13 - Liver Function Test

Senescent RBCs

What is the main source of bilirubin?

F

T/F: Bilirubin is soluble in plasma

Albumin

This protein is responsible for carrying bilirubin in the bloodstream

B

QC: Expected total bilirubin in (1) Adults (2) Children

<0.3 mg/dL

Normal value of Direct Bilirubin in adults?

0.1-1 mg/dL

Normal value of Indirect Bilirubin in adults?

Ligandin

Upon entry of bilirubin in the hepatocyte, what protein is responsible for transporting it to the SER for glucuronidation?

UDP-glucuronyltransferase

Enzyme that facilitates the glucuronidation of bilirubin

Multidrug Resistant Protein (MRP) transporter

Transporter that excretes bilirubin glucuronides into the canalicular system

Gilbert Syndrome

This disease is associated with a defective transport protein found in the hepatocyte

Hemolytic Anemia

This disease is associated with an overwhelming synthesis of B1 from destroyed RBCs

Dubin Johnson Syndrome

This disease is associated with a defect in the MRP which prevents secretion of bilirubin glucuronides

Crigler-Najjar Syndrome

This disease is associated with a mutation in the UDP-glucuronyltransferase

A

QC: Gilbert Syndrome will elevate (1) B1 (2) B2

A

QC: Hemolysis will elevate (1) B1 (2) B2

A

QC: Crigler-Najjar Syndrome will elevate (1) B1 (2) B2

B

QC: Dubin Johnson Syndrome will elevate (1) B1 (2) B2

B

QC: Biliary Obstruction will elevate (1) B1 (2) B2

B

QC: Septic states will elevate (1) B1 (2) B2

2.5-3 mg/dL

Jaundice is a clinical manifestation that appears at what serum bilirubin levels?

F; B2

T/F: Tea-colored urine and acholic stools are clinical manifestations associated with an increase in B1

F; Arterial

T/F: Venous levels of ammonia correlate with the severity of encephalopathy

GABA

Ammonia is able to deplete what NT?

Ammonia

This is a product of protein metabolism that, when accumulated, causes encephalopathy

CPS1

This enzyme, which is the rate limiting step of the urea cycle, metabolizes ammonia

>80%

What percentage of the liver parenchyma would have to be damaged to see reduced urea cycle enzymes and increased ammonia levels

Depletes GABA, Toxic to astrocytes, and Neutrophil dysfunction

3 Mechanisms of ammonia toxicity

B

VR: (1) Cirrhosis (2) HDL3

A

VR: (1) Cirrhosis (2) TG

A

VR: (1) Cirrhosis (2) Phospholipids

A

VR: (1) Cirrhosis (2) Lecithin

A

VR: (1) Cirrhosis (2) VLDL

B

VR: (1) Cirrhosis (2) LCAT

B

VR: (1) Cirrhosis (2) LPL

A

VR: (1) Alcoholic Liver Injury (2) HDL3

A

VR: (1) Alcoholic Liver Injury (2) Alpha protein A1

A

VR: (1) Cholestasis (2) LpX

Proteins

This is the most important/obvious derangement when there is presence of liver disease

Immunoglobulins and vWF

What 2 proteins are not synthesized in the liver?

Factor 7

This is the first protein affected with liver damage

Plasma cells

What cells produce immunoglobulins?

Endothelium and Megakaryocytes

What cells produce vWF?

Albumin

This protein is responsible for colloid osmotic pressure, blood viscosity, and buffers blood pH

Ceruloplasmin, Haptoglobulin, Prothrombin

Enumerate the alpha globulins

Haptoglobulin

This alpha globulin transports hemoglobin released by dead RBCs

Ceruloplasmin

This alpha globulin transports copper

Prothrombin

This alpha globulin promotes blood clotting

Transferrin and Complement Proteins

Enumerate the beta globulins

Transferrin

This beta globulin transports iron

Complement Proteins

This beta globulin aids in the destruction of toxins and microorganisms

Fibrinogen

This gamma globulin becomes fibrin, a major component in blood clots

B

VR: (1) Liver Damage (2) Protein Synthesis

Beta-gamma bridging

This is a characteristic finding when doing serum protein electrophoresis in a cirrhotic patient

Albumin

Decrease of this portein serves as a prognostic factor for cirrhosis

2:1

Normal Albumin:Globulin Ration

DIC

Most common coagulopathy in liver failure

F; PT due to short half life of factor 7

T/F: aPTT is affected early in liver disease due to the short half life of factor 9

Cytoplasm

What compartment of the hepatocyte does Lactic acid Dehydrogenase belong in?

Cytoplasm

What compartment of the hepatocyte does Alanine Aminotransferase belong in?

Cytoplasm

What compartment of the hepatocyte does Aspartate Aminotransferase c belong in?

Mitochondria

What compartment of the hepatocyte does Aspartate Aminotransferase m belong in?

Canaliculi

What compartment of the hepatocyte does Alkaline Phosphatase belong in?

Canaliculi

What compartment of the hepatocyte does Gamma-Glutamyl Transferase belong in?

ASTm

In alcoholism, which liver enzyme is expected to be increased?

ALP and GGT

In cholestasis and biliary obstruction, which liver enzymes are expected to be increased?

Vitamin B6

Transaminases uses what vitamin as a cofactor?

Cori cycle

ALT participates in what cycle?

Malate Shuttle

AST participates in what biochemical process?

B

QC: Half life of (1) AST (2) ALT

T

T/F: AST is found both intramitochondrial and extramitochondrial

F; Extramitochondrial only

T/F: ALT is found both intramitochondrial and extramitochondrial

Ubiquitous in body tissues

Tissue sources of AST

Primary is liver with some in the kidney

Tissue sources of ALT

2.5:1

Hepatic fraction of AST:ALT

F; 1000 UI/L

T/F: Elevation of transaminase at approximately 300 UI/L is specific for hepatocellular injury

>2:1

Describe the ratio of AST:ALT in alcoholic hepatitis

C

QC: In chronic hepatocellular injury (1) ALT (2) AST

A

QC: In acute hepatocellular injury (1) ALT (2) AST

Cardiac, Kidney, and RBCs

LDH1 and LDH2 is found in what organs?

Lungs and Lymphocytes

LDH3 is found in what organs?

Liver and Skeletal Muscle

LDH4 and LDH5 is found in what organs?

Space Occupying Lesion

Elevated LDH and ALP with normal transaminases could indicate?

Liver and Bone

Majority of ALP is found in what organs?

Kidney, Intestine, Placenta, Germinal Tissues

Tissue-specific ALP is found in?

F

T/F: Rise in ALP correlates with the degree of obstruction

A

VR: (1) Pregnancy (2) ALP

Chronic cholestatis

GGT is highest during what condition?

F; ALP is non-specific while GGT is liver-specific

T/F: ALP is specific to the liver while GGT is non-specific

Alpha-fetoprotein

This protein in synthesized by embryonic hepatocytes and fetal yolk sac cells

A

VR: (1) Neural Tube defects (2) aFP

>400 ng/dL

At what amount of aFP in ng/dL indicates a high probability of HCC

Hepatitis B

This is the only type of hepatitis where the genome is made of dsDNA

ALP and GGT

In obstructive liver injury, which liver enzymes are expected to increase?

AST and ALT

In Hepatocellular liver injury, which liver enzymes are expected to increase?

T

T/F: HAV-RNA is present during the incubation period

T

T/F: Anti-HAV IgM is diagnostic of acute infection

F; Previous

T/F: Anti-HAV IgG is diagnostic of acute infection

2-3 weeks after infection

When does anti-HAV IgM usually develop?

3-6 months

How long does anti-HAV IgM persist?