How Are DNA Tests Done? What Do They Consist Of?

Performing a DNA testing is a common procedure among those who want to prove the paternity of their son or daughter, know the relationship between individuals, tests for surrogacy or for more and more genetic tests.

Depending on the purpose and destination of these tests, the application and performance procedures will vary and will be carried out under specific conditions.

Differences between informative and legal DNA testing

The most notable changes and differences between judicial and private DNA testing in this regard are as follows:

Private or informative DNA tests: in these tests, the names of those involved do not appear in the report. The interested party can carry out the test at home, without having to go to a laboratory or medical center. They have no legal validity.

Legal DNA tests: these are requested by means of an expert report and are supervised, carried out and guarded by judicial and health personnel. Each of them must be certified to do so. On the other hand, the results reports include the names of those involved in the test.

Legal DNA tests are usually those that involve a stricter and more protocolary process, as a 100% reliable result without errors is required. However, the steps to be followed to carry them out are the same in both.

Steps to follow to perform a DNA test

Collect the sample:

The required samples must be biological and belong to each of the subjects whose parentage is to be analyzed. The buccal smear has become the star process for collecting samples. It responds to a process of direct extraction of oral fluids.

However, it is also common to do so through body fluids such as sweat, semen, urine and blood, or nails, hair and objects used by the subject. This type of extraction is called indirect.

Analyze the sample:

Once in the laboratory, the sample is analyzed and the DNA is extracted, as well as purified. After that and following the process called Polymerase Chain Reaction Technique (PCR), the DNA is subjected to amplification to increase the presence of specific sections of each individual.

The sections obtained are the STR (Short Tandem Repeat), which offers a clear and exact sample of their length and repetitions. In other words, you see how the DNA chain is formed. In this way, when comparing it with the other individual’s chain, coincidences or differences will be better appreciated.

Examine DNA sections:

The process described in the last lines of the previous point consists, in one way or another, of this point 3. Once the sections and the structure of the subjects’ DNA chain have been obtained, each and every one of these parts must be examined thoroughly. Thanks to this, the geneticist will obtain a greater security in his results.

As an example, for a paternity test, the professional must make sure that the DNA chain of the child coincides with those of the father and those of the mother at 50%. In other words, the child’s chain must have 50% of the mother and 50% of the father.

Formalization of the test:

At this point, the different procedures carried out by the laboratories come into operation. However, what is clear is that depending on the destination of this test, the procedure will require more or less supervision.

For those who want a formal, legal and legal DNA test, the user must provide their personal data and identification, including legal documents relating to the request for the test. Those who want to request a particular paternity test, with their personal data (name and address) is sufficient.

As can be seen, the nature of the DNA evidence is extremely binding and procedurally relevant. Many patients and users who carry out this request do not usually take this distinction into account. Doubts and misunderstandings are therefore very common.

Broadly speaking, it should always be borne in mind that a legal DNA test is addressed to a court. This means that its result requires guarantees and much more precise, assured and rigorous procedures, since the jury’s decision will depend on it.

On the other hand, home-made evidence is addressed to the user who requests it. This does not involve third parties or procedures as rigorous at the legislative and protocol level as the other test does.

This does not mean, of course, that the accuracy of both DNA tests is higher or lower depending on their character. On the contrary, both are as accurate as any other DNA test or clinical analysis. The difference lies in the procedural protocol, but not in the safety and accuracy of the results.