1. Liver function tests measure three categories: direct hepatocellular damage, cholestasis, and the liver's synthetic ability. 2. Transaminases like AST and ALT are elevated with hepatocyte injury from conditions like hepatitis, toxic injury, or ischemia. One-third of hepatitis C patients can have normal transaminase levels. 3. Cholestasis is reflected in elevated bilirubin and alkaline phosphatase levels, which take longer to rise than AST/ALT in acute bile duct obstruction.

1. ABNORMAL LIVER
FUNCTION TESTS
Serina Farzin-Nasab, MD
Emory University
Family Medicine Residency Program

2. 3 Categories:
1- Direct hepatocellular damage (transaminases)
2-Cholestasis ( bilirubin, alkaline phosphates)
3-Liver’s synthetic ability ( albumin, PT)

3. Transaminitis
Hepatocyte necrosis leads to leakage of enzyme
 Hepatitis
 Toxic injury
 Ischemic injury

4.  Hep C: liver cell death by apoptosis
(programmed cell death) and by necrosis
 1/3 pt’s with Hep C have persistently normal
serum transaminases

5.  Levels of aminotransferases can rise in Severe
muscular exertion or other muscle injuries,
polymyositis
 Hypothyroidism

6. AST and ALT levels do not
follow a normal bell-shaped
distribution
AST and ALT are higher in
obese pt’s, males and
nonwhites ( blacks and
Hispanics)

7. Causes of Elevated ALT or AST Values in
Asymptomatic Patients
A) Autoimmune hepatitis
B) Hepatitis B
C) Hepatitis C
D) Drugs or toxins
E) Ethanol
F) Fatty liver

8. G) Growths (tumors)
H) Hemodynamic disorder (congestive heart failure)
I) Iron (hemochromatosis), copper (Wilson's
disease) or alpha1-antitrypsin deficiency
M) Muscle injury

9. Typical AST or ALT Values in Disease

10.  Cholestasis reflected in abnormal bilirubin and
AP levels
 In acute bile duct obstruction from a gallstone,
AST and ALT levels often reach 500 U per L or
more in the first hours , whereas AP and GGT
levels can take several days to rise.
MARKERS OF CHOLESTASIS

11.  Elevation of GGT alone results from enzyme
induction by alcohol or aromatic medicatios
 GGT is elevated in persons who drink 3 or more
per day

12. Direct/conjugated hyperbilirubinemia
 Conjugated bilirubin levels do not rise until the
liver has lost approximately half of its excretory
ability.
 The presence of conjugated bilirubin in the urine (
urine dipstick), is always indicative of
hepatobiliary disease .

13. Indirect/uncongealed Hyperbilirubinemia:
Gilbert syndrome
 Common benign inherited disorder
 Levels between 2 and 3 mg/d
 Patients develop detectable jaundice during
acute illness or starvation

14. Hemolysis
 Confirmed by an elevated retic count & increased
haptoglobin levels.
 In adults, no serious liver disease will
cause elevation of indirect bili alone without a
concurrent rise in direct bili levels.

15. AP
 Elevated levels are found in adolescents, children
(secondary to bone growth), and pregnant women
 Women with persistently elevated AP levels
primary biliary cirrhosis
 Confirmed by a serum antimitochondrial antibody
test

16. Hepatic Cause of elevatedAP
Hepatocellular disease (usually <3-fold
increase)
• Alcoholic hepatitis
• Viral hepatitis
• Fatty infiltration of liver
• Cirrhosis

17. Hepatic Cause of elevatedAP
Obstructive processes (usually >3-fold increase)
 Choledocholithiasis
 Cancer of head of pancreas
 Cholangiocarcinoma
 Cholestatic hepatitis

18. Hepatic Cause of elevatedAP
Infiltrative, neoplastic, Primary or metastatic
carcinomas (15- to 20-fold increase)
 Primary biliary cirrhosis
 Amyloidosis
 Hepatic congestion caused by heart disease
 Infectious mononucleosis

19. Hepatic Cause of elevatedAP
Medications:
Captopril
Erythromycin
Gold salts
Phenothiazines
Trimethoprimand-sulfamethoxazole
Anticonvulsants

20.  Increased synthesis of AP in Diabetes mellitus
 44% of patients with DM have increased AP

21. Common Non hepatic Causes of
Elevated GGT
 Acetaminophen overdose
 Acute myocardial infarction
 Acute pancreatitis
 Anticonvulsants (phenytoin, phenobarbital,
 carbamazepine)

22.  Brain tumor
 Diabetes mellitus
 Hyperthyroidism
 Infectious mononucleosis
 Epilepsy

23. Albumin
 An Index of liver synthetic capacity
 Low albumin level and no other LFT
abnormalities are likely to have a non hepatic
cause

24. Albumin
Non hepatic causes of low Albumin:
 Inflammatory states such as burns, trauma,
& sepsis
 Active rheumatic disorders
 Severe end-stage malnutrition
 Pregnancy
 Proteinuria

25. PT
 Does not become abnormal until more than
80%of liver synthetic capacity is lost
 Useful to be followed in acute hepatic failure
(Factor 7 has very short half life)

26. PT
 Vitamin K deficiency
 Chronic cholestasis or fat malabsorption
 A trial of vitamin K injections ( 5 mg /day SQ x 3
days) practical way to exclude vitamin K
deficiency
 PT should improve within a few days

27. Ammonia
 Concentrations are much higher in the brain than
in the blood and therefore do not correlate well
 It is not unusual for the blood ammonia to be
normal in a patient who is in a coma from hepatic
encephalopathy.

28. QUIZ
Other than hepatitis, causes of elevated
serum GGT include all of the following except:
A. Diabetes mellitus.
B. Hypothyroidism.
C. Brain tumor.
D. Infectious mononucleosis.
E. Acute myocardial infarction

29. Answer : B
Hyperthyroidism is associated with
elevated GTT

30. QUIZ
The greatest increase in serum alkaline
phosphatase is generally seen in a patient
with which of the following conditions?
A. Primary biliary cirrhosis.
B. Alcoholic hepatitis.
C.Viral hepatitis.
D. Fatty infiltration of the liver.
E. Cancer of the head of the pancreas

31. Answer: A
Primary billiary cirrhosis

32. QUIZ
In patients with viral hepatitis, the serum
AST level is usually higher than the serum
ALT level
A. True.
B. False

33. False

34. QUIZ
Normally, most of the total bilirubin is
conjugated.
A. True
B. False

35. False
70% of total Billi is non conjugated