Liver Function Test Flashcards
Portal triad
portal vein
hepatic artery
bile duct
cholesterol to cholesteryl esters via
lecithin-cholesterol acyl transferase or LCAT reaction
Oxidation of drugs and other toxic compounds or xenobiotics via
the cytochrome P450 system
Oxidation of alcohol
1.alcohol and acetaldehyde dehydrogenases
2. microsomal ethanol oxidizing system (MEOS)
alternate pathway of ethanol metabolism that occurs in the smooth endoplasmic reticulum in the oxidation of ethanol to acetaldehyde.
enzyme used in synthesis of creatine
guanidoacetate…. which is used to produce creatine phosphate, mainly in muscle and brain
the liver stores?
glycogen,
vitamin A,
vitamin B12
iron
enzyme needed to convert heme to biliverdin
heme oxygenase
enzyme needed to convert biliverdin to bilirubin
biliverdin reductase
What is the immediate precursor of bilirubin?
urobilinogen
other name for conjugated bilirubin
bilirubin diglucuronide
What enzyme system is responsible in the conjugation of bilirubin?
uridine diphosphate glucuronyltransferase
(UDG)
Oxidation of urobilinogen by microorganisms will produce
urobilin
other name for free bilirubin
non-polar bilirubin
Unconjugated bilirubin
Indirect bilirubin
hemobilirubin
hemolytic bilirubin
other name for Conjugated bilirubin
Polar bilirubin
Direct bilirubin
Cholebilirubin
Cholestatic bilirubin
FACTORS AFFECTING INTERPRETATION OF PLASMA LEVELS OF “LIVER” ENZYMES
age
gender
race
food ingestion
body mass index
exercise
diurnal variation
CLASSIFICATON OF LIVER FUNCTION TESTS
-Excretory Function Tests
✅Test for urobilinogen and other bilirubin pigments in the urine and feces
✅Icterus Index
✅Dye excretion tests (BSP, ICG) Serum bilirubin
CLASSIFICATON OF LIVER FUNCTION TESTS
–Metabolic Function Tests
✅Carbohydrate metabolism Galactose tolerance test
✅OGTT
✅Protein metabolism
✅TP, A/G ratio
✅Cephalin cholesterol flocculation test
✅Thymol turbidity test (Shank & Hoagland; MacLagan) Hippuric acid test
✅Lipid metabolism
Enzyme Tests
● ALT
● AST
● AST/ALT (De Ritis ratio)
● ALP
● GGT
● 5’-NT
● LAP
● LDH
● ICD
● OCT
(10)
Tests for Bilirubin
✅Evelyn- Malloy
✅Jendrassik and Grof Anino,
✅Ducci & Watson
✅Stoner & Wiseberg
✅Modified Michaelson
✅Thamhauser & Anderson
✅Alkaline methanolysis
✅Icterus index
Side note:
TB, DB and IB
✅Unlike DB, IB is insoluble in deionized water and dilute HCl.
✅IB must first be mixed with methanol or caffeine-sodium benzoate to solubilize it before one can proceed with the diazo reaction.
✅Because of these properties, TB and DB are always chemically analyzed, and the IB fraction is calculated from the difference between the TB and DB values.
used as dissociating agent (coupling promoter) to measure the total bilirubin in Evelyn-Malloy Method
Methanol
what buffer is used Jendrassik-Grof Method
Sodium acetate
what method
●The diazotized product (bilirubin-diazotized sulfanilic acid) has a red to reddish-purple color in an acid pH (HCl).
Evelyn-Malloy Method
Evelyn-Malloy Method product has an absorption maximum at ___ nm?
560 nm
what coupling accelerator is used Jendrassik-Grof Method ???
caffeine sodium benzoate
In Jendrassik-Grof Method,, The diazotization is terminated by the addition of __??
ascorbic acid
in Jendrassik-Grof Method,, the pink azobilirubin is then converted to a____?
🔵💙
Blue Azobilirubin
What method uses a strong alkaline tartrate solution, the pink azobilirubin is then converted to a blue azobilirubin.
Jendrassik-Grof Method
Side note:
As unconjugated bilirubin circulates through the liver, hepatocytes perform the following functions:
✅ Uptake of bilirubin from the circulation
✅ Enzymatic conjugation as bilirubin
glucuronides
✅ Transport and excretion of conjugated bilirubin into the bile for elimination from the body
Side note:
Congenital defects in each of these metabolic steps are recognized clinically:
1️⃣ Defect in uptake?
2️⃣ Defect in hepatic glucuronyl transferase
3️⃣ Defect in transport extracellularly
1️⃣ Defect in uptake
—- (GILBERT SYNDROME)
2️⃣ Defect in hepatic glucuronyl transferase
—- (CRIGLER NAJJAR SYNDROME)
3️⃣ Defect in transport extracellularly
—- (DUBIN-JOHNSON SYNDROME)
SERUM BILIRUBIN reference range:
Total:
Direct
✅Total 0.3-1.1 mg/dl
✅Direct 0.1-0.4 mg/dl
SERUM BILIRUBIN Conversion factor:
✅17.1 (mg/dl to μmol/L)
CAUSES OF HYPERBILIRUBINEMIA
● Increased unconjugated bilirubin (HEMOLYSIS)
● Red cell degradation
● Defective hepatocellular uptake or conjugation
Increased unconjugated bilirubin
– ● Hemolysis
● Hemoglobinopathies
● Spherocytosis
● G-6-PD deficiency
● Autoimmunity
● Hemolytic transfusion reaction
– ● Red cell degradation
● Hemorrhage into soft tissue or body cavities
● Inefficient erythropoiesis
● Pernicious anemia
– ● Defective hepatocellular uptake or conjugation
● Viral hepatitis
● Hereditary enzyme deficiencies
● Hepatic immaturity in newborns
Increased total bilirubin due to increased direct bilirubin suggests
a. hemolytic jaundice
b. neonatal jaundice
c. Crigler-Najjar syndrome
d. obstructive jaundice
d. obstructive jaundice
Mesobilirubinogen, urobilinogen and stercobilinogen are collectively known as
a. urobilinogen b. urobilins
c. bilirubin products d. mesobilirubins
b. urobilins
Complete obstruction of the common bile duct would yield all of the following results except
a. negative urine urobilinogen
b. negative fecal urobilinogen and urobilin
c. negative urine bilirubin
d. passage of acholic stools
b. negative fecal urobilinogen and urobilin
Which of the following chracterizes Crigler-Najjar syndrome?
a. inability to transport bilirubin
b. deficiency of enzyme required for bilirubin conjugation
c. inability to transport bile to the intestine
d. necrotic liver damage
b. deficiency of enzyme required for bilirubin conjugation
The inability to transport bilirubin from the sinusoidal membrane to the hepatocyte is characteristic of
a. carcinoma of common bile duct
b. Crigler-Najjar syndrome
c. Dubin-Johnson syndrome
d. Gilbert’s syndrome
c. Dubin-Johnson syndrome
Dubin-Johnson is characterized by all of the following except
a. Impaired excretion of bilirubin into bile
b. Normal hepatic uptake of bilirubin
c. Inability to conjugate bilirubin
d. Increased urine bilirubin
b. Normal hepatic uptake of bilirubin
(GENETIC DISEASES OF THE LIVER)
– Alpha1-antitrypsin deficiency (AAT)
✅ what gene
✅ what protein product
✅Gene: SERPIN1 (Pi)
✅Protein product: Alpha1-antitrypsin
are microscopically centered around portal triads, which are interconnecting loose bands that contain branches of the portal vein, hepatic artery, and bile duct.
lobules/acini
Side note:
✍️Hepatic Anatomical Features
Has a dual blood supply of oxygen and nutrients amounting to 1500 mL per minute approximately 80% enters from the portal vein and 20% from hepatic artery
The line that separates the left and right hepatic lobe?
Falciform ligament
