SEM 1 - (CC) LIVER FUNCTION TEST 2 Flashcards
2nd liver function test
TEST MEASURING CONJUGATION AND EXCRETION FUNCTION
One of the most important functions of the liver is the excretion of endogenous and exogenous substances into the ____ or ____ such as the major heme product, ______
bile or urine ; bilirubin.
The _____ is the only organ that has the capacity to rid the body of heme waste products.
liver
hence ______ measures the capacity of the liver to conjugate and excrete.
bilirubin
the end product of hemoglobin metabolism
Bilirubin
principal pigment in bile
Bilirubin
Bilirubin is also formed from destruction of heme-containing proteins such as ______, ________, and ________
myoglobin, catalase, and cytochrome oxidase.
WHAT TYPE OF BILIRUBIN?
Water-insoluble
Non-polar bilirubin
Indirect reacting
Hemobilirubin
Slow reacting
Prehepatic bilirubin
Unconjugated Bilirubin
WHAT TYPE OF BILIRUBIN?
Water-soluble
Polar bilirubin
Direct reacting
Cholebilirubin
One minute/Prompt Bilirubin
Posthepatic bilirubin/Hepatic Bilirubin/Obstructive and Regurgitative Bilirubin
Conjugated Bilirubin
Ref Range of conjugated bilirubin
0-0.2 mg/dL (0-3 umol/L)
Ref Range of unconjugated bilirubin
0.2-0.8 mgdL (3-14 umol/L)
Ref Range of Total Bilirubin
0.2-1.0 mg/dL (3-17 umol/L)
(BILIRUBIN METABOLISM)
Red cell lysis after 120 days separates the ___ and ____
heme and globin
(BILIRUBIN METABOLISM)
heme is converted to unconjugated bilirubin in __ hours after lysis, the globin is digested to ______ and reused in the body.
3 ; amino acids
(BILIRUBIN METABOLISM)
while the iron is bound to _______ and becomes part of the iron pool in the______ and ______
transferrin ; liver and bone marrow
(BILIRUBIN METABOLISM)
The ________ is insoluble in water and the only mechanism to remove it from the plasma is through
______ in the liver.
unconjugated bilirubin ; conjugation
(BILIRUBIN METABOLISM)
To reach the site of conjugation, the hemobilirubin binds to ______ and
transport it up to the ________, followed by dissociation of the
_______ before entering the core of the liver.
albumin ; hepatic sinusoid ; hemobilirubin
(BILIRUBIN METABOLISM)
The _________ of the hepatic cell is the actual site of conjugation, and the _______ is the common isoform of UDPGT that is involved in the process. Another set of carrier proteins brings the
hemobilirubin to the SER.
smooth endoplasmic reticulum (SER) ; UDPGTIA1
(BILIRUBIN METABOLISM)
The intracellular conjugation of
________ onto two sites of the bilirubin molecule confers negative charge to it, making conjugated bilirubin soluble in _____ phase.
glucuronic acid ; aqueous
(BILIRUBIN METABOLISM)
Only small amounts of cholebilirubin circulates in blood because of minor leakage of the _______ in directions
away from the formation and excretion of bile; only _______ can enter the bile .
hepatocytes ; cholebilirubin
(BILIRUBIN METABOLISM)
______ and the early segment of the colon are the major sites of deconjugation with minimal deconjugation in the duodenum,
and the colon enzymes from the indigenous flora catalyze the process, resulting in the formation of _______, also known as the ________.
Ileum ; urobilinogen ; stercobilinogen
(BILIRUBIN METABOLISM)
______ or ______ is the oxidized form of urobilinogen which imparts stool its color;
Stercobilinogen or urobilin
(BILIRUBIN METABOLISM)
however, once the feces is exposed to air, the color of the stool turns dark due to the conversion of residual ______ to ______
urobilinogen to urobilin.
(BILIRUBIN METABOLISM)
_______ is responsible for the normal color of the urine;
Urobilin
(BILIRUBIN METABOLISM)
most of the urobilinogen is excreted in the feces as _____ while the remaining is either eliminated as _____ or _____ in the urine.
stercobilin ; urobilinogen or urobilin
conjugated bilirubin tightly bound to albumin.
Delta Bilirubin
Delta Bilirubin has longer half-life (_________) than other forms of bilirubin (_______).
12-14days ; 2-4hours
It is formed due to prolonged elevation of conjugated bilirubin in the case of biliary obstruction.
Delta Bilirubin
helps in monitoring the decline of serum bilirubin following surgical removal of gallstones.
Delta Bilirubin
Delta Bilirubin reacts with __________, specifically in the direct bilirubin assay
diazo reagent
Delta Bilirubin is not calculated on _________ (≤14 days ).
neonatal patients
Delta Bilirubin calculation and ref. range
Calculation: T B DB + IB = Delta bilirubin
Ref. Range: < 0.2 mg/dL (<3 pmol/L)
The plasma concentration of bilirubin increases upon ______ and reaches its peak on the ____ day.
birth ; 5th
Bilirubin comes from the normal lysis of the erythrocytes with less contribution from heme-containing proteins and enzymes such as myoglobin, cytochrome, and catalase.
myoglobin, cytochrome, and catalase.
Albumin binding reduces _______, restricts bilirubin’s ability to leave the _______, and inhibits it from ______ and ______ in tissues.
glomerular filtration ; vascular space ; precipitating and accumulating
Bilirubin conjugation to its water-soluble form involves the dissociation of _______, which is a necessary step in its disposal by the liver and the kidneys.
This is accomplished by _______ conjugation of the bilirubin’s propionic acid side chains.
hydrogen bonds ; glucuronic acid
The intestinal mucosa does not reabsorb conjugated bilirubin due to its __________ and _________
hydrophilicity and large molecular size
If the rate of bilirubin formation exceeds the rate of liver clearance (i.e., state of overproduction of bilirubin), there will be a rise in the bilirubin level in ______
serum.
Jaundice is also called ____ or _____
icterus or hyperbilirubinemia.
characterized by yellow discoloration of the skin, sclerae, and mucus membranes.
Jaundice
Jaundice is clinically evident when bilirubin level exceeds ________
3 mg/dL
3 classification of Jaundice or hyperbilirubinemia:
Pre-hepatic Jaundice or Hemolytic Jaundice
Post-hepatic Jaundice or Obstructive Jaundice
Hepatocellular Combined Jaundice or Hepatic Jaundice
Cause: Too much destruction of red blood cells (premature RBC lysis)
Clinical cases: Malaria, hemolytic anemia, and hemolytic disease of the newborn
Serum Bilirubin: Elevated B1
Urine Bilirubin: Negative
Urine Urobilinogen: Normal or increased
Pre-hepatic Jaundice or Hemolytic Jaundice
Cause: Failure of bile to flow or reach the intestine
Clinical cases: Cholelithiasis, bilateral pancreatic tumor, and colon parasitism
Serum Bilirubin: Elevated B2
Urine Bilirubin: Positive
Urine Urobilinogen: Decreased or Undetectable
Post-hepatic Jaundice or Obstructive Jaundice
Cause: Hepatocyte injury caused by viruses, alcohol, and parasites
Clinical cases: Cirrhosis, viral hepatitis, toxic hepatitis, and fascioliasis
Serum Bilirubin: Elevated B1 and B 2
Urine Bilirubin: Positive
Urine Urobilinogen: Decreased or Undetectable
Hepatocellular Combined Jaundice/Hepatic Jaundice
Derangements of Bilirubin Metabolism
- Gilbert’s Syndrome/Bilirubin Transport Deficit
- Crigler-Najjar Syndrome/Conjugation Deficit Syndrome
- Dubin-Johnson Syndrome/Bilirubin Excretion Deficit
- Lucey-Driscoll Syndrome/Conjugation Inhibitor Syndrome
- Rotor Syndrome/Mixed Hyperbilirubinemia
- Kernicterus: Bilirubin-Induced Brain Dysfunction
characterized by impaired cellular uptake of bilirubin
Gilbert’s Syndrome/Bilirubin Transport Deficit
Gilbert’s Syndrome/Bilirubin Transport Deficit is characterized by a molecular deficit within the gene involved in bilirubin metabolism such as the insertion of 2 bases into the promoter region of the _____ gene that encodes for UDGPT, resulting in lower transcriptional rates and diminished enzymatic activity.
UGT1A1
Gilbert’s Syndrome/Bilirubin Transport Deficit is diagnosed in _______
young adults ; 20-30 years old
In Gilbert’s Syndrome/Bilirubin Transport Deficit, affected individuals may have no symptoms but may have _________
mild icterus
In Gilbert’s Syndrome/Bilirubin Transport Deficit, the serum bilirubin is
Elevated B1 (< 3 mg/dL)
a derangement of bilirubin metabolism characterized by the absence of UDGPT
Crigler-Najjar Syndrome/Conjugation Deficit Syndrome
has been observed that multiple mutations in UGT1A1 gene, resulting in formation of dysfunctional proteins, which may lead to this abnormal condition.
Crigler-Najjar Syndrome/Conjugation Deficit Syndrome
Crigler-Najjar Syndrome/Conjugation Deficit Syndrome is common among ________ and the treatment is by ______
infants ; phototherapy
In Crigler-Najjar Syndrome/Conjugation Deficit Syndrome, the serum bilirubin is
Elevated B1
Two types of Crigler-Najjar Syndrome/Conjugation Deficit Syndrome
- Type 1 Crigler-Najjar Syndrome
- Type 2 Crigler-Najjar Syndrome
A type of Crigler-Najjar Syndrome with Absolute deficiency of the enzyme UPDGT
Type 1
In type 1 Crigler-Najjar Syndrome, there’s a _____ of B2 production
total absence
distinct feature of type 1 Crigler-Najjar Syndrome
(+) kernicterus
bile is colorless
a type of Crigler-Najjar Syndrome that is characterized by partial deficiency of UDPGT and theres a small amount of B2 is produced
Type 2 Crigler-Najjar Syndrome
associated with the blockade of the excretion of bilirubin into the canaliculi caused by a hepatocyte membrane defect
Dubin-Johnson Syndrome/Bilirubin Excretion Deficit
In Dubin-Johnson Syndrome/Bilirubin Excretion Deficit, the defect in the canalicular organic anion transport, contributes to ________, specifically the mutation in the human _____ gene.
pathogenicity ; cMOAT
Dubin-Johnson Syndrome/Bilirubin Excretion Deficit is observed with ________ and the total bilirubin level is not exceeding __mg/dL.
mild jaundice ; 5 mg/dL
distinct feature and serum bilirubin of Dubin-Johnson Syndrome/Bilirubin Excretion Deficit
Distinct feature: Intense dark pigmentation of the liver due to accumulation of lipofuscin pigment
Serum bilirubin: Elevated B2
a familial form of unconjugated hyperbilirubinemia (transient familial hyperbilirubinemia) and may be caused by a circulating inhibitor of bilirubin conjugation in the baby’s or mother’s blood
Lucey-Driscoll Syndrome/Conjugation Inhibitor Syndrome
Lucey-Driscoll Syndrome/Conjugation Inhibitor Syndrome may also be due to a genetic change in the _____ gene enhancing _______
UGT1A1 ; hyperbilirubinemia.
an autosomal recessive disease ; it is an inherited disorder where the exact cause is unknown though it may be caused by having mutations in both the SLCO1B1 and SLCO1B3 genes
Rotor Syndrome/Mixed Hyperbilirubinemia
Rotor Syndrome/Mixed Hyperbilirubinemia may also be a defect of ________ of conjugated bilirubin.
sinusoidal reuptake
serum bilirubin and distinct feature of Rotor Syndrome/Mixed Hyperbilirubinemia
Serum bilirubin: ElevatedB1 and B2 (conjugated bilirubin is prominent)
Distinct feature: (+) Porphyrinuria
a derangement of Bilirubin Metabolism that is due to immature blood brain barrier among infants and is characterized byelevated unconjugated bilirubin
Kernicterus: Bilirubin-Induced Brain Dysfunction
type of brain damage that can result from high levels of bilirubin in a baby’s blood
Kernicterus: Bilirubin-Induced Brain Dysfunction
Kernicterus: Bilirubin-Induced Brain Dysfunction can cause _____ and _____ also creates problems with ________, _______ and ________.
athetoid cerebral palsy and hearing loss.
vision and the teeth, and intellectual disabilities
When B1 rises in neonates due to deficient ________, it cannot be processed and bilirubin may be deposited in the nuclei of the brain and degenerative nerve cells producing kernicterus.
UDPGT
A fetus with hemolytic disease does not develop ___________ because the placenta normally removes the bilirubin.
hyperbilirubinema (jaundice)
Some of the bilirubin may appear in the amniotic fluid, and monitoring the concentration by spectrophotometer at _________ provides a means of determining the degree and progression of fetal hemolytic disease.
450 nm wavelength (Liley’s test)
The ____ capacity of albumin for unconjugated bilirubin is the basic defense for prevention of kernicterus in HDN and infantile jaundice.
binding
Kernicterus, as seen in Crigler-Najjarsyndrome, is the deposition of bilirubin in the brain, particularly affecting the ______, mainly the _______, causing severe _______ and _______.
basal ganglia ; lenticular nucleus ; motor dysfunction and retardation
_____________ may cause the blood-brain barrier resulting in kernicterus.
Unbound bilirubin (free bilirubin)
Measurement of ____ is a sensitive and specific marker for hepatic and post-hepatic jaundice because it is not elevated in hemolytic anemia.
B2
In adults, _____________ is the most common cause of hyperbilirubinemia
cholelithiasis (presence of gallstones)
In biliary obstruction, ________ will re-enter the circulation and accumulate and spontaneously form a covalent bond with albumin, thereby prolonging its half-life in the circulation.
conjugated bilirubin
Obstruction of the biliary tract also causes elevated _________ and is associated with the normal excretion of cholesterol in ____.
total cholesterol ; bile
______ injury causes loss of conjugation of transported bilirubin, so that unconjugated bilirubin also rises in plasma.
Hepatocyte
In _________, because insufficient viable liver tissue remains, and because fibrosis destroys the cholangioles, both indirect and direct bilirubin tend to be elevated
panhepatic cirrhosis
_______ is caused by infection with the hepatitis D virus (HDV) and is considered to be the most severe form of viral hepatitis in humans a s it occurs only in individuals positive for the ________
Hepatitis D ; HBV surface antigen(HBsAg).
a defective RNA viroid that requires HBsAg for transmission.
HDV
In Rotor syndrome, caused by a mutation in the SLC01B1 and SLCO1B3 genes, block in the excretion of conjugated bilirubin may occur where both forms of bilirubin is increased in plasma, but the serum level of ___ is higher than ___
B2 ; B1
_______ should be avoided since it may affect the reaction of bilirubin with the diazo reagent, causing: false decrease.
Hemolysis
The sample should be protected from ___________ as it would cause significant reduction in the actual concentration of bilirubin and it should be analyzed within ______
after collection.
light exposure (fluorescent lamp, indirect and direct sunlight) ; 2 to 3 hours
Visible icterisia occurs when bilirubin is ______
25 mg/L.
Principle: Van den Bergh reaction is the diazotization of bilirubin to produce azobilirubin.
Bilirubin Assay
Bilirubin Assays
Evelyn and Malloy Method
Jendrassikand Grof
Coupling Accelerator: Methanol
Main reagent: Diazo reagents
Diazo A 0.1% Sulfanilic Acid + HCI Diazo B = 0.5% Sodium Nitrite
1.5% HCI
Final reaction: Pink to purple azobilirubin at 560nm
Evelyn and Malloy Method
Main reagent in Evelyn and Malloy Method is Diazo reagent what are those?
Diazo A 0.1% Sulfanilic Acid + HCI
Diazo B = 0.5% Sodium Nitrite
Diazo Blank = 1.5% HCI
a bilirubin assay that is most commonly used method and is popular technique for the discreet analyzers.
Jendrassik and Grof
a bilirubin assay that is more sensitive compared to Evelynand Malloy method.
Jendrassik and Grof
Jendrassik and Grof is not affected by ___ changes and the presence of hemoglobin is up to _____
pH ; 750 mg/dL
Jendrassik and Grof main reagent
Diazo reagent
Jendrassik and Grof coupling accelerator
caffeine sodium benzoate
Jendrassik and Grof buffer
sodium acetate
In Jendrassik and Grof, __________ Terminates the initial reaction and destroys the excess diazo reagent
Ascorbic acid:
In Jendrassik and Grof, _______ Provides an alkaline pH
Alkaline tartrate
Final reaction In Jendrassik and Grof:
Blue azbilirubin at 600 nm
The purpose of adding a methanol or caffeine benzoate solution is to allow indirect bilirubin to react (solubilize) with the _______.
color reagent
________ is preferred over _____ because the latter promotes protein precipitation and increases turbidity.
Caffeine-benzoate ; methanol
Conjugated bilirubin produces color in ______ solution.
aqueous
In the measurement of the total bilirubin, the unconjugated fraction produced a color only after the addition of the ______
accelerant
Total bilirubin is measured ______ after adding methanol or caffeine solution.
15 minutes
Bilirubin absorbs light maximally at _____ and imparts a yellow color to ________
450nm ; amniotic fluid.
disease associated with increased B1
- Gilbert’s Syndrome
- Crigler-Najjar Syndrome
- Hemolytic anemia
- Hepatocellular disease
- Lucey Driscoll Syndrome
- G-6-PD deficiency
disease associated with increased B2
1 . Biliary obstruction (gall stones)
2 . Pancreatic (head) cancer
3. Dubin-Johnson Syndrome
4. Alcoholic and viralhepatitis
5. Biliary atresia
6. Hepatocellular disease
7. Septicemia
8. Rotor syndrome
a colorless end product of bilirubin metabolism that is oxidized by intestinal bacteria to the brown pigment stercobilin (urobilin).
Urobilinogen
Urobilinogen is either excreted in ____ and _____ or reabsorbed in to the ______ and returned to the _____.
urine and feces, ; portal blood ; liver
Absence of this substance in urine or stool denotes complete biliary obstruction
Urobilinogen
In Urobilinogen, the collection of the sample, avoid exposure to ______
direct light.
In Urobilinogen, the sample preparation the sample should be collected ______ after a meal (preferably ____ meal)
2 hours ; noon
Presence of drugs in urobilinogen (methyldopa and nitrofurantoin)
False increased
If urobilinogen was exposed to light and air.
False decreased
method in urobilinogen
Ehrlich’s method (p-dimethyl aminobenzaldehyde reagent)
ref range of urobilinogen in urine
Urine = *0.3-1.0Ehrlich units/2hour or 0.5-4 Ehrlichunits/day
ref range of urobilinogen in feces
F e c e s = *80-280 Ehrlich units/24 hours
A test for hepatocellular function and potency of bile duct, however, rarely used
Bromsulphthalein (BSP) Dye Excretion Test
It determines the ability of protein albumin to transport the exogenous dye to the liver where it is excreted in the bile.
Bromsulphthalein (BSP) Dye Excretion Test
Bromsulphthalein (BSP) Dye Excretion Test procedure
BSP dye is administered intravenously.
Dose: 5 mg/kg body weight of the patient
Sample Collection: After 45 minutes of IV dose
Normal/Expected Results: After 45 minutes: +/-5% dye retention
Mac Donald
(Single Collection Method)
Dose: 2 mg/kg body weight of the patient
Sample Collection: After 5 minutes and after 30 minutes of IV dose
Normal/Expected Results:
After 5 minutes: 50% dye retention After 30 minutes: 0% dye retention
Rosenthal W hite (Double Collection Method)
