A Simple and Cheap Method to Extract SARS-COV-2 Nucleic Acid from Nasopharyngeal Swab Without the Need Silica Filter Column

Abstract

Background: The COVID-19 pandemic affected different aspects of human life seriously, including health issues. Unfortunately, the process of RNA extraction using commercial kits is highly expensive. Replacement of this technique with a cheaper one may help us catch a more affordable approach. Objectives: This study aims to introduce a simple and cost-benefit procedure to extract nucleic acid from swab samples of patients infected with SARS-COV-2. Methods: All 41 positive extracted samples were extracted with three methods separately. The first method was based on the commercial kit using a silica filter column. The second method was made of ammonium acetate, sodium acetate, and alcohol as an extraction solution, and the last method was applied using only the sodium acetate and alcohol solution. Results: All samples extracted with a commercial kit based on a silica column were positive (100%) with Cts 21 ± 4.9, 21.4 ± 4.8, and 28.1 ± 1.8 for RNA-dependent RNA polymerase (RdRp), N, and RNase P genes, respectively. In the precipitation method using ammonium acetate, 40 samples were detected positive (97.5%), and the Cts were 26.3 ± 4.5, 23.6 ± 5.3, and 25.7 ± 3.5 for the above three genes, respectively. Similar to the conventional extraction method, the third method also showed positive results (97.5%) significantly. The mean CTs were 26 ± 4.3, 23 ± 5.4, and 23.7 ± 2.3, respectively. Conclusions: Our results indicated that the precipitation method using ammonium acetate, sodium acetate, and ethanol could be an alternative extraction method instead of the column-based method for SARS-COV-2 by swab samples.