Labs

• AFP (Alpha-Fetoprotein)
  • <20?
  • Produced by yolk sac and fetal liver
  • Elevated in HCC, Metastatic liver cancer, liver cirrhosis, hepatitis, germ cell tumors, yolk sac tumors, ataxia telangiectasia, spherocytosis, pancreatic cancer,
  • False-Positive: gestational diabetes, cigarette smoking, race (higher in black women), viral hepatitis, pregnancy
  • ≥200 is 100% specific for HCC in Cirrhosis
• Albumin
  • Microalbumin: Creatine ratio in the urine
    • Best test to screen for initial stages of diabetic nephropathy
    • Dipstick on detects when protein ≥300mg/24h (microalbumin)
  • Hyperalbuminemia
    • 40% of calcium is bound to proteins (mainly albumin)
    • Associated with an increase in total calcium
    • Measure Ionized fraction of Calcium for accurate count
    • No symptoms usually
  • Hypoalbuminemia
    • Decreased in malnutrition, nephrotic syndrome, acute inflammation, protein-losing enteropathies
    • 1) Decreased Hepatic Synthesis
      • Cirrhosis
    • 2) Increased Urinary or GI loss
      • Nephrotic Syndrome:
        • Periorbital and pedal edema that may progress to generalized edema (anasarca), ascites, and pleural effusions
      • Protein Losing Enteropathy
        • Diarrhea
    • May develop severe intravascular hypovolemia due to over-diuresis and fluid movement into the interstitial spaces
• Bilirubin
  • Function clearance of liver
  • Increased Bilirubin (Jaundice) – Fractionate Bilirubin
    • Increased Direct Bilirubin
      • Obstructive (stone, cancer) or Dubin Johnson’s, Rotor
    • Increased Indirect Bilirubin
      • Hemolysis (bilirubin overproduction)
      • Gilbert Syndrome (defective uptake)
      • Crigler-Najjar or newborn (Glucuronyl transferase defect)
    • Obtain Liver Enzymes: Alkaline Phosphatase
      • Increased ALP (Biliary Pathology)
        • Increased GGT/ Increased AST/ALT (Ultrasound/CT)
          • Bile duct obstruction, IBD w/PSC
          • Metabolic Alkalosis in BDO
      • Mildly increased ALP
        • Increased GGT
          • Increased AST/ALT: Hepatocellular Disease
        • Normal GGT
          • Normal Calcium: Paget’s disease
  • Increased Conjugated Bilirubin
    • Can’t get rid of Bilirubin (extrahepatic dysfunction)
  • Increased Unconjugated Bilirubin
    • Body can’t conjugate bilirubin (hepatic dysfunction or RBC breakdown)
    • Hyperbilirubinemia and High LDH
      • Autoimmune hemolytic anemia
      • G6PD deficiency
      • Mechanical RBC destruction
      • Hereditary spherocytosis
      • B12/Folate Deficiency
  • Increased Direct/Conjugated Bilirubin + Cholesterol + alkaline phosphatase
    • Cholestatic pattern
      • Ultrasound (CT)
• BNP
  • Elevated in patients with kidney failure, old age, female
  • Reduced in patients with an elevated BMI
• CA 19-9
  • <40
  • Associated with Pancreatic cancer, biliary tract cancer
  • Colon, esophageal, hepatic cancers, Pancreatitis, cirrhosis
• CEA (Carcinoembryonic Antigen)
  • <2.5 in non-smokers, <5 in smokers, ≥10 is concerning for cancer
  • Associated with tumor burden in colorectal cancer
  • Primary ovarian cancer, Breast cancer, NSCLC, Thyroid cancer, cigarette smoking, cholecystitis, liver cirrhosis, pancreatitis, IBD, orlistat, lymphoma, melanoma, PUD, hypothyroidism, biliary obstruction
• Complement
  • Hypocomplementemia
    • Genetic
    • Consumption
    • Underproduction
      • Eclampsia, HELLP syndrome
    • SLE, Vasculitis, RA, infective endocarditis
  • Low C2 or C4: Genetic allele deficiency
  • C3: classical or alternative
  • C4: SLE (classical)
  • CH50: all components of classical
    • Screening for diseases states resulting in hypocomplementemia
• Creatine Kinase (CK)
• Creatine phosphokinase (CPK)
  • Released from muscle tissue as it is damaged
  • Polymyositis, dermatomyositis, inclusion body myositis, Duchenne and Becker Muscular dystrophy
• Ceruloplasmin
  • Low
    • High Urinary ceruloplasmin
      • Wilsons
• CRP/ESR
  • Erythrocyte Sedimentation Rate and C-reactive protein
  • MC APRs used
    • Helpful in determining disease activity and response to therapy
  • Not specific, sensitive with low to moderate pretest probability
    • ESR ≥ 100mm/hr: severe disease (malignancy, infection, vasculitis)
• Elevated Ammonia (Hyperammonemia)
  • MCC is hypovolemia
  • Medications
    • Valproic Acid, carbamazepine, salicylates, sulfadiazine
• Elevated BUN
  • Tube feeds
  • High Protein
  • Chemotherapy
  • Upper GI bleed
• Gamma-glutamyl transpeptidase (GGT)
  • More specific than ALP because it is not present in bone
    • Not specific for alcohol
  • Increased GGT + Alkaline Phosphatase
    • Biliary Pathology
• Iron
  • Ferritin = storage of iron
  • TIBC is always opposite of Ferritin
  • Transferrin = carrier
  • High Iron, Low Ferritin, Low Fe binding capacity
    • Hemochromatosis
• Increased Amylase
  • Pancreatic
    • Pancreatitis, pseudocysts, trauma, ERCP, CF, Carcinoma
  • Salivary
    • Parotitis, radiation, obstruction
  • GI
    • PUD, perforated bowel, Mesenteric ischemia, appendicitis, cholecystitis, celiac’s
  • Gyne
    • Ectopic, ovarian cyst, PID
  • Neoplasm
    • Multiple myeloma, Pheo
  • Other
    • Alcohol abuse, RF (cleared renally)
• Liver Damage
  • AST
  • ALT
  • Synthetic Liver Function (Severe)
    • PT – clotting factors by hepatocytes
      • Prolonged in vitamin K deficiency, warfarin, inherited or acquired factor deficiency, Antiphospholipid antibiody
    • Albumin – by hepatocytes
• Liver and Biliary Tree Damage
  • ALP – made in liver, bile duct, kidney, placenta
  • GGT – bile duct, liver, alcohol abuse
• Platelet Count
  • Normal (150k-400k)
  • <50K risk of surgical bleeding
  • <10k risk of spontaneous bleeding
• Rheumatoid Factor (RF)
  • RA but also in 10% of normal population
  • RA will have evidence of inflammation in the hands in feet
• Serum Chromogranin A
  • Well-differentiated neuroendocrine tumors
  • Carcinoid tumors, hyperthyroidism, chronic atrophic gastritis, chronic PPIs, SCLC
  • Less sensitive and specific than Serum Gastrin