Abstract:
Background: It is essential that methods for genomic DNA extraction techniques produce high
yield and purified DNA. Commercially available DNA extraction kits have taken over the
traditional DNA extraction techniques. However, to meet the demands of cost-effectiveness,
ready availability, safety, reliability and purity in resource-limited settings, an improved
traditional DNA extraction method which meet the above criteria is required. Aim: We therefore
evaluated the modified salting out and double salt precipitation method, against QIAamp Blood
Mini Kit. Materials and Methods: In a cross-sectional study, DNA was extracted from venous
blood of 60 suspected typhoid fever patients who visited the Komfo Anokye Teaching Hospital
diagnostics department to do laboratory investigations that required blood collection. Their
DNA was extracted using the three different methods. Spectrophotometric measurement of
the yields (ng/µl) and purities (260/280 nm) of the extracted DNA was done. PCR analysis was
performed on the DNA extracts to evaluate suitability for downstream analysis. We employed
the Mann-Whitney, Kruskal-Wallis and Bland-Altman plots for statistical comparisons. Results:
The modified double salt precipitation and enzymatic salt precipitation methods produced a
higher yield than the QIAamp Blood Mini Kit method (P<0.01 each). The yield from the double
salt precipitation method was higher than that of the enzymatic salt precipitation method
(P=0.04). The level of purity of DNA extracted from all three methods were comparable (P=0.24).
Conclusion: Our modified double salt and enzymatic salt precipitation techniques offer higher
DNA yields than the commercially available QIAamp Blood Mini Kit and with comparable
purity. We recommend the use of these modified techniques in resource-limited settings.
