LFTs Flashcards
Functions of the Liver
- Involved in amino acid, albumin, angiotensinogen, and cholesterol biosynthesis as well as carbohydrate metabolism (Gluconeogenesis; Glycogenolysis; Glycogenesis)
- Produces thrombopoeitin, coag factors (I, II, V, VII, IX, X, and XI) as well as protein C and S and antithrombin
- Main site of RBC production during the first 32 weeks of fetal development (then bone marrow takes over)
- Converts ammonia to urea.
- Stores glycogen, vitamin A (1-2 years supply), vitamin D (1-4 months supply), vitamin B12, iron, and copper
- Contains many immunologically active cells, acting as a “sieve” for antigens carried to it via the portal system.
- Facilitates the catabolism of hemoglobin and excretes bile.
This is the term for the breakdown of glycogen into glucose.
Glycogenolysis
This is the term for the formation of glycogen from glucose.
Glycogenesis
This is the term for the synthesis of glucose from certain amino acids, lactate or glycerol.
Gluconeogenesis
T/F: The pancreas has exocrine and endocrine functions.
True;
Proteases, Amylases, and Lipases allow for exocrine function.
Insulin and Glucagon allow for endocrine function.
What tests check for Synthetic Function of the Liver?
Total Protein
Albumin
Prealbumin
PT-INR
What tests check for Excretory Function of the Liver?
ALP
GGT
Total and Direct Bilirubin
5’-Nucleotidase
What tests check for Hepatocellular Injury of the Liver?
ALT and AST
What tests check for Detoxification of the Liver?
Ammonia
The Comprehensive Metabolic Panel (CMP) is a combination of ______ and ______. What individual tests does this include?
BMP and HFP (LFTs)
- Na
- K
- Cl
- CO2
- BUN
- Cr
- Glucose
- Ca
- Total Protein
- Albumin
- AST
- ALT
- ALP
- Total Bilirubin
**Direct BR and Globulins not typically included in the CMP.
This synthetic product of the liver is a protein that binds free HgB released from RBCs and inhibits its oxidative activity. The complex with HgB is then removed by the spleen.
Haptoglobin
This synthetic product of the liver is used to screen for hemolytic anemia along with LDH.
Haptoglobin
This synthetic product of the liver is a glycoprotein that transports ferric ions (Fe3+). It CAN measure synthetic function BUT is rarely used.
Transferrin
What is the normal range of Albumin?
4.0-5.0 g/dL
_____ grams of albumin are synthesized and excreted daily by the normal liver.
10
As liver damage progresses, albumin synthesis ___________.
Progressively declines
Half life of Albumin is?
18-20 days (with 4% degraded daily)
Albumin levels may be normal in cases of ____________ and ______________.
- Acute Viral Hepatitis
- Drug-Related Hepatotoxicity Jaundice
A patient with chronic liver disease (cirrhosis) will have albumin levels that are _____.
Low (< 4.0) called Hypoalbuminemia
An albumin levels less than 2.5 g/dL gives a ______ prognosis.
Poor
Someone with Hypoalbuminemia could present with…?
- Peripheral Edema
- Ascites
- Pulmonary Edema
Non-hepatic Causes of Hypoalbuminemia
- Protein Malnutrition/Malabsorption
- Loss from the Kidneys or Gut
- Burns
- Trauma
- EtOH Abuse
A patient with dehydration (as noted with BUN and HCt), would have ____ albumin levels.
High (>5.0) called Hyperalbuminemia
Causes of Hyperalbuminemia
- Anabolic Steroids
- False Elevation if pt on Heparin or Ampicillin
Patients with hyperlabuminemia commonly present with what symptom(s)?
None, often asymptomatic.
Normal Range of Prealbumin (Transthyretin)
17.0-34.0 mg/dL
Half life of Prealbumin
~2 days
Prealbumin binds to _________ and _______.
Thryoxine; Retinol
Prealbumin levels respond to nutritional changes ____more/less____ frequently than albumin.
More
Normal Range of Total Protein
6.0 - 8.3 g/dL
Total Protein reflects the sum of ______ and ____.
Albumin and Globulins
How do you find Globulin levels on LFTs?
Total Protein - Albumin = Globulin
What would elevated Globulin Levels cause you to screen for?
Multiple Myeloma (serum urine protein electrophoresis, BM biopsy, etc.)
Normal Range of Serum Globulins
2-3 g/dL
These are larger proteins than albumin and important for immunologic responses (IgA, IgG, IgM, and IgE) but produced by B-lymphocytes.
Globulins
What do Globulins carry?
- Hormones
- Lipids
- Metals
- Antibodies
What would elevated Globulin levels indicate?
- Chronic Infections
- Liver Dz
- Rheumatoid Arthritis
- Myelomas
- Lupus
What would low levels of Globulins indicate?
- Immune Compromised
- Protein Malnutrition/Malabsorption
- Kidney dz
- Protein Losing Enteropathy
The liver must be able to use Vitamin K in the Coagulation Cascade to produce what Factors?
II, VII, IX, and X
This test is used to screen for INTRINSIC pathway factor inhibitors (Factors VIII, IX, XI, and XII) as well as common pathway factors (Factors II, V, and X)
Activated Partial Thromboplastin Time (aPTT)
This test is used to screen for EXTRINSIC pathway of coagulation (Factors I, II, V, VII, and X). It also measures the Vitamin K Status (Factors II, VII, IX, and X)
Prothrombin Time (PT)
Normal Range for PT
12.7-15.4 seconds
This test accounts for variations between different manufacturer lots of tissue factor.
INR
Normal Range for INR
0.9-1.1
Meaning of Prolonged PT-INR
> 80% of liver synthetic capacity is lost
- Clotting Factors made by the liver are low (Factor VII has a half-life of about 6 hours)
In Acute Liver Dz, the PT may be _______ and as the patient recovers, the PT becomes _______.
Prolonged; normal
Causes of Prolonged PT
- Chronic Cholestasis or Fat Malabsorption from Pancreatic or SB Dz
Bilirubin Metabolism Process
- Macrophages break down senescent RBCs in the spleen into globin and heme moieties
- Globin is catabolized to amino acids and the heme (porphyrin) to biliverdin and unconjugated bilirubin, which uses albumin as carriers
- In liver, there are three steps
a. Uptake by the liver hepatocytes after dissociation with albumin
b. Conjugation with glucoronic acid
c. Excretion of conjugated bilirubin into the bile
d. Conjugate bilirubin can be excreted unchaged in the stool
e. It can also be converted to urobilinogen by commensal bacteria in the distal SB and will:
- - be reabsorbed and enter portal circulation
- - be reabsorbed into portal circulation and by the liver and re-excreted into the bile
- - bypass the liver and be excreted by the kidneys as urine.
Normal Range of TBR (Total Bilirubin)
0.3 - 1.3 mg/dL
Two forms of Bilirubin
- Unconjugated (Indirect)
2. Conjugated (Direct)
Normal Range of Unconjugated Bilirubin
0.2 - 0.9 mg/dL
Normal Range of Conjugated Bilirubin
0.1 - 0.4 mg/dL
How do you calculate Indirect/Unconjugated Bilirubin?
***LFTs only show Conjugated/Direct and Total BR
IBR = TBR - DBR
T/F: Hyperbilirubinemia can occur as Indirect or Direct
True
T/F: Only Indirect/Unconjugated Hyperbilirubinemia can cause Jaundice.
False, Indirect or Direct Hyperbilirubinemia can cause Jaundice
When you see someone with Jaundice, what are you thinking?
Hyperbilirubinemia
What are the best places to look for Jaundice?
- Sclera (first)
- Skin
- Mucous Membranes (under tongue, hard palate)
TBR in Jaundice is about
2.0 - 3.0 mg/dL (2-3 x nl)