Liver function tests xiaoli ( LFTs ). Review: Liver ïƒ The liver is the largest organ in...

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Transcript of Liver function tests xiaoli ( LFTs ). Review: Liver ïƒ The liver is the largest organ in...

  • Slide 1
  • Liver function tests xiaoli ( LFTs )
  • Slide 2
  • Review: Liver The liver is the largest organ in the body It is located below the diaphragm in the right upper quadrant of the abdominal cavity and extended approximately from the right 5th rib to the lower border of the rib cage.
  • Slide 3
  • The liver is separated into a right and left lobe, separated by the falciform ligament. The right is much larger than the left.
  • Slide 4
  • The liver performs an astonishingly large number of tasks that impact all body systems. Liver have two channels that can supply and oxygen nutriment : hepatic artery and hepatic portal vein. The corresponding channels is hepatic vein and bile ducts.
  • Slide 5
  • The working cells of the liver are known as hepatocytes, which have a unique capacity to reproduce in response to liver injury. Liver regeneration can occur after surgical removal of a portion of the liver or after injuries that destroy parts of the liver. Although the liver's ability to react to damage and repair itself is remarkable, repetitive insults can produce liver failure and death.
  • Slide 6
  • Functions of liver Excretory function: bile pigments, bile salts and cholesterol are excreted in bile into intestine. Metabolic function: liver actively participates in carbohydrate, lipid, protein, mineral and vitamin metabolisms. Hematological function: liver is also produces clotting factors like factor V, VII. Fibrinogen involved in blood coagulation is also synthesized in liver. It synthesize plasma proteins and destruction of erythrocytes.
  • Slide 7
  • Storage functions: glycogen, vitamins A, D and B12,and trace element iron are stored in liver. Protective functions and detoxification: Ammonia is detoxified to urea. kupffer cells of liver perform phagocytosis to eliminate foreign compounds. Liver is responsible for the metabolism of xenobiotic.
  • Slide 8
  • Liver function tests ( LFTs )
  • Slide 9
  • What is Purpose of LFTs? LFTs alone do not give the physician full information, but used in combination with a careful history, physical examination (particularly ultrasound and CT Scanning), can contribute to making an accurate diagnosis of the specific liver disorder. Different tests will show abnormalities in response to liver inflammation liver injury due to drugs, alcohol, toxins, viruses Liver malfunction due to blockage of the flow of bile Liver cancers
  • Slide 10
  • LFTs are divided into true tests of liver function, such as serum albumin, bilirubin, and protime, tests that are indicators of liver injury or biliary tract disease.
  • Slide 11
  • Classification of liver functions test Classified based on the major functions of liver: EExcretion: Measurement of bile pigments, bile salts. SSerum enzymes: Transaminase (ALT, AST), alkaline phosphate(ALP), 5-nucleotidase, LDH isoenzyme. SSynthetic function: Prothrombin time, serum albumin. MMetabolic capacity: Galactose tolerance and antipyrine clearance DDetoxification :
  • Slide 12
  • 1. Excretion : Bilirubin Bilirubin is the main bile pigment that is formed from the breakdown of heme in red blood cells. The broken down heme travels to the liver, where it is secreted into the bile by the liver.
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  • via bile duct to intestines Stercobilin excreted in feces Urobilinogen formed by bacteria KIDNEY Urobilin excreted in urine BLOOD CELLS CO Biliverdin IX Heme oxygenase O2O2 Bilirubin (water-insoluble) NADP + NADPH Biliverdin reductase Heme Globin Hemoglobin reabsorbed into blood LIVER Bilirubin diglucuronide (water-soluble) 2 UDP-glucuronic acid Bilirubin (water-insoluble) via blood to the liver INTESTINE Fig. 2 metabolism of bilirubin
  • Slide 14
  • A. indirect bilirubin (normal value = 0.3 - 1.2 mg/dl) 1. serum bilirubin: B. direct bilirubin (normal value 0.4 mg/dl) C. total bilirubin Normal value for = 0.3- 1.2 mg/dl. Normally, a small amount of bilirubin circulates in the blood. Serum bilirubin is considered a true test of liver function, as it reflects the liver's ability to take up, process, and secrete bilirubin into the bile.
  • Slide 15
  • Direct Bilirubin + Diazotized Sulfanilic Acid Azobilirubin (Redish purple) total bilirubin + dimethylsulfoxide(DMSO)+methanol +diazotized sulfanilic acid to form azobilirubin. Indirect bilirubin react with diazotized sulfanilic acid after addition of methanol. The absorbance of the reaction mixture at 555 nm is directly proportional to the concentration of direct bilirubin. VD Bergh reaction
  • Slide 16
  • H H H CH 2 CO N CH O N CH 2 N H CH N O M M M M V V CH 2 CO O O OH HO COOH OH O HOOC OH O
  • Slide 17
  • indirect bilirubin direct bilirubin Binding with Glucuronic acidno yes Reacting with the diazo reagent Slow and indirect Rapid and direct solubility in watersmalllarge Discharged via kidneynoyes Pass through the membrane of cell yesno Difference of two bilirubins
  • Slide 18
  • A. urobilinogen : Conjugated bilirubin is excreted via bile salts to intestine. Bacteria in the intestine break down bilirubin to urobilinogen for excretion in the feces (normal value for fecal urobilinogen = 40 - 280 mg/day) 2. urine(/faeces) Normally there are mere traces of urobilinogen in the urine. average is 0.64mg, maximum normal 4mg/24hours. B. Urobilin Urobilin is the final product of oxidation of urobilinogen by oxygen in air. The amount change with the amount of urobilinogen excretion.
  • Slide 19
  • B. bilirubinurine: Bilirubin is not normally present in urine and faese since bacteria in intestine reduce it to urobilinogen. The kidneys do not filter unconjugated bilirubin because of its avid binding to albumin. conjugated bilirubin can pass through glomerular filter. Bilirubin is found in the urine in obstructive jaundice due to various causes and in cholestasis. Note: Bilirubin in the urine may be detected even before clinical jaundice is noted.
  • Slide 20
  • Who is a candidate for the test? Bilirubin is used to diagnosis of jaundice. Abnormal bilirubin levels can be found in many disorders, including: blocked bile ducts, cirrhosis, hepatitis and other liver diseases or immature liver development in newborns. Hemolytic Jaundice Hepatic Jaundice Obstructive jaundice ( Cholestasis) Congenital Jaundice
  • Slide 21
  • SampleIndicesNormalHemolytic Jaundice Hepatic Jaundice Obstructive Jaundice Serum Total Bil 1mg/dl 1mg/dl Direct Bil 0 0.8mg/dl Indirect Bil 1mg/dl Urine Colornormaldeeperdeep Bilirubin UrobilinogenA littleuncertain UrobilinA littleuncertain Stool Colornormaldeeperlighter or normal Argilous (complete obstruction)
  • Slide 22
  • 2. Serum enzymes A large number of enzyme estimations are available which are used to ascertain liver function. They are be divided into two groups: I: most commonly and routinely done in the laboratory. serum transaminase(ALT/AST) serum alkaline phosphate(ALP) II: not routinely done in the laboratory.
  • Slide 23
  • Alanine transaminase (ALT) ALT or sGPT (serum glutamate pyruvate transaminase)GPT
  • Slide 24
  • Aspartate aminotransferase (AST) AST or sGOT (serum glutamate oxaloacetate transaminase) GOT
  • Slide 25
  • organ GOTGPT heart 156000 7100 liver 142000 44000 skeletal 99000 4800 kidney 9100019000 organ GOT GPT pancrease spleen lung serum 28000 2000 14000 1200 10000700 2016 GPT: Normal range: 2-59 U/L GOT: Normal range: 10-34 U/L
  • Slide 26
  • Elevated levels of GPT may indicate : alcoholic liver disease cancer of the liver cholestasis or congestion of the bile ducts cirrhosis or scarring of the liver with loss of function death of liver tissue Hepatitis or inflammation of the liver noncancerous tumor of the liver use of medicines or drugs toxic to the liver Therefore, when the liver is injured, GPT is released into the bloodstream.
  • Slide 27
  • GOT also reflects damage to the hepatic cells and is less specific for liver disease. It can also be released with heart, muscle and brain disorders. Therefore, this test may be ordered to help diagnose various heart, muscle or brain disorders, such as a myocardial infarct (heart attack).
  • Slide 28
  • Elevated levels of GOT may indicate : acute hemolytic anemia, acute pancreatitis or inflammation of the pancreas. acute renal failure or loss of kidney function. cirrhosis of the liver. Hepatitis heart attack primary muscle disease recent surgery severe burns muscle injury
  • Slide 29
  • normally: GPT is normal, GOT is normal, GPT/GOT is about 1.15. Virus hepatitis: GPT, GOT is normal,GPT/GOT 1,even more than 2.5 chronic hepatitis : GPT,GOT GPT/GOT is about 1. Liver cancer, cirrhosis, Alcohol-induced hepatitis: GPT,GOT < 1, about 0.6~0.7. Accute myocardial infarct :< 1 Although GOT is not a specific for liver as the GPT, ratios between GPT and GOT are useful to physicians in assessing the etiology of liver enzyme abnormalities.
  • Slide 30
  • GPT and GOT is in the different distribution of the hepatocytes. GPT exists primarily in the cytoplasm of liver cell. if there is a slight liver cell damage, GPT firstly leak into the bloodstream, so that the serum GPT increased. The GOT mainly in the "mitochondriaof liver cells, the m