DNA samples which are not the standard saliva samples are called forensic DNA samples or discreet samples. There are so many discreet samples that can be used that it is important to be aware of which samples are better than others so as to maximize the possibility of having reliable paternity DNA testing, infidelity DNA testing or any other results for your DNA test.

Razor DNA testing and envelope DNA testing are amongst the less reliable DNA samples. Below we highlight some other low-success samples.

Post Humus DNA Testing after the Body has been Cremated: normally cremation means that the whole body is reduced to ashes, or to be accurate, dry bone fragments that are turned to dust. Standard cremation destroys the entire DNA because the bonds that hold the DNA together (phosphodiester bonds) are broken and will almost certainly not even provide the slightest traces of DNA. However, if there are bones, then some material may be preserved such as the bone marrow and this may be used for a test. However, again, the laboratory analysis involved in such a test is not the type generally employed by DNA testing companies. Here is an article about paternity testing on the deceased.

DNA Testing with Faeces: using faeces to conduct a DNA test is not considered to be a high-success sample. Samples must be collected within the first 24 hours of having been defecated as the DNA profile tends to degrade rather quickly in this case as the sample is naturally contaminated. Moreover, it is considered to be a hazardous sample to send through the post and requires particular packaging.

DNA Tests with Fingerprints: finger prints do contain some cells that natural detach themselves from the skin surface along with natural oils we secrete. In a fingerprint, forensic experts can find traces of drugs that have been ingested, including cigarette smoke as these are secreted through our sweat and oils. Fingerprinting still finds uses in identification purposes and the FBI still hold an archive with millions of fingerprints and criminal records. It is still widely used during police investigations, but for the scope of paternity DNA testing or any other type of DNA testing, fingerprints are not considered as viable mediums for sampling.

In some countries there are laws which strictly limit the removal and use of human DNA. To take DNA samples from any person without their explicit consent would be considered an offence and subject to legal prosecution. You should thus again, seek advice from the company you choose to give you all the information regarding any laws there may be. In the UK, one of the only countries to have such a law, there is the Human Tissue Act. Obviously, forensic investigations at a crime scene are exempt from such laws.

For a list of samples often used in DNA testing, click here.

As mentioned, some DNA samples are not viable to use or though viable, offer a low success rate. Sometimes the DNA is far too quickly degraded because of both environmental conditions and the medium the sample is suspended in (for example, a DNA test with vomit; vomit is highly acidic). In other instances, the amount of DNA extracted by laboratories is far too low. You will thus need to advise the company you choose to do your DNA testing on the discreet DNA samples you plan to use and they can advise you accordingly.