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DNA in unusual samples

Laboratorio de ciencia

Currently the easiest and most efficient way to obtain DNA for a paternity test is to obtain oral epithelial cells by swabbing, some laboratories still take blood samples that are placed on FTA cards. However, many times it is not possible to obtain these samples and it is necessary to access the DNA using other samples such as: hair, nails, toothbrushes, semen, etc. These types of samples are called unusual samples.


Depending on the type of sample, it will be possible to know how easy it is to obtain DNA. For this, it has been classified into categories according to the complexity of obtaining DNA and the price of the test varies.

Category A
90% or more chance of obtaining DNA

  • bone marrow

  • Blood or filter paper

  • Semen

Category B
60-90% chance of getting DNA

  • blood stain on cloth

  • finger nails/nail clipping

  • diabetic test strips

  • Tissue (muscles, organs); not embalmed

  • swab with opium wax

  • deceased fetus

  • semen stain on cloth

  • Umbilical cord

Category C
60% or less chance of getting DNA

  • hair with root

  • Razor

  • cigarette butt

  • chewing gum/chewing gum

  • Mucous membrane

  • Condom

  • Tissue sample; paraffin embedded

  • Toothbrush

  • soda can/glass cup/plastic container or container

  • tampon/pad

  • straw

  • envelope flap

  • embalmed tissues

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