Important liver function tests are: (1) Serum bilirubin; (2) Urine bile pigments, bile salts, urobilinogen; (3) Alanine amino transferase; (4) Alkaline phosphatase; (5) Serum total proteins; (6) Serum albumin. Bilirubin is estimated by van den Bergh reaction. Normal serum does not give a positive van den Bergh reaction. When bilirubin is conjugated, the purple color is produced immediately on mixing with the reagent, the response is said to be van den Bergh direct positive. When the bilirubin is unconjugated, the color is obtained only when alcohol is added, and this response is known as indirect positive. The most common cause for hepatocellular jaundice is the infection with hepatitis viruses (viral hepatitis). High levels of alkaline phosphatase (ALP) are noticed in patients with cholestasis or hepatic carcinoma. The GFR of a person with 70 kg body weight is 120–125 ml per minute. Large quantities (upto a few grams per day) of albumin are lost in urine in nephrosis. Microalbuminuria is seen as a complication of diabetes mellitus and hypertension. Ketonuria may be detected by Rothera’s test. Clearance is defined as the quantity of blood or plasma completely cleared of a substance per unit time and is expressed as milliliter per minute. Inulin is neither absorbed nor secreted by the tubules. Therefore, inulin clearance is a measure of GFR. Important renal clearance tests are: (1) Renal clearance tests (creatinine and urea); (2) Proteinuria; (3) Concentration and dilution tests. Creatinine clearance test is simple to perform and easy to interpret. Creatinine co-efficient is the urinary creatinine expressed in mg/kg body weight. The value is elevated in muscular dystrophy. Normal range is 20–28 mg/kg for males and 15–21 mg/kg for females. Maximum urea clearance is found to be 75 ml/minute in normal.