Exam 3 Clinical Chemistry Study Guide | Dr. Rodarte

b

Gilbert's disease is characterized by which pattern of bilirubin elevation?

A. Persistent direct (conjugated) hyperbilirubinemia

B. Intermittent indirect (unconjugated) hyperbilirubinemia

C. Mixed direct and indirect hyperbilirubinemia

D. Decreased total bilirubin levels

E. Elevated direct bilirubin only

d

patient with Gilbert's disease most commonly has a total bilirubin level in which range?

A. 0.2-0.8 mg/dL

B. 4.5-6.0 mg/dL

C. 6.0-10.0 mg/dL

D. 1.5-3.0 mg/dL

E. >10 mg/dL

c

In Gilbert's disease, which bilirubin fraction is elevated?

A. Direct bilirubin

B. Delta bilirubin

C. Indirect bilirubin

D. Both direct and indirect bilirubin equally

E. Neither fraction is elevated

b

Which of the following laboratory findings is expected in Gilbert's disease?

A. Elevated direct bilirubin with normal indirect bilirubin

B. Elevated indirect bilirubin with normal direct bilirubin

C. Both direct and indirect bilirubin decreased

D. Elevated alkaline phosphatase only

E. Elevated AST and ALT only

d

Which statement about bilirubin levels in Gilbert's disease is correct?

A. Total bilirubin is usually greater than 10 mg/dL

B. Total bilirubin is always above 4.5 mg/dL

C. Total bilirubin is consistently normal

D. Total bilirubin fluctuates between 1.5-3.0 mg/dL

E. Total bilirubin is below 1.0 mg/dL

c

Which condition is notably absent in Gilbert's disease?

A. Increased indirect bilirubin

B. Normal direct bilirubin

C. Hemolysis

D. Mild hyperbilirubinemia

E. Fluctuating bilirubin levels

e

Which of the following best describes direct bilirubin levels in Gilbert's disease?

A. Markedly elevated

B. Slightly elevated

C. Severely decreased

D. Fluctuating widely

E. Within normal limits

d

A patient presents with mild jaundice and labs showing elevated indirect bilirubin, normal direct bilirubin, and no evidence of hemolysis. What is the most likely diagnosis?

A. Hemolytic anemia

B. Obstructive jaundice

C. Acute hepatitis

D. Gilbert's disease

E. Cholestasis

Answer: A, B, D, F, G

Which of the following are characteristic findings of Gilbert's disease? (Select all that apply)

A. Intermittent indirect (unconjugated) hyperbilirubinemia

B. Total bilirubin typically between 1.5-3.0 mg/dL

C. Elevated direct (conjugated) bilirubin

D. Normal direct bilirubin

E. Presence of hemolysis

F. Elevated indirect bilirubin

G. Total bilirubin exceeding 4.5 mg/dL

H. Persistent severe hyperbilirubinemia (>10 mg/dL)

d

What is the function of ligandin in bilirubin metabolism?

A. Conjugates bilirubin in the endoplasmic reticulum

B. Transports conjugated bilirubin into bile canaliculi

C. Breaks down heme into bilirubin

D. Transports unconjugated bilirubin within hepatocytes to the ER for conjugation

E. Converts indirect bilirubin into direct bilirubin in plasma

b

Ligandin primarily facilitates which of the following processes?

A. Movement of conjugated bilirubin into bile

B. Transport of unconjugated bilirubin inside hepatocytes

C. Conversion of bilirubin to urobilinogen

D. Excretion of bilirubin in urine

E. Oxidation of bilirubin in the bloodstream

e

Which type of bilirubin is transported by ligandin?

A. Direct (conjugated) bilirubin

B. Delta bilirubin

C. Urobilinogen

D. Biliverdin

E. Indirect (unconjugated) bilirubin

c

What is the primary role of the proximal convoluted tubule (PCT)?

A. Secretion of potassium only

B. Filtration of blood plasma

C. Reabsorption of water, glucose, amino acids

D. Storage of urine

E. Concentration of urine via ADH

c

Approximately what percentage of water, sodium, and chloride is reabsorbed in the PCT?

A. 25%

B. 50%

C. 75%

D. 90%

E. 100%

d

Which substance is completely reabsorbed in the PCT under normal conditions?

A. Urea

B. Sodium

C. Chloride

D. Glucose

E. Creatinine

e

Which of the following is TRUE regarding amino acids in the PCT?

A. They are not reabsorbed

B. Only 50% are reabsorbed

C. They are secreted into urine

D. They are partially filtered but not reabsorbed

E. Almost all are reabsorbed

a

Which combination of substances is primarily reabsorbed in the PCT?

A. Water, glucose, amino acids, electrolytes

B. Urea, creatinine, uric acid

C. Hydrogen ions, potassium only

D. Bicarbonate only

E. Proteins and lipids only

d

Which of the following substances is NOT almost completely reabsorbed in the PCT?

A. Amino acids

B. Glucose

C. Electrolytes

D. Water

E. All are almost completely reabsorbed

d

An LD1 level greater than LD2 (LD1 > LD2) is most indicative of which condition?

A. Liver failure

B. Skeletal muscle injury

C. Pulmonary embolism

D. Myocardial infarction

E. Kidney disease

c

Which LDH isoenzyme pattern is associated with myocardial infarction?

A. LD2 > LD1

B. LD3 > LD2

C. LD1 > LD2

D. LD5 > LD4

E. LD4 > LD3

c

Physiologic jaundice of the newborn is characterized by which type of bilirubin elevation?

A. Direct (conjugated) bilirubin only

B. Mixed direct and indirect bilirubin

C. Indirect (unconjugated) bilirubin

D. Delta bilirubin

E. No change in bilirubin

e

Which of the following best describes total bilirubin levels in physiologic jaundice of the newborn?

A. Decreased total bilirubin

B. Normal total bilirubin

C. Markedly decreased total bilirubin

D. Slightly decreased total bilirubin

E. Increased total bilirubin

b

Which bilirubin fraction remains normal in physiologic jaundice of the newborn?

A. Indirect bilirubin

B. Direct bilirubin

C. Delta bilirubin

D. Urobilinogen

E. Biliverdin

c

What is the underlying enzymatic cause of physiologic jaundice of the newborn?

A. Increased glucuronyl transferase activity

B. Absence of ligandin

C. Decreased glucuronyl transferase (UDPGT) activity

D. Increased hemolysis only

E. Increased bile secretion

c

Which of the following best summarizes the lab findings in physiologic jaundice of the newborn?

A. ↑ direct bilirubin, normal indirect bilirubin

B. ↓ total bilirubin, ↑ direct bilirubin

C. ↑ total bilirubin, ↑ indirect bilirubin, normal direct bilirubin

D. Normal total bilirubin, ↑ direct bilirubin

E. ↑ direct bilirubin only

d

A newborn presents with jaundice. Labs show elevated total bilirubin, elevated indirect bilirubin, normal direct bilirubin, and decreased UDPGT activity. What is the most likely diagnosis?

A. Hemolytic disease of the newborn

B. Biliary atresia

C. Neonatal hepatitis

D. Physiologic jaundice of the newborn

E. Obstructive jaundice

d

Dubin-Johnson syndrome is characterized by which type of hyperbilirubinemia?

A. Indirect (unconjugated) hyperbilirubinemia

B. Mixed hyperbilirubinemia

C. No change in bilirubin

D. Direct (conjugated) hyperbilirubinemia

E. Decreased bilirubin levels

c

What is the typical total bilirubin range in Dubin-Johnson syndrome?

A. 0.5-1.0 mg/dL

B. 1.0-1.5 mg/dL

C. 2-6 mg/dL

D. 6-10 mg/dL

E. >10 mg/dL

e

In Dubin-Johnson syndrome, what proportion of total bilirubin is direct bilirubin?

A. <10%

B. 10-25%

C. 25-40%

D. Exactly 50%

E. >50%

c

What is the underlying defect in Dubin-Johnson syndrome?

A. Increased bilirubin production

B. Defective bilirubin conjugation

C. Defective bilirubin excretion

D. Increased hemolysis

E. Impaired bilirubin uptake into hepatocytes

d

Which of the following best explains the presence of delta bilirubin in Dubin-Johnson syndrome?

A. Increased breakdown of hemoglobin

B. Binding of unconjugated bilirubin to albumin

C. Conversion of bilirubin to biliverdin

D. Binding of conjugated bilirubin to albumin

E. Increased renal excretion of bilirubin

Answer: B, D, F, H, J, K

Which of the following are features of Dubin-Johnson syndrome? (Select all that apply)

A. Indirect (unconjugated) hyperbilirubinemia

B. Direct hyperbilirubinemia

C. Total bilirubin <1.0 mg/dL

D. Total bilirubin 2-6 mg/dL

E. <50% of bilirubin is direct

F. >50% of bilirubin is direct

G. No delta bilirubin formation

H. Formation of delta bilirubin

I. Normal bilirubin excretion

J. Defective bilirubin excretion

K. Impaired bile excretion of conjugated bilirubin

L. Normal excretion of conjugated bilirubin

b

In heart failure with low blood volume and decreased sodium, which system is primarily activated?

A. Parasympathetic nervous system

B. Renin-angiotensin-aldosterone system

C. Complement system

D. Coagulation cascade

E. Glycolytic pathway

d

What is the effect of angiotensin on aldosterone?

A. Decreases aldosterone secretion

B. Has no effect on aldosterone

C. Directly inhibits aldosterone

D. Stimulates aldosterone release

E. Destroys aldosterone

c

Aldosterone primarily increases reabsorption of which substance?

A. Potassium

B. Calcium

C. Sodium

D. Glucose

E. Bicarbonate

b

Increased sodium reabsorption leads to which of the following?

A. Decreased blood volume

B. Increased water retention

C. Increased potassium excretion only

D. Decreased urine concentration

E. Loss of fluid from the body

c

Which sequence correctly describes the physiologic response in heart failure?

A. ↑ blood volume → ↓ angiotensin → ↓ aldosterone

B. ↓ Na → ↓ angiotensin → ↑ aldosterone

C. ↓ blood volume → ↑ angiotensin → ↑ aldosterone

D. ↑ Na → ↑ aldosterone → ↓ water retention

E. ↓ aldosterone → ↑ sodium excretion

Answer: A, B, D, E, H

Which of the following are consequences of RAAS activation in heart failure? (Select all that apply)

A. Increased sodium reabsorption

B. Increased water retention

C. Decreased aldosterone levels

D. Increased angiotensin levels

E. Increased blood volume

F. Decreased sodium reabsorption

G. Decreased water retention

H. Increased aldosterone secretion

b

Which of the following is a hallmark laboratory finding in nephrotic syndrome?

A. Low urine protein

B. Proteinuria

C. Decreased lipid levels

D. Elevated hemoglobin

E. Increased serum albumin

d

What happens to serum protein levels in nephrotic syndrome?

A. Increased serum protein

B. Normal serum protein

C. Slightly increased albumin

D. Hypoalbuminemia

E. No change in protein levels

c

Which lipid abnormality is associated with nephrotic syndrome?

A. Hypolipidemia

B. Normal lipid levels

C. Hyperlipidemia

D. Decreased cholesterol only

E. Decreased triglycerides only

c

Which of the following urinary findings is seen in nephrotic syndrome?

A. Glycosuria only

B. Hematuria without casts

C. Lipiduria

D. No abnormal findings

E. Ketonuria only

d

Which type of casts may be present in nephrotic syndrome?

A. WBC casts

B. Granular casts

C. Fatty casts only

D. RBC casts

E. Hyaline casts only

b

Which combination best describes nephrotic syndrome labs?

A. Low urine protein, high serum protein, hypolipidemia

B. High urine protein, low serum protein, hyperlipidemia

C. Normal urine protein, normal serum protein, normal lipids

D. Low urine protein, low serum protein, hyperlipidemia

E. High urine protein, high serum protein, low lipids

Answer: A, C, E, G, I

Which of the following are laboratory findings in nephrotic syndrome? (Select all that apply)

A. Proteinuria

B. Low urine protein

C. Hypoalbuminemia

D. High serum albumin

E. Hyperlipidemia

F. Hypolipidemia

G. Lipiduria

H. Absence of urinary lipids

I. RBC casts

J. No casts present

K. Increased blood protein levels

L. Normal lipid levels

b

Which type of bilirubin is elevated in biliary obstruction?

A. Indirect (unconjugated) bilirubin

B. Direct (conjugated) bilirubin

C. Delta bilirubin only

D. No change in bilirubin

E. Decreased bilirubin

d

Which enzyme levels are typically elevated in biliary obstruction?

A. AST and ALT

B. CK and LDH

C. Amylase and lipase

D. ALP and GGT

E. Troponin and CK-MB

e

What happens to urobilinogen levels in biliary obstruction?

A. Increased urobilinogen

B. Normal urobilinogen

C. Decreased but present

D. Fluctuating levels

E. Absent urobilinogen

c

Which combination best describes biliary obstruction?

A. ↑ indirect bilirubin, ↑ AST/ALT, ↑ urobilinogen

B. ↓ bilirubin, normal enzymes, ↑ urobilinogen

C. ↑ direct bilirubin, ↑ ALP/GGT, no urobilinogen

D. Normal bilirubin, ↓ ALP, ↑ urobilinogen

E. ↑ indirect bilirubin only

e

A patient has elevated ALP, elevated GGT, increased direct bilirubin, and no urobilinogen. What is the most likely diagnosis?

A. Hemolytic anemia

B. Gilbert's disease

C. Acute hepatitis

D. Nephrotic syndrome

E. Biliary obstruction

b

What is the primary clinical use of cystatin C?

A. Detect liver dysfunction

B. Detect early kidney dysfunction

C. Measure cardiac enzymes

D. Assess lung function

E. Diagnose anemia

c

Compared to creatinine, cystatin C is:

A. Less sensitive for kidney dysfunction

B. Equal in sensitivity at all stages

C. More sensitive for early kidney dysfunction

D. Only useful in late-stage disease

E. Not related to kidney function

c

What reaction occurs when bilirubin reacts with diazo reagent?

A. Formation of biliverdin

B. Formation of urobilinogen

C. Formation of azobilirubin

D. Breakdown into heme

E. Conversion to delta bilirubin

d

The product formed when bilirubin reacts with diazo is:

A. Yellow complex

B. Blue complex

C. Green pigment

D. Purple complex

E. Red precipitate

c

The diazo reaction is primarily used to measure:

A. Glucose

B. Lipids

C. Bilirubin

D. Proteins

E. Electrolytes

c

What is the primary defect in renal tubular acidosis (RTA)?

A. Inability to filter blood

B. Inability to produce alkaline urine

C. Inability to produce acid urine

D. Excess glucose reabsorption

E. Increased protein filtration

false

T/F: renal tubular acidosis produces acid urine

Troponins → CK-MB → Myoglobin → CK → LDH

What enzymes increases first to last in a patient with an AMI?

d

When elevated amounts of bilirubin are presented to the liver with increased unconjugated bilirubin, what type of jaundice occurs?

A. Hepatic jaundice

B. Obstructive jaundice

C. Post-hepatic jaundice

D. Pre-hepatic (hemolytic) jaundice

E. Neonatal jaundice

b

Which test is used to provide information about coronary heart disease?

A. ALT

B. CRP

C. Creatinine

D. Bilirubin

E. Hemoglobin

d

A patient with an acute bleed is most likely to develop which type of kidney injury?

A. Intrinsic AKI

B. Post-renal AKI

C. Chronic kidney disease

D. Pre-renal AKI

E. Glomerulonephritis

c

Which of the following helps assess the metabolic component of acid-base balance?

A. Sodium

B. Potassium

C. Bicarbonate

D. Chloride

E. Albumin

c

Absence of urobilinogen in urine is most indicative of which condition?

A. Hemolytic anemia

B. Liver failure

C. Biliary obstruction

D. Nephrotic syndrome

E. Acute hepatitis

c

Where is urobilinogen formed?

A. Liver

B. Kidneys

C. Intestine

D. Gallbladder

E. Pancreas

c

Urobilinogen is produced by which of the following?

A. Liver enzymes

B. Kidney filtration

C. Colon bacteria

D. Pancreatic enzymes

E. Blood plasma proteins

MI, stroke, exercise, muscle disease

CK can increase in what conditions?

c

Creatinine clearance is corrected using body surface area to account for differences in:

A. Liver function

B. Blood pressure

C. Muscle mass

D. Lung capacity

E. Electrolyte levels

b

Bilirubin becomes unstable under which condition?

A. Exposure to heat

B. Exposure to light

C. Exposure to cold

D. Exposure to oxygen

E. Exposure to water

d

Which enzyme is responsible for conjugating bilirubin in hepatocytes?

A. Heme oxygenase

B. Biliverdin reductase

C. Lactate dehydrogenase

D. UDP-glucuronyl transferase

E. Alanine aminotransferase

b

What is the primary clinical use of 5′-nucleotidase?

A. Assess kidney function

B. Confirm hepatobiliary disease

C. Measure cardiac enzymes

D. Evaluate glucose metabolism

E. Diagnose anemia

b

5′-nucleotidase is most useful for differentiating between which two sources of elevated ALP?

A. Kidney vs liver

B. Liver vs bone

C. Heart vs lung

D. Pancreas vs intestine

E. Muscle vs brain

c

What is the primary function of ADH in the kidney?

A. Decreases sodium reabsorption

B. Increases glucose excretion

C. Increases water reabsorption

D. Decreases potassium secretion

E. Increases protein filtration

d

What is the most sensitive marker for alcoholic liver disease?

A. AST

B. ALT

C. ALP

D. GGT

E. Bilirubin

a

Myoglobin levels increase in which condition?

A. Rhabdomyolysis

B. Biliary obstruction

C. Diabetes mellitus

D. Hypothyroidism

E. Asthma

d

Sodium levels in the body are primarily regulated by which system?

A. Respiratory system

B. Digestive system

C. Nervous system

D. Renin-angiotensin-aldosterone system

E. Immune system

c

How is bilirubin transported in the bloodstream?

A. Free in plasma

B. Bound to hemoglobin

C. Bound to albumin

D. Bound to glucose

E. Bound to lipids

c

What is β2-microglobulin primarily used to evaluate?

A. Liver function

B. Cardiac function

C. Renal tubular function

D. Lung capacity

E. Blood glucose levels

b

What breakdown product of bilirubin metabolism is formed in the colon from oxidation of urobilinogen?

A. Biliverdin

B. Urobilin

C. Hemoglobin

D. Delta bilirubin

E. Porphyrin

c

Urobilinogen is converted into which compound in the colon?

A. Bilirubin

B. Biliverdin

C. Stercobilin

D. Albumin

E. Heme

b

Which bilirubin fraction is elevated in obstructive jaundice?

A. Indirect (unconjugated) bilirubin

B. Direct (conjugated) bilirubin

C. Delta bilirubin only

D. No bilirubin change

E. Decreased bilirubin

d

What happens to urobilinogen levels in obstructive jaundice?

A. Increased

B. Normal

C. Decreased but present

D. Absent

E. Fluctuating

c

Which combination best describes obstructive jaundice?

A. ↑ indirect bilirubin, ↑ urobilinogen

B. Normal bilirubin, ↓ urobilinogen

C. ↑ direct bilirubin, no urobilinogen

D. ↓ bilirubin, ↑ urobilinogen

E. Mixed bilirubin, normal urobilinogen

c

Why is urobilinogen absent in obstructive jaundice?

A. Increased hemolysis

B. Increased conjugation

C. Bile cannot reach the intestine

D. Increased renal filtration

E. Decreased albumin

b

What does an increase in enzyme levels typically indicate?

A. Normal cell function

B. Cell injury or necrosis

C. Decreased metabolism

D. Increased protein synthesis

E. Improved organ function

c

What is kernicterus?

A. Bilirubin deposition in kidneys

B. Bilirubin deposition in liver

C. Bilirubin deposition in brain

D. Decreased bilirubin levels

E. Increased hemoglobin production

b

What is the main consequence of bilirubin deposition in kernicterus?

A. Increased RBC production

B. Cell death

C. Increased liver enzymes

D. Enhanced metabolism

E. Decreased oxygen levels

c

What is jaundice?

A. Blue discoloration of the skin

B. Yellow discoloration from urobilinogen accumulation

C. Yellow discoloration from bilirubin accumulation

D. Green discoloration from bile

E. Pale discoloration from anemia

b

Jaundice results from accumulation of which substance?

A. Urobilinogen

B. Bilirubin

C. Glucose

D. Lipids

E. Calcium

c

What is the cause of neonatal physiologic jaundice of hepatic type?

A. Increased hemolysis

B. Biliary obstruction

C. UDP-glucuronyl transferase deficiency

D. Increased albumin levels

E. Increased bile flow

d

Neonatal physiologic jaundice of hepatic type is due to deficiency of which enzyme?

A. Heme oxygenase

B. Biliverdin reductase

C. Lactate dehydrogenase

D. UDP-glucuronyl transferase

E. Alkaline phosphatase

c

What is the most specific marker for myocardial infarction (MI)?

A. CK

B. LDH

C. Troponin

D. Myoglobin

E. AST

b

Troponin used in MI diagnosis includes which subtypes?

A. cTnA and cTnB

B. cTnI and cTnT

C. cTnM and cTnN

D. cTnX and cTnY

E. cTnL and cTnP

c

Which cardiac marker remains elevated for the longest period after myocardial infarction?

A. Myoglobin

B. CK-MB

C. Troponin

D. LDH

E. AST

c

CK-MM is primarily elevated in which type of tissue injury?

A. Cardiac muscle

B. Brain tissue

C. Skeletal muscle

D. Liver

E. Kidney

d

CK-MB is most associated with injury to which organ?

A. Brain

B. Liver

C. Skeletal muscle

D. Heart

E. Kidney

c

CK-BB is elevated in injury to which tissue?

A. Heart

B. Skeletal muscle

C. Brain

D. Liver

E. Lung

b

Which lab tests are used to assess liver synthetic ability?

A. ALT and AST

B. Albumin and prothrombin time

C. Bilirubin and ALP

D. GGT and LDH

E. Creatinine and urea

c

Which of the following best reflects liver synthetic capacity?

A. AST

B. ALT

C. Albumin

D. Bilirubin

E. GGT

c, f

Which biomarker is most commonly used to assess heart failure? (select all that apply.)

A. AST

B. ALT

C. BNP

D. Creatinine

E. Bilirubin

F. NT-proBNP

Conjugated (direct) bilirubin

Which form of bilirubin is water-soluble?