Liver Function Tests (LFTs) Flashcards Preview

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Flashcards in Liver Function Tests (LFTs) Deck (21):
1

Aminotransferases:

Acute Hepatocellular Injury
Injured cells release Aspartate & Alanine
Aminotransferases (AST & ALT)

2

ALT > AST b/c

↑ AST with muscle/RBC injury

3

Viral Hepatitis =

↑ ALT

4

Alcohol Hepatitis =

↑ AST (AST in mitochondria)

5

Alkaline Phosphatase:

Bile Duct Enzyme: Intrahepatic/extrahepatic injury/obstruction
===> Marker of Bile Duct Obstruction

6

Alkaline Phosphatase Level correlates with

↑ synthesis

7

Alkaline Phosphatase Isoenzymes:

Gut, Bone (cancer metastasis)

8

Alkaline Phosphatase Pregnancy =

↑ Alk Phosphatase in placenta

9

Gamma Glutamyl Transferase (GGT):

↑ GGT with biliary obstruction; back up Alk-P
because Alk-P can be from other location
===> Marker of Bile Duct Obstruction

10

Gamma Glutamyl Transferase (GGT) Elevated with drugs

(Phenytoin)

11

Gamma Glutamyl Transferase (GGT) Elevated with ethanol =

Good test for abuse
So alcohol ==> ↑AST + ↑GGT

12

Cholglycine:

Serum Bile Salt
• Correlates with cholestasis
• Used to distinguish causative agent of extreme
pruritis (intrinsic skin lesion vs. other)

13

Bilirubin Levels represent:

Bilirubin Levels represent measure of hepatic clearance / excretory function; ↑ with impaired liver clearance

14

Ammonia:

Detoxifified in liver via Urea Cycle & Glutamine Synthetase Reaction

15

Synthetic Capacity Prothrombin Time:

↑PT when CF I, II, V, VII, X are deficient (Vit K Definition)

16

Synthetic Capacity Albumin:

Rapidly changes with acute illness
Cirrhosis (chronic disease) ==> ↓albumin

17

LFTs Scores
Child Pugh Score:

Incorporates Albumin, Bilirubin, Ascites, Encephalopathy, & PT
• Prognosis before portal-systemic shunt

18

LFTs Scores
Model of End Stage Liver Disease (MELD):

Incorporates INR, Bilirubin, Creatinine

19

Bilirubin Metabolism

1. Splenic (RES) macrophages eat senescent RBCs ---> recycle globin + iron ===> UCB (lipid soluble)
2. UCB binds with albumin in blood
3. UCB (lipid soluble) taken up by hepatocytes
4. UCB glucorinidation ---> CB (water soluble)
5. CB enters duodenum via common bile duct ---> converted to urobilinogen via intestinal bacteria
6. Urobilinogen excreted in stool, urine or reabsorbed by liver

20

Jaundice =

↑UCB +/- CB

21

Extravascular Hemolysis =

↑UCB ==> ↑Everything