Comparison of biological specimens and DNA collection methods for PCR amplification and microarray analysis.

There are several biological sources which could be used for DNA isolation and genetic testing with potential application in the clinical setting [1]. Increasingly, DNA isolated from buccal swabs and, more recently, saliva samples is under investigation for potential use in the clinical setting rather than traditional blood samples due to ease of access, storage, and transport, as well as relative comfort for participants with low cost of acquisition [1, 2]. Reports to date indicate that DNA isolated from saliva may be more reliable for genotyping by PCR and electrophoresis [3–6], whereas buccal DNA from mouth swabs has produced variable genotyping success as low as 23% [4]. However, there is a paucity of information available on the comparison of buccal and/or saliva DNA for chromosomal microarrays, a commonly used tool for genetic testing. In response to Durdiaková et al. [1], we wish to report our experience with DNA isolation using non-traditional sources such as buccal cells, saliva, and even plasma. Plasma is not intended to be a recommended source of DNA isolation other than a possible alternative for DNA isolation if peripheral blood, the more conventional source of DNA for genetic testing, is not available from an individual. Their utility in both genotyping and microarray analysis will be illustrated.