Milligram per cent

Milligram per cent is a traditional symbol used to denote a unit of measure of concentration.  The traditional use of the 'mg%' symbol was meant to indicate the mass (in milligrams) of that chemical in 100 milliliters of solution (e.g., blood). 
The meaning of the symbol 'percent' is  , therefore the accurate meaning of the notation 'mg%' is 'mg/100', which is a unit of mass, not a concentration.  Therefore, for dimensional analysis purposes, when denoting a concentration of mass divided by volume, it has largely been replaced by units such as 'mg/dL' or the International System of Units equivalent. 

For example, a plasma ethanol concentration incorrectly denoted as 0.1 mg% can be written as '0.1 mg/dL' (or '1 mg/L', etc.)  meaning a mass of 0.1 milligrams of ethyl alcohol per 100 milliliter volume of plasma. 

See also 
 Gram per liter
 cf.  ppm

References

Category:Chemical properties
Category:Physiology
Category:Nephrology
Category:Blood tests