This chapter provides detail description of biochemistry of medical laboratory techniques. Glucose, glucose tolerance test, urea, creatinine, bilirubin, cholesterol, triglycerides, total proteins, albumin, ceruloplasmin, cereberospinal fluid proteins, uric acid, homocystine, lactate, pyruvate, thiobarbituric acid reactive substances, glutathione, sodium, potassium, chloride, calcium, phosphorus, irin, iron binding capacity, vitamin A, vitamin E, vitamin C, SGOT, SGPT, alkaline phosphatase, acid phosphatse, ACE, lactate dehydrogenase, glucose -6-phosphate dehydrogenase, amylase and OAT etc. are described in detail with the help of excellent illustrations. 1 to 2 references are given at the end of each topic for further reading. 20 tables are included to highlight standard protocols of different techniques.