Labs of GI - Schoenwald Exam 3

Question 1

What are the Vitamin K dependent coagulation factors? Where are they produced?

Answer 1

Factors II, VII, IX, and X. Produced in the liver

Question 2

What is measured on a standard liver function test (LFT)? (3 things produced by the liver)

Answer 2

1. Albumin
2. Prealbumin
3. Prothrombin

Question 3

What is the normal range for albumin?

Answer 3

3.5 - 5 g/dl

Question 4

What is the main function of albumin?

Answer 4

Maintains plasma oncotic pressure. Main carrier of hormones, drugs, anions and fatty acids. “Carrier protein”

Question 5

A patient with severe damage to the liver (such as in cirrhosis) would have an (increased/decreased) albumin level

Answer 5

Decreased albumin

Question 6

What are some non-hepatic causes of hypoalbuminemia?

Answer 6

• malnutrition
• malabsorption
• protein loss from kidney or gut
• increased volume of distribution (ascites or overhydration)
• pregnancy
• burns
• trauma
• alcohol use

Question 7

A patient’s labs come back with mildly decreased albumin levels. Would you expect them to be symptomatic? What kind of symptoms can you expect from hypoalbuminemia?

Answer 7

No symptoms until albumin levels are very low.

Symptoms you may see with significantly low albumin levels: peripheral edema, ascites, pulmonary edema

*remember albumin maintains oncotic pressure. If low, fluid leaks into interstitial spaces

Question 8

What other lab value on a CMP may be affected with low albumin levels?

Answer 8

Calcium levels

*you need to correct for low albumin to get an accurate calcium level (unless it is an ionized calcium lab)

Question 9

What is the normal range for prealbumin?

Answer 9

Prealbumin: 16-40 mg/dl

(really hoping we don’t actually have to memorize these, but just in case!)

Question 10

Which hepatic protein is more sensitive to dietary protein intake, albumin or prealbumin? Is it affected by hydration state, too?

Answer 10

Prealbumin is more sensitive to dietary protein intake. It is not affected by hydration status.

*not used by nutritionists much anymore, but can be useful in a patient who was found down and unable to give a good history. (low prealbumin = they haven’t eaten in a while)

Question 11

Which of these is not synthesized by the liver?

A) prealbumin

B) prothrombin

C) globulin

D) albumin

Answer 11

C) globulin

Question 12

How do you calculate globulin levels?

Answer 12

Total protein - albumin = globulin

(Globulin levels are not given on a CMP. TP and albumin are)

Question 13

What is globulin a measure of?

Answer 13

Total immunoglobulins in serum (antibodies)

Question 14

What is the total protein level useful in assessing for? What is a normal range for TP?

Answer 14

Immune or hematological dysfunction. TP is of little value in assessing liver disease (if the albumin is known)

nl range: 5.5-8.3 g/dl (again hopefully we don’t need to memorize these, but just in case)

Question 15

What are the normal ranges for prothrombin time and INR?

Answer 15

Prothrombin time: 10-13 seconds

INR 1-2

Question 16

Prothrombin time measures the (extrinsic/intrinsic) coagulation pathway. Which clotting factors?

Answer 16

Extrinsic

Factors II, V, VII, and X

Question 17

Would you expect to see a prolonged or shortened prothrombin time in a patient with liver disease?

Answer 17

Prolonged

-other causes of prolonged PT: Coumadin therapy, Vit K deficiency, clotting factor deficiency, and autoimmine diseases (lupus)

Question 18

Activated partial thromboplastin time (aPTT) is (longer/shorter) than PTT and measures the (extrinsic/intrinsic) clotting pathway. What clotting factors are measured?

Answer 18

Activated partial thromboplastin time (aPTT) is longer (30-40sec) than PTT and measures the intrinsic ​clotting pathway.

Factors II, V, VII, IX, X, and XI

Question 19

True or False:

aPTT is not dependent on liver function

Answer 19

True

Question 20

_______ is useful in monitoring heparin therapy, while ______ is used to monitor coumadin therapy.

Answer 20

aPTT is useful in monitoring heparin therapy, while PT is used to monitor coumadin therapy.

Question 21

Which liver enzyme when elevated over 4x its normal range is suggestive of cholestasis?

Answer 21

Alkaline phosphatase (ALP)

Question 22

From what two organs does most alkaline phosphatase come from? Where else can ALP come from?

Answer 22

Liver and bone (elevated in Paget’s disease, ‘member?)

Can also come from placenta, small intestine, kidneys, and leukocytes

Question 23

When would you order a GGT lab?

Answer 23

To monitor for alcohol abuse (used with an alcohol abstinence plan to monitor for adherence) GGT decreases by ~50% in 2 weeks with abstinence

Question 24

A patient’s labs come back with elevated ALP and elevated GGT. Is this likely a hepatic or nonhepatic issue?

Answer 24

Hepatic

An elevated ALP with normal GGT would likely indicate nonhepatic issue

Question 25

What are AST and ALT used to assess?

Answer 25

Assess for cellular damage. AST/ALT released into serum due to leaky or necrotic hepatocytes

Question 26

An elevated AST **without** ALT elevation suggests a _____ source.

Answer 26

An elevated AST **without** ALT elevation suggests a **cardiac** source.

Question 27

A patient's AST/ALT labs are as follows. Is this more likely an alcoholic liver disease or viral hepatitis? **AST:** 700 **ALT:** 720

Answer 27

**Viral Hepatitis** AST/ALT ratio \<1

Question 28

A patient's AST/ALT labs are as follows. Is this more likely an alcoholic liver disease or viral hepatitis? AST: 300 ALT: 100

Answer 28

**Alcoholic liver disease** AST/ALT ratio \>1

Question 29

LDH is typically elevated in liver disease. Is LDH specific for liver disease or is it found in other organs?

Answer 29

**LDH: nonspecific.** Also found in heart, liver, blood, brain, skeletal mm, and lungs

Question 30

What is the normal total bilirubin range?

Answer 30

Total bili: 0.3-1 mg/dl

Question 31

What is the hallmark sign of elevated bilirubin?

Answer 31

Jaundice

Question 32

Gilbert's syndrome is a benign trait that shows intermittent elevations of what lab value that's typically relevant to liver function?

Answer 32

unconjugated bilirubin (**non**hepatic source) \*don't forget to pronounce Gilbert like the name of a fancy French restaurant and not like your uncle from Texas

Question 33

Hepatic encephalopathy is caused by elevated ______ levels.

Answer 33

Hepatic encephalopathy is caused by elevated **ammonia** levels.

Question 34

Where does the majority of ammonia originate from?

Answer 34

Intestinal bacteria catabolism

Question 35

Normal ammonia range:

Answer 35

Ammonia: 30-70 ug/dl

Question 36

What tumor marker is elevated in 70-80% of hepatocellular carcinoma patients?

Answer 36

alpha fetoprotein (normal 10-20 ng/ml)

Question 37

What are the exocrine and endocrine enzymes of the pancreas?

Answer 37

Exocrine: Trypsin, chymotrypsin, amylase, and lipase Endocrine: insulin and glucagon

Question 38

Which enzymes are most useful in assessing for pancreatitis?

Answer 38

Amylase and lipase

Question 39

Pancreatic enzymes: _______ breaks down starch and _____ aids in fat digestion

Answer 39

Pancreatic enzymes: **amylase** breaks down starch and **lipase** aids in fat digestion

Question 40

Which pancreatic enzyme rises faster upon onset of acute pacreatitis: Lipase or Amylase? When does it peak?

Answer 40

**Amylase:** rises within 2-6 hrs of onset, peaks at 20-30 hrs Lipase rises and declines slower

Question 41

What is the tumor marker measured to monitor treatment of colorectal carcinoma and pacreatic cancer?

Answer 41

**Carcinoembryonic antigen (CEA)** used to monitor progress of treatment, *not diagnosis*