non-standard samples does not always guarantee that a DNA profile obtained. While for the buccal swabs can not get DNA, as in cases where the smear was not done properly or else mold grows swabs due to wet conditions of storage, general problems with these samples are usually less than 2%. Therefore, depending on the nature of the sample, not usually associated with a high probability, medium or low success in extracting DNA from each sample type (in some cases provides a percentage chance of success).
High (80%)For samples such as fresh blood stains or hairs with roots that, by a qualified DNA laboratory experience, is considered relatively simple DNA extraction. In such cases, provided that the sample was properly handled, both during collection and delivery to the laboratory, you can expect a high probability of success in extracting DNA.
Half (50% -60%): For samples such as cigarette butts, toothbrush or the success rate is influenced by a number of variables including face intensive use of light and / or storage conditions , etc. So the butt of a great smoked cigarettes at an ashtray at home is more likely to result in a successful DNA extraction lightly smoked a cigarette that has been lying in the street and exposed to atmospheric agents (rain, for example).
Under (20% - 30%) for samples such as teeth or bone, where DNA extraction is a process that consumes relatively difficult and time, these usually need to be managed by a highly specialized laboratory. In such cases, the person should consult with the first laboratory to check your level of experience, if they accept the sample and cost.
The above classification is however only a guideline, since as we have seen is not only the type of sample that is important, but also other variables that can influence, such as:
1. Poor storage conditions (for example, a damp environment, extreme heat, etc.)
2. Poor sample handling (possible contamination with DNA from other soil or touching the sample)
3. Not enough DNA present (eg heavily used toothbrush against used only once)
It is also important to note that the rate of success will depend largely on the ability of the laboratory performing the test. Not all laboratories that can perform DNA paternity testing with normal samples are able to obtain DNA from a wide variety of other media. The most difficult of the media (eg, teeth and bones), the greater the expertise and experience needed to increase the chance of a successful DNA extraction.
Finally, it is also important to note that non-standard samples, there is always the risk that the extraction will not work. So anyone considering the submission of the sample, especially where there may be a limited sample available (for example, a person has died) should take this into account. Selection of an experienced laboratory (possibly forensic specialist) will help minimize this risk.