Liver function test

• Liver is the largest organ in the body, weighing about 1.2 - 1.5 kg
• Liver functions include excretory, secretory, synthetic function, detoxification, drug metabolism, and storage
• Hepatocytes secrete bile, while Kupffer cells are macrophages that remove ingested bacterial pathogens
• Laboratory tests for liver enzymes include bilirubin measurement, serum enzymes, and PT and APTT
• Alkaline Phosphate (ALP) is a non-specific enzyme that requires Magnesium & Manganese as activators
• Liver ALP, Bone ALP, and Placental PLAP are major isoenzymes of ALP
• Factors that can falsely elevate ALP levels include hemolysis, fatty meals, and storage at low temperatures
• Factors that can lead to low ALP levels include zinc deficiency and after cardiopulmonary bypass
• Increased ALP levels can be seen in conditions like osteitis deformans, obstructive jaundice, osteomalacia, rickets, and hepatitis
• Methods for analyzing ALP include electrophoresis, heat fractionation, and chemical inhibition tests
• Aspartate Aminotransferase (AST) is involved in the transfer of amino groups and is a major source in cardiac tissue and liver
• AST is used in diagnosing hepatocellular disorders and AMI, with specific elevations seen in viral hepatitis and cirrhosis
• Methods for analyzing AST levels include the Karmen Method and Reitman Frankel Method
• Alanine Aminotransferase (ALT) catalyzes the transfer of amino groups and is abundant in the liver
• ALT is more specific to liver conditions and is used in monitoring hepatitis treatment and screening blood donors
• Gamma Glutamyl Transaminase (GGT) is increased in conditions like alcoholism, acute pancreatitis, and obstructive liver disease
• 5’ Nucleotidase (5’N) is predominantly secreted by the liver and is a marker for hepatobiliary disease and infiltrative lesions of the liver
• Cholinesterase/Pseudocholinesterase (PChE) is a marker for insecticide/pesticide poisoning and decreases in the presence of disorders
• Acid Phosphatase (ACP) is a prostatic enzyme that is useful for rape cases and metastatic prostatic carcinoma
• ACP is increased in conditions like prostatic carcinoma, breast, lung, and thyroid carcinoma, Gaucher’s disease, and Neimann pick disease
• ACP methods include the Bodansky method, King-Armstrong, Bessey-Lowry-Brock, Roy and Hillman, and Babson, Read and Philips
• Alk phosphatase requires activators, what are these?

  Magnesium and manganese
• Alk phosphatase normally elevated in

  Osteoblastic children

  geriatric

  normal pregnancy (16-20 wks)
• major isoenzyme of Alk phosphatase

  liver alp

  bone alp

  placental alp
• it is useful tumor marker in serum and cf for most germ cell tumors; CSF Levels of PLAP are of diagnostic value in differentiating pinealoma or germ cell tumor

  placental alp
• FALSELY ELEVATED ALP:

  *Hemolysis and Diet (fatty meals)

  * Storage to low temp (4 C)
• LOW ALP LEVELS:

  Zinc deficiency

  after BT/ cardiopulmonary bypass
• • INCREASED ALP LEVELS:

  Osteitis deformans

  obstructive jaundice

  osteomalacia

  rickets

  osteosarcoma

  sprue

  hyperthyroidism

  hepatitis and cirrhosis
• methods used in alp

  electrophoresis

  heat fractionation/ stability test

  chemical inhibition

  bowers and mc comb/ Szasz modification
• bone alp

  inhibited by urea

  lost at 65 degrees celcius for 10 mins
• placental alp

  most heat stable

  resist at 65 deg celc for 30 mins

  inhibited by phenylalanine
• AST/ SGOT isoenzyme

  Cytoplasmic asts

  mitocondrial ast (predominant in serum)
• 2 cells in the liver

  kupffer cells & hepatocytes