Clin chem exam review

List the 2 types of disorders of the liver

• excretory 

• synthetic

list 5 things the liver synthesizes

1. Bile 

2. Proteins 

3. Carbohydrates

4. Lipids 

5. clotting factors  

explain the secretory function of the liver

define cholestasis

• stoppage of bile (obstruction)

• within hepatocytes (intra-hepatic) or bile duct (extra-hepatic)

what are 3 categories of testing for the liver

• functional capacity 

• serum activity of liver enzyme tests 

• supplemental diagnostic (liver biopsy etc)

list 4 of the more common functional capacity tests for the liver

1. BSP or ICG 

• clearance or retention  

2. BUN & ammonia (NH3)

• tests livers ability to convert ammonia to urea 

3. Albumin 

• exclusively produced by hepatocytes 

• hypoproteinemia almost always do to albumin loss 

4. Coagulation 

• many clotting factors synthesized by the liver 

how is the liver related to ammonia

• liver convert ammonia to urea 

why are ammonia levels important

with liver dysfunction , what would ammonia and urea levels be in the serum

when would ammonia tolerance test NOT be a good option 

with relation to the liver , why might albumin levels decrease

• renal or intestinal disease

• nutritional problems

what are three globulin groups

• Alpha 

• Beta

• Gamma ( not produced in the liver, produced by immune system)

why is fibrinogen important 

• needed for clotting 

two tests 

• refractometer 

• heat precipitation test 

why should you not use the jugular for venipuncture on a suspected liver dysfunction

• severe bleeding disorders are common with hepatic injury

• so taking blood from the major blood vessel is not smart

why should serum and urine samples be protected from light if doing a liver profile

• light exposure falsely lowers bilirubin levels, b/c bilirubin breaks down when light exposed 

• misleading liver profile 

why is bilirubin a test for liver function ? how is it related to the liver?

explain start to finish normal bilirubin circuit

RBC breakdown

Hemoglobin breakdown (iron, globin, bilirubin) –in spleen

Bilirubin (unconjugated) binds to albumin to travel to liver*

Liver turns unconjugated into conjugated (“conjugates it”)

Most conjugated travels via bile ducts to duodenum for excretion
and small amount reabsorbed back into circulation (which can be
filtered by normal kidney)

In intestine: bacterial fermentation to urobilinogen/stercobilinogen

Oxidized to stercobilin and excreted in feces. Some urobilinogen
reabsorbed into circulation, or oxidized to urobilin and excreted in
urine

The oxidation creates urochrome that gives colour to urine and feces

what is jaundice

• discolouration of body tissues

• due to  Increased amount of circulating bilirubin in plasma 

• conjugated or unconjugated 

• Symptom not disease 

typically where can you find unconjugated vs conjugated bilirubin 

Unconjugated:

• in circulation (blood) bounce to albumin 

Conjugated

• in circulation (blood) from reabsorption from the intestines

• in urine , after reabsorption ( can pass through glomerulus and be filtered out by kidney) 

what is the cause for pre-hepatic jaundice, what is the result for bilirubin

• due to increased RBC destruction 

• increase in both unconjugated and conjugated bilirubin

what is the cause for hepatic jaundice, what is the bilirubin result

• directly related to liver function

• Usually from hepato-cellular damage

• Primary defect

• Secondary to virus, toxins, hepatic lipidosis

Depending on CAUSE, 2 different results:
1. low conjugating ability = high unconjugated bilirubin
2. high conjugated bilirubin due to leakage from cell damage

what is the cause for post-hepatic jaundice

• in ability to excrete bilirubin into the duodenum 

• often due to biliary obstruction 

• Conjugated bilirubin is reabsorbed, therefore no reduction in intestines:

•  o ↓ urobilin in urine

• o ↓ stercobilin in feces
   Chalky coloured stool*

  
  

how are bile acids related to liver function

what serum enzymes indicate liver cell damage , what does it mean if they are elevated

What serum enzymes indicate impaired bile flow? Why would they NOT elevate if there is only primary cell damage

what is phenobarbital 

Why is it important to monitor liver function and enzymes while a patient is on phenobarbital

What specifically should you monitor at least every 6-12 months while on the drug

Why are older patients more at risk during anesthesia?

List 3 specific organ related changes with geriatrics

What are some signs of cardiovascular disease?

Which enzyme can be evaluated to determine if there is cardiovascular damage? Why can it be used?

What are some reasons for this enzyme to be falsely elevated?

How is the anion gap calculated

Why is a normal anion gap higher than zero?

What happens to serum bicarbonate levels during metabolic acidosis

. What are the reasons bicarbonate levels may decrease during metabolic acidosis

What are clinical signs of metabolic acidosis?

What happens to serum bicarbonate levels during metabolic alkalosis?

How are albumin and a decreased anion gap related?

What are clinical signs of metabolic alkalosis?

What are signs of hypothyroidism

What serum value would be evaluated to help make this diagnosis

What other tests can be done

In what species is hyperthyroidism more prevalent? What are the signs

What is the parathyroid gland, what does it do, what condition primarily affects it, and what bone result can this cause in the patient

What is Cushing’s?

How do pituitary and primary adrenal Cushing’s disease differ

What are some clinical signs of Cushing’s

What is Addison’s disease

How does the pituitary/adrenal gland/ACTH/cortisol negative feedback loop work? (understand all parts of the loop and the diagrams from the PowerPoint presentation

Which test confirms Addison’s? What would the results be?

Which test differentiates between pituitary and adrenal Cushing’s (not just a screen)? What would the results be?