1. BILIRUBUN METABOLISM AN OVERVIEW
Good reference site for abnormal liver function test info.

2. FATE OF RED BLOOD CELLS Life span in blood stream is 60-120 days
Senescent RBCs are phagocytosed and/or lysed
Normally, lysis occurs extravascularly in the reticuloendothelial system (mainly spleen) subsequent to RBC phagocytosis
Lysis can also occur intravascularly
(in blood stream)

3. NORMAL BILIRUBIN METABOLISM Unconjugated = Fat soluble Conjugated = Water soluble

4. HYPERBILIRUBINEMIA
Increased plasma concentrations of bilirubin (> 3 mg/dL) occurs
when there is an imbalance between its production and excretion
Recognized clinically as jaundice

5. Prehepatic (hemolytic) jaundice
Results from excess production of bilirubin (beyond the livers ability to conjugate it) following hemolysis
Excess RBC lysis is commonly the result of autoimmune disease; hemolytic disease of the newborn (Rh- or ABO- incompatibility); structurally abnormal RBCs (Sickle cell disease); or breakdown of extravasated blood
High plasma concentrations of unconjugated* bilirubin (normal concentration ~0.5 mg/dL)
*Fat soluble

6. Intrahepatic jaundice
Impaired uptake, conjugation, or secretion of bilirubin
Reflects a generalized liver (hepatocyte) dysfunction
In this case, hyperbilirubinemia is usually accompanied by other abnormalities in biochemical markers of liver function

7. Posthepatic jaundice Caused by an obstruction of the biliary tree
Plasma bilirubin is conjugated, and other biliary metabolites, such as bile acids accumulate in the plasma
Characterized by pale colored stools (absence of fecal bilirubin or urobilin), and dark urine (increased conjugated bilirubin)
In a complete obstruction, urobilin is absent from the urine

8. Diagnoses of Jaundice AST (SGOT)/ ALT (SGPT) = Transaminases
ALP = Alkaline Phosphatse

9. Common, particularly in premature infants
Neonatal Jaundice
Common, particularly in premature infants
Transient (resolves in the first 10 days)
Due to immaturity of the liver enzymes
High levels of unconjugated bilirubin are toxic to the newborn – cause a type of mental retardation known as kernicterus
Jaundice within the first 24 hrs of life or which takes longer then 10 days to esolve is usually pathological and needs to be further investigated
Common, particularly in premature infants
Transient (resolves in the first 10 days)
Due to immaturity of the enzymes involved in bilirubin conjugation
High levels of unconjugated bilirubin are toxic to the newborn –
due to its fat solubility it can cross the blood-brain barrier and cause a type
of mental retardation known as kernicterus
If bilirubin levels are judged to be too high,
then phototherapy with UV light is used to convert
it to a water soluble, non-toxic form
If necessary, exchange blood transfusion
is used to remove excess bilirubin
Phenobarbital is oftentimes administered to
Mom prior to an induced labor of a
premature infant – crosses the placenta and induces the synthesis of UDP glucuronyl transferase
Jaundice within the first 24 hrs of life or which
takes longer then 10 days to resolve is usually
pathological and needs to be further investigated

10. Regulation of iron metabolism

11. Overview Patterns of Liver damage Review of individual tests
Appraise synthetic function
Non-hepatic causes of abnormal tests
Synthesize an approach to evaluation

12. What does the Liver do? A LOT! Detoxifies Poisons
Stores and Mobilizes Energy
Controls Blood Sugar (Glucose)
Regulates Glycogen
Regulates Fat Storage
Aids Digestion
Produces Bile
Regulates Blood Clotting
Manufactures
Clotting factors
Other Blood Proteins
Produces Hormones
Manufactures Cholesterol 
Filters Blood
Detoxifies Poisons
Externally-Derived Poisons
Alcohol
Byproducts of Metabolism
Bilirubin
Breaks down Drugs
Produces Vitamins
Vitamin D
Stores Minerals
Iron
Produces Essential Immune System Factors
Monitors, as Well as Manufactures, Countless other Blood Proteins, to Maintain the Proper Levels of Numerous Chemicals in the Body

13. Liver Function Key Points
Produces bile
Produces proteins
Albumin
Clotting factors
Liver does TOO much for any single test or set of test to determine
Focus on the basic test themselves and recognition of basic patterns

14. Markers of Hepatocellular Injury
Hepatocytes are damaged so they leak – so these enzymes are HIGH
Aspartate aminotransferase
(AST/ SGOT)
Alanine aminotransferase
(ALT/ SGPT)
Lactate dehydrogenase (LDH)

15. AST:ALT ratio Alcoholic hepatitis
Ratio is >1 90% of the time – often 2:1
Mechanism thought to be related to B6 depletion in alcoholics which leads to disrupted ALT synthesis and therefore decreased levels.
This is NOT SPECIFIC!!
Viral Hepatitis: Both ALT AND AST elevated
Ratio < 1 70% of the time
Mechanism unclear

16. Causes of Hepatocellular Damage
A Autoimmune hepatitis – ANA, Anti-smooth muscle ab (ASMA), Anti-Liver and Kidney Mitochondrial Ab. HEP A
B Hepatitis B
C Hepatitis C
D Drugs or toxins
E Ethanol / Hep E (Pregnancy)
F Fatty liver
G Growths (i.e., tumors)
H Hemodynamic disorder
(congestive heart failure or “shock liver”)
I Inborn errors - iron (hemochromatosis),
copper (Wilson's disease) or alpha1-antitrypsin deficiency

17. Level of Elevation
Giannini, E. G. et al. CMAJ 2005;172:

18. Key points AST and ALT elevations infer HEPATOCELLULAR DAMAGE
NON-SPECIFIC TEST with other causes that can lead to elevation
Levels in the 100’s ETOH, 1000’s viral, and 10,000’s toxin related.
Ratio can SUGGEST but not diagnose alcoholic hepatitis

19. Markers of Cholestasis/Obstruction
Cholestasis (lack of bile flow) results from the blockage of bile ducts or from a disease that impairs bile formation in the liver itself. Back leads to GRADUAL increase in enzymes over the course of days.
Alkaline phosphatase (ALP)
Gamma-glutamyltransferase (GGT)
Bilirubin

20. ALP Originates primarily in Bone and Liver
Other sources include intestine, kidney, placenta.
Isoenzymes can determine Bone vs Liver
May lag behind symptoms in rising.

21. GGTP (gamma glutamyl transpeptidase):
elevated in bile duct disease and alcoholism.

22. Causes of Cholestasis Obstruction Intrahepatic
Primary Biliary Cirrhosis – young females. Test: Anti-Mitochondrial Ab (AMA)
DRUGS – any number of medications, particularly antibiotics and anti-seizure
Any Hepatocellular damage (CONFUSED?
The hepatocellular can cause cholestatis, but the necrosis is greater)
Critical illness
Extrahepatic
Common duct obstruction (stone/Tumor)
Primary Sclerosing Cholangitis – More often males with IBD
Pancreatic head obstruction (Stone/Tumor)
Differentiate – use U/S to look at common bile duct dilation.
If non-diagnostic do ERCP then liver bx.

23. Bilirubin Fractions Present in Blood and Urine  
In Serum As:
Measured As:
Present in Urine
Unconjugated
(90%)
Albumin-bound
Indirect-reacting bilirubin
Never
Conjugated
Unbound
Direct-reacting bilirubin
Yes, when serum bilirubin exceeds 3-4 mg/dL

24. ACUTE ALCOHOLIC HEPATITIS
Pattern of liver test abnormality is hepatocellular
AST level is higher than the ALT level but rarely exceeds 400 IU/mL
AST is typically in the
100 IU/mL to 200 IU/mL range,
even in severe disease, and
The ALT may even be normal,
even in severe cases
“In alcoholic hepatitis AST:ALT ratio is 2:1”

25. Jaundice

26. Hyperbilirubinemia (Jaundice)
Prehepatic
(Hemolysis)
Posthepatic
Bile Duct Obstruction
Pancreatic Head CA
Hepatic
Genetic defects,
primary liver disease
Unconjugated Bilirubin
Mixed
Conjugated Bilirubin

27. Key Points
ALP and GGT combined are markers of cholestasis, but other things can make them rise.
2 types of Bilirubin, only conjugated excreted in urine
Cholestasis can be extra or intrahepatic – remember how to differentiate

28. LIVER FUNCTION TESTS Protein production Albumin Clotting Factors
Total protein production

29. Albumin 65% of serum protein ½ Life = 3 weeks
Low levels can correlate with chronic liver dysfunction.
Other reasons to be low?
Decrease production
Malnutrition
Chronic Inflammation
Increased Loss
Kidney – Nephrotic Syndrome
GI tract – Protein-losing enteropathy
Skin – Severe burn

30. A/G RATIO:
The value of the A/G ratio is not precise due to the countless number of variables in the fractions (Total Globulins and Albumin) associated with various metabolic states.
Abnormal A/G ratios usually reflect a general index of liver dysfunction.

31. Clotting Factors Most clotting factors are synthesized in the liver
½ shorter than Albumin
Prothrombin Time (PT) is a good functional test – but usually use INR to correct for lab variability
PT/INR PROLONGED in liver disease

32. Clotting Factor
Chronic cholestatic disease often have increased INR– Why?
Vit K def
Vit K Fat soluable
Cholestatic/obustructive so not enough bile secretion so not enough Vit K absorption
How to differentiate Vit K def from Decreased synthesis?
Give Vit K (take hours to correct)
Factor V NOT Vit K dependent so can be checked directly

33. Key Points The only liver FUNCTION test are test of PROTEIN PRODUCTION
Low albumin due to liver dysfunction implies CHRONIC (>3 week) liver damage
Always differentiate Vit K Def from Decreased liver synthesis in pt with cholestatic disease

34. Further Testing Ultrasound
Good to visualize large bile ducts and large masses. Cheap. Non-invasive
Use: Obstruction
ERCP (Endoscopic Retrograde Cholangio Pancreatography)
Visualize smaller bile ducts, ampulla of Vater, and head of pancreas. Provides t issue. Expensive. Highly invasive
Liver Biopsy (rarely done)
See hepatic pathology, particularly of the hepatocytes. Gold Standard. Expensive. Invasive
Use: Hepatocelluar

35. Overview of Approach to Liver Tests
Think of NON-hepatic causes for abnormalities
Look at pattern – cholestatic (hepatobiliary) vs hepatocellular
Look at tests of FUNCTION for duration of dysfunction
What is your DDx?
What further testing is needed?
See

36. Caveats of Liver ‘Function’ Tests
There is NO PERFECT TEST
A group of tests is needed in order to ‘infer’ functional liver status.
Mixed injury/obstruction patterns are common in REAL LIFE !!
DO NOT assume that a NORMAL test result indicates absence of liver disease. (example: AST & ALT can be normal in End Stage Cirrhosis.)

37. Hepatitis A Serology

38. Anti-HBsAg
HBsAg
HBeAg
Anti-HBcAg
Anti-HBeAg
HBV DNA

39. Hepatitis B http://en.wikipedia.org/wiki/Hepatitis_B
HBsAg is the surface antigen of the Hepatitis-B-Virus (HBV). It indicates current Hepatitis B infection.
HBcAg (core antigen) is a hepatitis B viral protein.[1][2] It is an indicator of active viral replication; this means the person infected with Hepatitis B can likely transmit the virus on to another person (i.e. the person is infectious). Multiple protein products can be produced from the same DNA sequence. When "ORF Core" and "Pre C" are translated together, the result is "HBeAg".
Hepatitis B vaccine is a vaccine developed for the prevention of hepatitis B virus infection. The vaccine contains one of the viral envelope proteins, hepatitis B surface antigen (HBsAg). A course of three (3) vaccine injections are given with the second injection at least one month after the first dose and the third injection given six months after the first dose.[1] Afterward an immune system antibody to HBsAg is established in the bloodstream. The antibody is known as anti-HBsAg. This antibody and immune system memory then provide immunity to hepatitis B infection.

40. USA: HCVGenotype distribution

41. Why Genotype? · Genotypes 1, 2 and 3 =
North America and Western Europe
· Genotype 4 =
Africa, Egypt and the Middle East, but is increasingly seen in some parts of Europe
·Genotype 5 = Africa and the Middle East
· Genotype 6 = Southeast Asia
· Genotype 7 = Central Africa
2 and 3 are more likely to rsvp to therapy than the others. Current tx is interferon combined with….? Follow the treatment wih the viral load test to measure # of copies made by virus.
Only 23% of Hep C patients can expect a cure in the US.

42. Why Genotype? 1. Those with genotypes 2 and 3:
Respond better (require only 24 week therapy)
2. Genotype 1 to respond poorly to therapy with-
alpha interferon or the combination of alpha interferon and ribavirin.
3. A 48-week course of combination treatment is typically adequate for those with genotype 1.
4. Data are mixed concerning genotype 4, though its response somewhere in between the response of genotypes 2 and 3, and genotype 1.
5. Treating genotype 5 shows that its response to combination treatment is similar to those with genotype 1.
6. genotype 6 lies at an intermediate level, between that seen with genotype 1 and genotypes 2 or 3.
7. Since it has just recently been discovered as having a distinct genetic make-up, the response to standard combination therapy is not yet established for genotype 7.
1. Those with genotypes 2 and 3 are almost three times more likely than patients with genotype 1 to respond to therapy with alpha interferon or the combination of alpha interferon and ribavirin.
2. A 24-week course of combination treatment is typically adequate for those with genotypes 2 and 3.*
3. A 48-week course of combination treatment is typically adequate for those with genotype 1.*
4. Data are mixed concerning genotype 4, though its response to combination treatment seems to be somewhere in between the response of genotypes 2 and 3, and genotype 1.
5. Recently published research on treating genotype 5 shows that its response to combination treatment is similar to those with genotype 1. However, previous results show that genotype 5 appears to be an easy to treat virus with response rates similar to those of genotypes 2 and 3 after a 48-week course of therapy.
6. Preliminary study results show that the response to treatment in those with genotype 6 lies at an intermediate level, between that seen with genotype 1 and genotypes 2 or 3.
7. Since it has just recently been discovered as having a distinct genetic make-up, the response to standard combination therapy is not yet established for genotype 7.

43. USA: Prev:4 million Incidence:35,000 to 185,000 Deaths: 10,000-20,000

44. Prevalence by Age & Ethnicity USA

45. Hepatitis C

46. VIRAL LOAD TESTS Measures number copies made by a virus
Reported as ‘high’ or ‘low’
High: More than 2 million copies
Low: Less than 2 million copies
?Log drop: A 10 fold change- take 0ne zero off the end of starting number for each ‘log drop’/’log kill’

47. RIBA Recombinant Immunoblot Assay
The EIA anti-HCV reactivity could represent a false-positive reaction, recovery from hepatitis C, or continued virus infection with levels of virus too low to be detected
If the immunoblot test for anti-HCV is positive, the patient has most likely recovered from hepatitis C and has persistent antibody without virus.
If the immunoblot test is negative, the EIA result was probably a false positive.

48. PCR (Polymerase Chain Reaction) Amplification
PCR amplification can detect low levels of HCV RNA in serum.
Testing for HCV RNA is a reliable way of demonstrating that hepatitis C infection is present and is the most specific test for infection.

49. Genotyping and Serotyping of HCV
6 known genotypes and more than 50 subtypes of hepatitis C
Helpful in epidemiology and deciding response to therapy
Genotypes 2 and 3 are almost three times more likely to respond to therapy with alpha interferon or the combination of alpha interferon and ribavirin.

50. ELISA
Enzyme-Linked ImmunoSorbent Assay, or ELISA, is a biochemical technique used mainly in immunology to detect the presence of an antibody or an antigen in a sample.

51. 3 ways to test viral loads:
PCR measure the amount of HCV RNA in the blood (can measure very small loads as low as 50 IU/mL)
bDNA (Branched –chain DNA)- only measures medium loads above 500 IU/mL
TMA (Transcription-mediated amplification) can measure very small amounts (5-10 IU/mL)

52. Remember! Antibodies (Ab) suggests immune response
IgM-Ab means acute infections
IgG-Ab means NO active infection

53. Immunoassay Antibody (Ab) or antibodies to its antigen (Ag)
A test that measures the concentration of a substance in a biological liquid:
typically serum or urine,
uses the reaction of an
Antibody (Ab) or antibodies
to its antigen (Ag)

54. X Anti-HBs –ve; HBsAg+; Anti HBc Ag +ve; Anti-HBc IGM Ab +ve Suggests:
A. Acute hepatitis B
B Chronic hepatitis B-Low infectivity
C. Chronic hepatitis B-High infectivity
D. Immunized against HBV infection

55. X Anti-HBs -ve; X Anti-HBc IGM Ab –ve; HBsAg detected;
Anti HBc Ag +ve;
X Anti-HBc IGM Ab –ve;
Anti- HBe Ab +ve;
Suggests:
A. Acute hepatitis B
B Chronic hepatitis B-Low infectivity
C. Chronic hepatitis B-High infectivity
D. Immunized against HBV infection

56. X HBsAg not detected; Anti-HBs +ve; X Anti-HBc IGM Ab –ve; Suggests:
A. Acute hepatitis B
B Chronic hepatitis B-Low infectivity
C. Chronic hepatitis B-High infectivity
D. Immunized against HBV infection

57. HBsAg detected; X Anti-HBs not detected; X Anti-HBc IGM Ab not detected; X Anti-HBe Ag not detected
Suggests:
A. Acute hepatitis B
B Chronic hepatitis B-Low infectivity
C.Chronic hepatitis B-High infectivity
D.Immunized against HBV infection

58. HBsAg not detected;
Anti-HBs not detected;
Anti-HBc IGM Ab not detected;
Suggests:
A. Acute hepatitis B
B Chronic hepatitis B-Low infectivity
C. Chronic hepatitis B-High infectivity
D. Immunized against HBV infection
E. Susceptible to HBV infection

59. PANCREATIC DATA

60. PANCREATIC CANCER ENDOCRINE- INSULINOMA
EXOCRINE- HEAD/BODY/ TAIL/AMPULLA
OBSTRUCTIVE “PAINLESS” JAUNDICE/ WEIGHT LOSS
Fourth leading cause of cancer death
DIAGNOSIS BY IMAGING

61. USEFUL BIOCHEMISTRY CMP
CA-19-9/ CEA 19 Useful in follow up after therapy but not for diagnosis

62. PANCREATIC DISEASES
Endocrine -- which produce the hormones insulin and glucagon
Exocrine -- which make powerful enzymes to digest fats, proteins, and carbohydrates

63. PANCREATITIS ALCOHOL T2 DIABETES CYSTIC FIBROSIS
PANCREATIC INSUFFICIENCY

64. ? PANCREATIC INSUFFICIENCY
Lack of digestive enzymes:
presents with symptoms of malabsorption,
malnutrition,
vitamin deficiencies,
weight loss, and is often associated with steatorrhea (loose, fatty, foul-smelling stools).
Diabetes may also be present in adults with pancreatic insufficiency.

65. ?Tests Fecal Fat- look for fat globules Trypsin-stool trypsin levels
Trypsinogen (serum)
Imaging: MRI Studies/ ERCP

66. Pancreatitis Amylase- increase after 2-12 hrs peaks at 12-72 hrs
Lipase- increase after 4-8 hrs peaks at 24 hrs
Trypsin/Trypsinogen
Complete Blood Count (including white blood cell count)
Comprehensive Metabolic Panel (Bilirubin, liver function tests)
Glucose
Calcium
Magnesium
C-Reactive Protein