This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
In renal disease albumin is the first protein to appear in urine because: 
Select and explain. 
A. Of its high concentration in plasma, B. It has molecular weight slightly greater than the molecules normally getting filtered, C. Of high Albumin: Globulin ratio, D. Tubular epithelial cells are sensitive to albumin
B: It has molecular weight slightly greater than the molecules normally getting filtered
Answer: B: It has molecular weight slightly greater than the molecules normally getting filtered 
Explanation: In a healthy renal and urinary tract system the urine contain no or trace amount of proteins. One third of this protein is mainly albumin. The 3 main plasma proteins are albumin, globulin and fibrinogen. Of these albumin has the lowest molecular weight of 69,000, globulins has molecular weight of 1,40,000. Since albumin is filtered more readily than globulins it is usually seen abundantly in the urine in pathologic conditions. Normally, glomeruli prevent the passage of protein from the blood to the glomerular filtrate. Therefore its presence in urine is the single most impoant indication of renal disease. Ref: A Manual of Laboratory and Diagnostic Tests By Frances Talaska Fischbach, page 212, Essentials of Pathophysiology: Concepts of Altered Health States By Carol Poh page 165.