What is the best data type to store laboratory results in my Sql server and entity framework?

Question

I have a field for storing laboratory results but i cannot decide which data-type i should chose. The most important thing for me is that i do not want any automatic Decimal Conversion. I need to have the following “ what the user enter ,, is what will be saved in the database and it will be what he sees later”.

The laboratory results can varies in their format, such as:-
-    50.12
-    18000000.2452818
-     - 30.56
-    90

So i cannot  determine which datatype to use either ; decimal, float, double or even another data-type. BARING IN MIND THAT I AM USING THESE VALUES IN SOME COMPARISONS (TO SEE IF THE VALUE IS WITHIN OR EXCEED A RANGE)AND I MIGHT USE THEM IN SOME ARITHMATIC OPERATION
BR

Answer 1

http://msdn.microsoft.com/en-us/library/ms187912.aspx