can never be 100% unless every man in the world can also be tested. But the higher the CPI, the higher the Probability of Paternity. Anything over 99% is considered conclusive. This example shows an extremely high CPI; the minimum for a CPI to be considered conclusive can be as low as 100 for an at-home test and 200 for a legal test.
But What if there is a Mismatch at a Genetic Location?
If there is no match at one (or more) of the genetic locations tested and the mismatch isn’t due to a known mutation, the PI for that location is 0 %. This means that when all PIs are multiplied together, that one 0% makes the Combined Paternity Index 0%, and the man is not considered the biological father.
If the DNA of two individuals don’t match, then we can say with 100% certainty that a man is not the biological father of a child.
So What Does This All Mean?
A 99.99% probability of paternity is so powerful, that it’s routinely accepted as evidence in favour of paternity by genetic scientists, courtroom judges, and the Ministry of Justice. The upshot is: A DNA paternity test probability of 99.99% is strong enough for a judge to confidently allow (or deny) child support, immigration, or even conviction in a criminal case.
Need a paternity test? Don’t hesitate to call us at 020-3301-7346: We’re here to assist you.