Hi all,
I need support in calculating the analytical sensitivity of molecular assay ( detection of DNA) for detection of an bacterial infection from oral swab samples. Usually we spike various dilutions of pure culture suspension to the oral swabs collected form healthy volunteers and perform the assay.
For example, if we spike 10ul of 105 CFU/ml of Pure culture suspension to the oral swab, perform the DNA extraction and elute the DNA in 200ul of buffer, use 5ul of template DNA for 20ul PCR reaction, What will be the CFU equivalents in the 20ul reaction?
If you start with 105 CFU/ml and use 10ul, that is 103 CFU. Assuming 100% recovery, you put that 103 CFU into 200 ul and use 5 ul of it for the assay. So 1000 x 5 / 200 = 25 CFU equivalents in the PCR reaction.
Thankyou Michael.
Now I am confident that my calculations are right.
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