A method for detecting electromagnetic waves derived from bacterial DNA, including extracting and purifying nucleic acids from a sample; diluting the extracted purified nucleic acids in an aqueous solvent; measuring a low frequency electromagnetic emission over time from the diluted extracted purified nucleic acids in an aqueous solvent; performing a signal analysis of the low frequency electromagnetic emission over time; and producing an output, based on the signal analysis, in dependence on the DNA in the sample. The DNA may be extracted from at least one of blood, feces, urine, saliva, tears, seminal fluid, sweat, seminal and vaginal fluids of a patient, or water to determine, e.g., potability. The samples may be frozen. The extracting and purifying may include diluting the sample with an aqueous buffer and mixing; degrading proteins in the diluted sample; precipitating DNA from the buffer solution; and resuspending the precipitated DNA in an aqueous solution.