Comparison of three DNA extraction methods from whole blood samples for use in resource-limited settings

DNA extraction from whole blood is a critical step in molecular biology and diagnostic applications. The choice of extraction method determines DNA yield and purity, which directly influence the quality of downstream analyses. While commercial kits are widely used for their simplicity, they remain costly and often inaccessible in resource-limited laboratories. Classical salting-out protocols, although inexpensive, vary in performance depending on modifications applied. Therefore, identifying an optimal method that balances yield, purity, cost, and usability is essential for ensuring reliable molecular testing in low-resource environments.

This study compared three genomic DNA extraction methods: a modified salting-out protocol, a simple non-enzymatic salting-out method, and a commercial silica column-based kit. Whole blood from a single healthy donor (biological n = 1) was processed with eight independent extraction replicates per method. DNA yield and purity were assessed by spectrophotometry, and PCR suitability was evaluated under standardized DNA input conditions. The modified salting-out method produced the highest mean DNA yield (76.12 ± 31.43 ng/μL, p < 0.05), whereas the simple salting-out method showed the most favorable purity ratios (A260/280 = 1.81 ± 0.14; A260/230 = 1.47 ± 0.26). All three methods generated amplifiable DNA. The commercial kit showed the most favorable workflow characteristics and the highest melt-peak AUC used here as a supportive indicator of amplification signal.

Commercial silica column kits offer clear advantages in speed and ease of use but remain constrained by cost in many laboratories. Under the conditions tested, the modified salting-out method provided the highest DNA yield at minimal expense, whereas the simple salting-out method showed better spectrophotometric purity. These findings support salting-out procedures as practical low-cost alternatives for routine genomic DNA extraction in resource-limited laboratories, provided that priority endpoints (yield, purity, or workflow simplicity) are clearly defined.