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Reviewing the chemistry panel: Liver cases (Proceedings)

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Aug 01, 2010

The Serum Chemistry Profile
5 Components:
      1. Electrolytes / Acid-Base
      2. Kidney
      3. Glucose
      4. Proteins
      5. Muscle enzymes
      6. Liver parameters

Liver Components

      1. Enzymes
          • SDH
          • AST
          • GGT
          • SAP
      2. Functional components
          • BUN
          • Glucose
          • Albumin
          • Iv. Bilirubin

Enzymes

      Hepatocellular enzymes:

1. SDH
     • Short half-life
     • Cytosolic (means necrosis present)
     • Liver specific

2. AST
     • Intermediate half-life
     • Cytosolic (means necrosis present)
     • Not specific: also from muscle

Biliary:
1. GGT
          • Very long half-life (several days) and upregulated
          • Secreted (It means the ducts have been irritated/inflamed, Increase does not mean necrosis of cells)
          • Biliary-specific (nearly...also found in pancreatic ducts)

2. SAP (serum alkaline phosphatase)
          • Intermediate half-life
          • Secreted (Increase means cells are irritated, not necessarily necrotic)
          • Found in several other tissues:
          • SAP also from bone, placenta, inflammatory cells...

Clinical Relevance
          • SDH tells what is on-going (current status)
          • GGT stays increased for weeks after insult
          • SDH and GGT confer specificity
               o indicate liver/biliary disease
          • SDH and AST indicate hepatocellular necrosis
          • GGT and SAP indicate biliary disease

Functional Indicators in the Chem Panel

These analytes are made by the liver:

Liver dysfunction / failure:
          • BUN ↓ - except neonate
          • Glucose ↓ – late finding
          • Albumin ↓ – late finding; < 20 % of cases
          • Cholesterol ↓

Bilirubin
          • Indirect (unconjugated)
          • Direct (conjugated)

One or both increase with liver disease

Direct fraction = 25 % of the total BR strong evidence of biliary disease