Protein C Antigen and Functional

There are two types of protein C deficiencies. In type 1, a patient does not produce enough protein C. In type 2, a patient produces defective protein C, but in normal amounts. Protein C, Total Antigen, only measures the amount of protein C and thus does not detect a type 2 deficiency. Protein C, Functional, measures the amount of functioning protein C and should be used instead.