To obtain the reduction potential as a function of the measured concentrations of the redox-active species in solution, it is necessary to express the activities as a function of the concentrations.
Given that the chemical activity denoted here by { } is the product of the activity coefficient γ by the concentration denoted by [ ]: a = γ·C, here expressed as {X} = γ [X] and {X} = (γ) [X] and  replacing the logarithm of a product by the sum of the logarithms (i.e., log (a·b) = log a + log b), the log of the reaction quotient () (without {H} already isolated apart in the last term as h pH) expressed here above with activities { } becomes:
It allows to reorganize the Nernst equation as:
Where  is the formal standard potential independent of pH including the activity coefficients.
Combining  directly with the last term depending on pH gives:
For a pH = 7:
So,
It is therefore important to know to what exact definition does refer the value of a reduction potential for a given biochemical redox process reported at pH = 7, and to correctly understand the relationship used.
Is it simply: 
*  calculated at pH 7 (with or without corrections for the activity coefficients), 
* , a formal standard reduction potential including the activity coefficients but no pH calculations, or, is it, 
* , an apparent formal standard reduction potential at pH 7 in given conditions and also depending on the ratio .
This requires thus to dispose of a clear definition of the considered reduction potential, and of a sufficiently detailed description of the conditions in which it is valid, along with a complete expression of the corresponding Nernst equation. Were also the reported values only derived from thermodynamic calculations, or determined from experimental measurements and under what specific conditions? Without being able to correctly answering these questions, mixing data from different sources without appropriate conversion can lead to errors and confusion.