What is the most abundant class of plasma protein? Globulin Albumin Clotting factors Complement proteins Albumin (approximately 60% of total plasma protein at a concentration of about 4 g/dl) is the most abundant plasma protein. Carcinoma in situ is characterized by which changes? Cells have broken through the local basement membrane. Cells have invaded immediate surrounding tissue. Cells remain localized in the glandular or squamous cells. ...