>>No, that's a magic number.
>>
>>The constant needs to be defined earlier
>>

>>const short maxAdmissionDays = 1;
>>DateTime admission_end = this.dtScan.Date.AddDays(Math.Max(admissions, maxAdmissionDays).AddSeconds(-1);
>>

>>
>Hmm, is it good practice? I can probably use this idea (the constant name should be min, though).
>
>Thanks again.
>
>Also, where and how should I declare it? At the top of the class code?

One thing to bear in mind:

If the constant will be used in different DLL's then changing the constant and re-compiling the DLL where it is declared will leave the old value in other DLLs.
Better to use 'public static readonly' - that way other DLLs will pick up the new value.