Page 437 - Concise Pathology for Exam Preparation ( PDFDrive )

422 SECTION II Diseases of Organ Systems

(iii) AST on the other hand is also found in heart and muscle. Normal value is
0–40 IU/L.
(iv) Aminotransferase levels are useful in differentiating between hepatocellular
and obstructive jaundice.
(v) Marked elevation is seen in severe viral hepatitis (Hepatitis A, B and C),
drug-induced injury (acetominaphen toxicity) and circulatory abnormalities
(shock liver).
(vi) Mild elevation is seen in neonatal hepatitis, extrahepatic biliary atresia, fatty
liver, cirrhosis, NASH (nonalcoholic steatohepatitis) and drug toxicity.
(b) Alkaline phosphatase or ALP (indicator of cholestasis)
(i) Serum ALP activity is primarily derived from liver and bone. Normal level is
3–13 KA units.
(ii) In hepatocellular jaundice, very little ALP is liberated from the cells and the
rise in ALP is less than three folds.
(iii) In obstructive jaundice, due to obstruction of biliary tract, all the new ALP that is
synthesized, escapes into the blood. Hence, serum ALP levels are markedly raised.
Causes of raised ALP:
• Obstructive jaundice
• Metastatic bone tumours
• Hyperparathyroidism
• Paget disease
• Pregnancy
• Rickets
• Tumours of GIT
(c) Gamma-glutamyl transpeptidase or GGTP (indicator of cholestasis)
(i) If the source of ALP is not clear, the levels of two enzymes, gamma-
glutamyltransferase and 5’ nucleotidase can be determined (more specific
for liver). Raised levels occur in biliary obstruction and parenchymal damage.
(ii) Serum levels rise in acute and chronic alcoholism (raised levels suggest pro-
longed intake of more than 60 g alcohol/day).
5. Plasma proteins (indicator of synthetic ability):
(a) Albumin is synthesized in liver. Normal serum albumin level is 3.5–4.5 g/dL. In
chronic liver diseases like cirrhosis and chronic active hepatitis, serum albumin is
low (,3 g/dL).
(b) Globulins are synthesized by the reticuloendothelial system. Normal serum globu-
lin level is 1.5–3 g/dL. Their levels rise in chronic liver disease. IgG is raised in
chronic active hepatitis and cryptogenic cirrhosis. IgA is raised in alcoholic liver
disease. IgM is raised in primary biliary cirrhosis.
6. Coagulation factors (indicator of synthetic ability):
(a) Liver synthesizes 11 coagulation factors and activates some in the presence of vitamin K.
(b) Prothrombin time (PT) is prolonged in liver disease (PT depends on factors I, II, V,
VII and X, and gets prolonged when the plasma concentration of any one of these
falls below 30% of the normal).
7. Bromsulphthalein (BSP) clearance: BSP clearance is delayed in Dubin–Johnson
syndrome.
8. Other tests for liver function:
(a) Serology for viral hepatitis (B and C, CMV and EBV)
(b) Autoantibody screen for autoimmune hepatitis and biliary cirrhosis (antimitochondrial
antibody, antismooth muscle antibody and antinuclear antibody)
(c) Serum ferritin and transferrin saturation for haemachromatosis
(d) a-fetoprotein levels for hepatocellular carcinoma
(e) Copper/ceruloplasmin levels for Wilson disease
(f) a-1 antitrypsin levels for a-1 antitrypsin deficiency
(g) Noninvasive tests like ultrasound and CT that help in detecting structural abnor-
malities
(h) Doppler test can be used to assess vasculature-related abnormalities
(i) Liver biopsy for definitive histopathological diagnosis of inflammatory and neo-
plastic pathology

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