Liver and Liver function tests

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LIVER & LIVER FUNCTION TESTS

LIVER &LIVER FUNCTION TESTS Uzair Mumtaz Farah ShafiqLiver is the principle organ for maintaining the bodys internal environment & of vital importance in intermediary metabolism, detoxification and the elimination of toxic substances.

Largest internal body organLargest glandLargest organ apart from skinWeighs about 1.5kgFound in the upper abdominal cavity: extends from right upper quadrant to left upper quadrant of the abdomenAttached to diaphragm byFalciform and coronary ligamentsLeft and right triangular ligaments

LIVER

Functions Of LiverHepatocytes synthesize:Plasma ProteinsCoagulation factors like Prothrombin, factors II,V,IX,X,XI,XII and XIIIPrimary bile acidsLipoproteins VLDL, HDLSynthetic FunctionsSerum Total proteinSerum albuminTotal proteins - Albumin = GlobulinProthrombin timeSerum Cholesterol

Test based on synthetic functionPrinciple:Biurets method: Photometric endpoint, colorimetric assayProteins(3P)+Alkaline Cu tartrate= Blue-Purple coloured substance.Reference Range: 65-80 g/lInterpretations:

Serum total protein:Estimation of Serum Albumin:

Principle: Bromocresol-Green methodAlbumin+ BCG Green coloured compound(citrate buffer)

Reference Range: 35-50 g/lInterpretation: Used to asses chronicity and severity of liver disease. in Chronic liver disease.

PROTHROMBIN TIME:

Synthetic dysfunction in liver disease due to of clotting factors

Reference Range: 10-14 secLiver is the only organ that has the capacity to rid the body of heme waste products.

Major heme waste product is Bilirubin, principle pigment of bile derived from breakdown of RBCs.

Hepatocytes in liver are separated by sinusoidal spaces along walls known as Kupffer cells present for detoxifying function.Excretion & Detoxification

Serum bilirubinUrine BilirubinUrine & faecal urobilinogenUrine bile saltsDye excretion tests

Test based on excretory function

Catabolism of HemeEstimated by Van den bergh reactionPrinciple: When diazotised sulfanilic acid reacts with bilirubin, it forms azobilirubin, a purple coloured product. Conjugated Bilirubin: gives colour immediately Direct positive Unconjugated Bilirubin: Gives colour after addition of methanol Indirect positive Both conjugated and Unconjugated BiphasicSerum BilirubinEhrlichs test:

Principle:Urobilinogen reacts with -dimethylamino-benzaldehyde in chloroform to form a pink coloured aldehyde complex.

Urine UrobilinogenBile salts: Hay test Principle: Bile salts have property of lowering surface tension.Hence when sulphur powder is sprinkled to urine containing bile salts, it sinks to bottom.Bile pigments: Fouchets test Principle: Bile pigments adhere to the precipitate of barium sulphate. On addition of fouchets reagent, FeCl in presence of trichloroacetic acid oxidizes yellow colour bilirubin to green colour biliverdin.Urine; Bile salts & Bile pigments

Allows important substances to reach systemic circulation and serve as a barrier to prevent toxic or harmful substancesEither bind with material to inactivate the compound or chemically modify itDrug Metabolism: Detoxification of drugs byOxidation ReductionHydrolysisHydroxylationCarboxylation Demethyaltion

Detoxification and drug metabolism

HIPPURIC ACID TEST:

Principle: Hippuric is produced in the liver when benzoic acid combines with glycine.Procedure:6gm of sodium benzoate is given to the patient.Urine is collected up to 4hrs.Hippuric excreted in urine is estimated.Normal: >4.5g of hippuric acid Abnormal: