Accuracy of DNA Paternity Testing Methods

There are two main methods which can be used for paternity DNA testing, namely, PCR (Polymerase Chain Reaction) and RFLP (Restriction Fragment Length Polymorphism). In this article we are going to be looking at these two methods, what the difference is and how they work.

Polymerase Chain Reaction testing usually involves taking a swab from the inner cheek for DNA samples. It is a faster test than RFLP and usually looks at between six and nine loci on the DNA. This test however does not provide the same degree of information as is provided by the RFLP test.

PCR DNA testing works by "amplifying" the sample DNA, or taking a small sample of DNA and then multiplying it. This is useful if only a small sample can be obtained and is also useful for working with degraded DNA. When using PCR DNA testing however the laboratory needs to be particularly careful about preventing contamination within the sample as the amplification process could tend to increase the chances of contamination.

The process of PCR DNA testing involves heating the DNA, adding primers and then cooling it so that it recombines and an enzyme reads the DNA sequence in order to create multiple copies of the DNA.

The Restriction Fragment Length Polymorphism test takes longer than the PCR test and is a slightly older method but can provide more reliable results as each loci presents more information regarding paternity. It requires a larger sample of DNA and is more likely to use blood for the DNA testing but it can also be done using a swab from the inner cheek if necessary.

The AABB report from 2004 stated that there is a decrease in the number of laboratories using the RFLP method and an increase in laboratories using the PCR method of DNA testing with PCR being used in 98.34% of the cases.

In conclusion, there are two main methods of paternity DNA testing that are mainly used today. These two methods are Polymerase Chain Reaction testing and Restriction Fragment Length Polymorphism testing. PCR testing is used in 98.34% of the DNA testing cases according to the 2004 AABB report and seems to be increasing over the older method of RFLP. PCR is a quicker method of testing and multiplies the amount of DNA material so that only small samples are needed; however this does lead to a risk of contamination. If you are going for PCR testing or ordering a DNA home test kit you should ensure that they are AABB approved and that they offer at least a 99% guarantee and test at least ten loci.