Forensic DNA Sample
When looking to submit a DNA test, the first question you need to think about is what type of sample you can use . There are indeed a large number which depending on the conditions can be more or less reliable in extracting the DNA they provide.
In this sense, the laboratories make a clear distinction between two types of samples:
- On one side you have the mouth swabs which are always sent in a collection kit when ordering. These are saliva samples with a very high extraction rate and, above all, their use is always included in the purchase price of your test.
- On the other side you have the non-standard samples , which represent all the elements or media which may contain DNA and which can be analyzed by the laboratory in order to retrieve genetic information.
Depending on the situation and the type of test, participants have the choice of submitting the most suitable sample.
The DNA Collection Kit
The kit contains the following:
- 4 mouth smears - Oral swabs per participant.
- Direct debit instructions
- Consent forms that must be completed by DNA test participants.
These forms must be completed and sent to the laboratory, otherwise no analysis can be carried out.
- The terms and conditions of the laboratory
- Small envelopes to accommodate swabs after sampling. On which you have the possibility to enter the participant's information.
- A pre-indexed envelope with the return address . Please note that the envelopes provided by the laboratory are not necessarily pre-stamped. And the sending of the samples is the responsibility of the customer.
Do not reuse the original swab packaging after collection!
Types of Genetic Samples
The reliability and authenticity of the test to find out the parentage link depends on several factors:
- The quality of the samples
- Laboratory accreditation
- The choice of the test according to the family situation
When a laboratory receives a sample, the first step in the analysis is the extraction of DNA from the medium sent, so that the genetic profile of the person can be created. At this stage of the analysis not all samples provide the same success rate in the DNA extraction process.
The reliability of samples for a DNA test
Recommended DNA samples
The protocol for non-standard samples
All DNA tests online offer you the use of oral swabs to provide a DNA profile.
So sending non-standard samples will be specific to a number of tests and you may be denied that type of sample for specific tests.
There are a multitude of reasons why the choice of a non-standard sample is necessary instead of saliva samples, but in general they are necessary when:
- One of the participants died
- When you want to do a DNA test discreetly
Do a DNA test discreetly can in some cases be the solution to mistrust or doubt in a relationship, without abruptly reveal compromising results . It turns out that sometimes doing a DNA test or announcing the results to someone can be inconvenient or difficult to live with, which is why solutions exist to operate in peace when the question of biological parentage arises seriously.
Nevertheless the consent of the participants is theoretically necessary for any DNA test , even if the laboratory cannot directly control this aspect, the participants take all their responsibilities concerning the samples they send.
In these terms the use of a non-standard sample will always be considered as an anonymous test and can never have a legal value. More information on legal testing and anonymity
Be careful though, the consent of the participants is systematically necessary to carry out a DNA test. Thus, the analysis of genetic fingerprints without the consent of the sampled person is accompanied by a criminal sanction. Regardless of the country or the case, the test offender who uses discrete samples fully accepts their responsibility .
Why choose a forensic sample?
When you purchase a DNA test online, you will receive a collection kit. systematically sent by the laboratory. This kit avoids any complications and gives anyone what they need to be able to take their samples at home without the help of a professional . It therefore allows the simplification of the procedure.
What is a DNA collection kit?
It is recommended that you follow a certain protocol when collecting samples at home. As a precaution, all participants should have their mouths clean for oral swabs .
You should not eat an hour before and you should rinse your mouth with lukewarm water before starting to take samples. Do not use mouthwash or toothpaste . The same goes for any consumption of alcohol or tobacco, which can alter the sample .
In such conditions, many times of the day should be avoided so as not to pose a problem. The best time to do this is a few moments after waking up . Thus, the person is generally on an empty stomach and has not ingested anything for several hours.
When is the best time to collect DNA?
- Rub between 30 sec and 1 minute the inside of your cheek, with the cotton swab.
- Make air-dry the swab indoors for 1 hour. Do not handle the cotton part.
(For this you can use a table glass, cotton swab inside up)
- Once dry, put the swab in the envelope provided in the kit .
- Repeat step 4 times per participant. Be careful not to mix up the swabs of the participants .
We offer an explanation details of the sampling procedure on our page create your own kit.
What is the collection procedure?
There are many situations in which the use of a collection kit is impossible. This is why the laboratories also offer the possibility of being able to use samples called non standards or discrete sample.
The non-standard or discrete sample may overlap a infinity of forms and the laboratory can effectively carry out an analysis on any type of support in order to be able to recover the DNA present on it . It is necessary nevertheless distinguish between samples that come from the person (direct samples) and objects that have been used, consumed or handled (indirect samples).
Direct discrete samples :
Hair, nails, blood sample (tube or support), semen (condom or stain), medical procedures, dental samples, a biopsy, muscle sampling, bones, ashes ...
Indirect discrete samples :
- Personal items such as toothbrush, hairbrush, razor, glasses ...
- Consumable items containing DNA such as cigarette butts, chewing gum, handkerchief, toothpick, cotton swab, towel hygienic (tampon), condom ....
Please note that the use of a non-standard sample represents an option for your test , which means that in the vast majority of you are asked to pay extra to analyze this type of sample, despite the fact that extraction DNA is not 100% guaranteed . It is up to you to judge whether you wish to take this risk as any unsuccessful extraction attempt will be charged. You will have to pay again if you wish to continue the analyzes with new samples.
It is therefore very important to give preference to oral swabs if possible or to choose the sample carefully before sending it. In this article, we offer you some advice to put the odds in your favor.
The discreet sample is a paid option!
A reliable sample is one that will easily provide enough genetic information for the DNA test you ordered. It will then be necessary to favor a certain type of sample, respect the sampling method and keep the sample to avoid any type of contamination.
The reliability of a sample will depend on its extraction rate . Under no circumstances can a bad sample provide false results .
- If your sample does not contain enough genetic information for the test, the laboratory will ask you to provide a new sample to continue the analyzes.
- If you receive your results, it means that your samples were correctly analyzed, that the samples were taken correctly and that a genetic profile was found.
How to provide a reliable genetic sample?
If possible do not use samples too much old. Indeed, the use of samples which come from or were in contact with the person several years ago represents a very high risk of degradation . Well obviously DNA does not stay on a medium for that long and multiple external factors can play a role in DNA wear . Thus the question of conservation must be taken into account.
Choose recent samples
Preservation of the sample is one of the key things to consider before sending it to the laboratory. As long as you have the samples in your possession, please keep them in paper envelopes . If the sample is too big in cardboard boxes. Under no circumstances should you use bags or any other plastic object for storage for the shipment.
Make sure that the sample, before collection, was in favorable conditions for its conservation. A humid place, outdoors or in contact with liquid material can very quickly deteriorate the DNA present on it. If you have any doubts, try to find another sample. For example, there is much less chance of extracting DNA on media which may be in contact with materials such as coffee, tobacco or toothpaste.
Ensure the proper conservation of DNA
To avoid the contamination of your sample you must avoid handling it with your fingers . It is therefore recommended to use gloves whenever possible during sampling.
Indeed the contamination of a sample by another DNA appears on the analyzes. It is then very difficult for the laboratory to determine who owns the genetic information found on the medium. But it is always easy to be able to determine in the contamination whether it comes from a male, female or other profile.
If ever the sample arriving at the laboratory is deteriorated or contaminated, the analysis procedure cannot continue .
If this is the case, the laboratory will always request re-sampling with the shipment of a new kit.
In this sense, a bad sample cannot hinder the reliability of the results .
Avoid DNA contamination
Blood is the best medium for DNA extraction and is sure to provide a genetic profile. You have the option of sending a tube of blood or blood stains on a support .
- After the blood test, it must be sent in a tube intended for the preservation of the blood during transport.
- The blood stain must be greater than 1cm diagonal and the support must be a cloth, paper, a compress, a garment, sanitary napkin .... Please note that all the supports cannot be used.
Please dry the blood before sending.
Shelf life of liquid blood in a tube: 15 days
Lifespan of a bloodstain dry: 3 to 4 months (depending on conservation)
Blood Sample for DNA testing
The semen can be sent on an absorbent medium , a wipe or in a condom . Please especially dry before sending to the laboratory in a plastic bag.
Lifespan of a sperm stain: 3 to 4 months (depending on storage)
Sperm sample for DNA test
The lab needs 5 to 10 pieces of fingernails to perform a DNA test. Rather, please choose the toenails preferably, as the fingernails can be polluted in everyday life. The varnish or any other product does not affect the analyzes.
Depending on the conservation the nail will always have DNA. But a deterioration can appear 6 months after the samples.
Nails DNA Collection
The lab needs 5-10 hairs with the root to perform a DNA test. Without this, if the hair or simply was cut you will not be able to use it because the genetic information is located in the living part of the hair which is the bulb at the end. You can recover hair with roots on hairbrushes for example.
According to the conservation of the hair will always have DNA. But a degradation can appear 6 months after samples.
Hair DNA Collection
You must be sure that the sample has not been used by more than one person and that there is sufficient earwax for the test. You have the option of sending multiple samples to increase your chances of success. Do not handle cotton with your fingers, let it dry before sending in a paper envelope.
DNA lifespan: 1 to 2 months (depending on storage)
Using contons-bud as forensic sample
You can collect the used handkerchief in paper or tissue and dry it before storing it in a paper envelope. Please ensure that the sample is sent to the laboratory quickly.
DNA lifespan: 1 to 2 months (depending on storage)
Using tissues as forensic sample
The toothbrush is the simplest and most discreet sample to collect with of somebody. Unfortunately the DNA on it can easily be deteriorated with contact with toothpaste. For the sample, be sure that no one else has used the toothbrush and that the person is not washing the toothbrush with toothpaste after use. Please collect it after use and let it dry before storing it in a paper envelope for mailing.
DNA shelf life: Up to 1 month (depending on storage)
Using Toothbrush as forensic sample
- Paternity test
- Maternity test
- Fraternity test
- Avuncular test
- Grandparents test
- Y Chromosome Test
- X Chromosome test
- Twin test
If you want to send this type of sample for one of the participants, it is not mandatory that the sample be the same for all . For example, you can send mouth swabs for the brother, hair for the sister and nails for the mother. This will have no impact on the results if the samples are different from one participant to another.
The list of DNA tests that accept discrete samples
- Prenatal paternity test
(It is mandatory to send tubes of blood for the mother and oral swabs for the father)
- Mitochondrial DNA test (Only oral swabs)
- Test to know the sex of the baby (Only blood tubes)
- Genealogy test (Generally laboratories recommend oral swabs)
The list of DNA tests that do not accept discrete samples
The quality of the extraction will depend on several factors such as storage or the date of collection, but above all on the type of sample. This makes it easier to extract DNA from direct samples or from samples containing human fumes such as blood, semen, mucus or earwax.