Forensic DNA Sample
When considering submitting 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 of samples which, depending on the conditions, can be more or less reliable in the extraction of the DNA they provide.
In this sense, laboratories make a clear distinction between two types of samples:
- You have on one side buccal swabs which are always sent in a collection kit when ordering. These are saliva samples whose extraction rate is very high and above all their use is always included in the purchase price of your test.
- On the other side, you have non-standard samples, which represent all elements or supports which may contain DNA and which can be analyzed by the laboratory in order to recover genetic information.
Depending on the situation and the type of test, participants have the choice of submitting the most suitable sample.
The DNA Sampling Kit
When you purchase a DNA test online, you will receive a collection kit, automatically 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.
The kit contains the following items:
- 4 buccal swabs set - 4 buccal 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.
- Laboratory procedures
- Small envelopes to accommodate the swabs after sampling, on which it is possible to write the participant's information.
- A preindexed envelope with the return address . Please note that the return shipment of your samples is not always included by the laboratory and therefore may be at the customer's expense.
Do not reuse the original swab packaging after collection!
What is a DNA Sampling kit?
It is recommended to follow a certain protocol when collecting the samples at home. As a precaution, all participants must have a clean mouth for mouth swabs.
You should not eat one hour before and you should rinse your mouth with lukewarm water before starting the 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, certain 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 seconds and 1 minute the inside of your cheek, with the cotton swab.
- Let the swab dry for 1 hour in the open air indoors. Do not touch the cotton part.
(For this you can use a glass, swab inside and cotton up)
- Once dry, put the swab in the envelope provided in the kit .
- Repeat the step 4 times per participant. Be careful not to mix up participant swabs .
We offer a detailed explanation of the sampling procedure on the page: create your own kit.
What is the collection procedure?
Types of Genetic Samples
There are many situations in which the use of a sampling kit is impossible. This is why laboratories also offer the possibility of using samples called non standards or discrete samples.
The non-standard or discrete sample can cover infinite shapes, and the laboratory can effectively carry out an analysis on any type of support in order to be able to recover the DNA present thereafter.
It is necessary nevertheless to distinguish between samples that come from the person (direct samples) and objects that have been used, consumed or manipulated (indirect samples) .
Direct discrete samples
Hair, nails, blood samples (tube or supporting item), semen (condom or stain), samples of medical procedures, dental samples, a biopsy, muscle samples, bones, ashes...
Indirect discrete samples
- Personal items such as toothbrush, hairbrush, razor, glasses...
- Consumable objects containing DNA such as cigarette butts, chewing gum, handkerchief, toothpick, cotton swab, sanitary towel (tampon), condom, etc.
Using a non-standard sample is an option to your test , which means than in the vast majority you are asked to pay extra to analyse this type of sample, despite the fact that the extraction of the DNA is not 100% guaranteed .
It is up to you to decide if you want to take this risk, because any unsuccessful extraction attempt will be charged. You will have to pay again if you wish to continue the analysis with new samples.
It is therefore very important to favor buccal swabs if possible or to choose the sample carefully before sending it.
Discreet sample is a paid option!
There are a multitude of reasons why choosing a non-standard sample is necessary instead of saliva samples, but in general they are necessary when:
- One of the participants is not available
- When you want to do a DNA test discreetly
Doing a DNA test discreetly can in some cases be the solution to mistrust or doubt about a relationship, without abruptly revealing compromising results.
It turns out that sometimes taking a DNA test or announcing the results to someone can be inappropriate or difficult to live with, that's why solutions exist to operate in complete peace of mind when the question of biological parentage arises seriously.
Nevertheless, the participants' consent is theoretically necessary for any DNA test , even if the laboratory cannot directly control this aspect, the participants take full responsibility for the samples they send. More information about consent
In these terms , the use of a non-standard sample will always be considered an anonymous test and can never have legal value. More information on legal testing and anonymity
Be careful all the same, 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 offender of the test who uses discrete samples, fully assumes his responsibility .
Why choose a non-standard sample?
The reliability of samples for a DNA test
The reliability and authenticity of the test to know the filiation 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 the DNA from the material sent, in order to be able to create the genetic profile of the person.
At this stage of the analysis, not all samples provide the same success rate in the DNA extraction process.
The quality of the extraction will depend on several factors such as storage or the date of sampling, but above all on the type of sample.
It is therefore easier to extract DNA from direct samples or from samples containing emanations from the person such as a stain of blood, sperm, mucus or earwax.
A reliable sample is a sample that will easily provide enough genetic information for the DNA test you ordered. It will then be necessary to choose a certain type of sample, respect the sampling method and keep the sample in order to avoid any type of contamination.
The reliability of a sample will depend on its extraction rate. Under no circumstances will a wrong sample provide a false result.
- 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 analysis.
- If you receive your results, it means that your samples have been correctly analyzed, that the samples have gone well and that a genetic profile has been found.
How to provide a reliable genetic sample?
If possible, do not use samples too old (several years) because they represent a very high risk of degradation.
Obviously, DNA does not stay viable on a material for a long time, and multiple external factors can play a role in DNA wear.
Thus, the question of conservation must be taken into account.
Choose fresh samples
Sample preservation is one of the key things to consider before sending them to the lab. As soon as you have the samples in your possession, please keep them in paper envelopes.
If the sample is too large, in cardboard boxes. In any case, you should not use bags or any other plastic container for the conservation for the sending.
Make sure that the sample, before collection, was in conditions favorable to its preservation.
A humid place outside or in contact with liquid materials 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 from supports that may be in contact with materials such as coffee, tobacco or toothpaste.
Ensure proper preservation of DNA
To avoid contamination of your sample, you must avoid handling it with your fingers.
It is therefore recommended to use gloves whenever possible during sampling.
Naturally, the contamination of a sample by another DNA appears on the analysis.
It is then very difficult for the laboratory to determine to whom the genetic information found on the medium belongs to.
But it is always easy to be able to determine in the contamination if it comes from a male, female or other profile.
If ever the sample that arrives at the laboratory is deteriorated or contaminated, the analysis procedure cannot continue.
If this is the case, the laboratory will always request a resample with the shipment of a new kit.
In this way, a bad sample cannot hinder the reliability of the results .
Avoid DNA contamination
Recommended DNA samples
Blood is the best support for DNA extraction and certainly allows you to obtain a genetic profile. You have the possibility of sending a tube of blood or some blood spots on a material .
- After the blood test, it must be sent in a tube provided for the conservation of blood during transport.
- The blood stain must be greater than 1cm from diagonally and the support must be a cloth, paper, compress, clothing, sanitary napkin…but not all supports can be used.
Please dry the blood before sending.
Shelf life of liquid blood in a tube: 15 days
Lifespan of a dry bloodstain : 3 to 4 months (depending on conservation)
Sperm can be sent on an absorbent material , a wipe, or in a condom . Above all, please dry before sending to the laboratory in a plastic bag.
Lifespan of a sperm stain: 3 to 4 months (depending on storage)
The lab needs 5 to 10 pieces of fingernails to perform a DNA test. Preferably, please choose the toenails , as the fingernails can be polluted in everyday life. Nail varnish or any other product does not affect the analysis.
Depending on the conservation the nail will always have DNA. But they can deteriorate from 6 months after the sampling.
The lab needs 5-10 hairs with the root to perform a DNA test. It is impossible to send hair that has been cut and without the bulb, because the genetic information is located in the living part of the hair which is the follicle at the end. You can recover hair with root on hairbrushes for example.
Depending on the storage conditions, hair will still have DNA, but a degradation may appear 6 months after the sampling.
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 possibility of sending several samples to increase your chances of success. Do not handle the cotton with your fingers, let them dry before sending them in a paper envelope.
The lifespan of DNA: 1 to 2 months (depending on storage)
You can recover a used handkerchief, on paper or on tissue, and let it dry before storing it in a paper envelope. Please arrange to send the sample to the laboratory promptly.
The lifespan of DNA: 1 to 2 months (depending on storage)
The toothbrush is the easiest and most discreet sample to retrieve from a person. However, the DNA present on it can easily be deteriorated with contact with toothpaste.
For collection, be sure that no one else has used the toothbrush and that the person does not wash the toothbrush with toothpaste after use.
Please collect it after use and dry it before storing it in a paper envelope for mailing.
DNA shelf life: Up to 1 month (depending on storage)
All online DNA tests offer you the use of mouth swabs to provide a DNA profile.
So sending non-standard samples will be specific to a number of tests and you may be refused this type of sample for specific tests.
The protocol for non-standard samples
If you wish to send this type of sample for one of the participants, the sample does not have to be the same for all . You can send buccal swabs for the brother for example, 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 blood tubes for the mother and buccal swabs for the father)
- Mitochondrial DNA test (only buccal swabs)
- Test to know the sex of the baby (only blood tubes)
- Genealogy test (laboratories usually recommend mouth swabs)