Gastric Fluid

• Gastric Fluid

  • determines whether or not a patient can secrete gastric fluid
  • measures amount of gastric acid that can be secreted by one with ulcer symptoms
  • help determine the disturbed function of the GI system
• Cells of the Stomach

  1. Parietal cells
  2. chief cells
  3. specialized G cells
• Parietal cells

  • produces HCl and intrinsic factor
  • HCl - converts pepsinogen to pepsin that catalyzes the digestion of protein
  • Intrinsic Factor - responsible for vitamin B12 absorption
  • parietal cells will secrete HCl in response to Gastrin stimulation
• Chief cells

  produces pepsinogen that will be converted to pesin whenever HCl is present
• Specialized G cells

  produces gastrin that stimulates parietal cell to produce HCl
• Specimen Collection: Fasting Residual Volume

  • conventional units: 20 - 100mL
  • factor: 0.001
  • recommended SI units: 0.02 - 0.10L
• Specimen Collection: pH

  • conventional units: < 2
  • factor: 1
  • recommended SI units: < 2
• Specimen Collection: BAO

  • conventional units: 0 - 6 mEq/hr
  • factor: 1
  • recommended SI units: 0 - 6 mmol/hr
• Specimen Collection: MAO (after histamine stimulation)

  • conventional units: 5 - 40 mEq/hr
  • factor: 1
  • recommended SI units: 5 - 40 mmol/hr
• Specimen Collection: BAO/MAO Ratio

  • conventional units: < 0.4
  • factor: 1
  • recommended SI units: < 0.4
• Gastric juice is obtained by insertion of a gastric tube into the stomach

  • gastric tube
  • levin tube: passed through the nose
  • rehfuss: passed through the mouth
  • disposable plastic tubes are usually employed
• Specimen

  fasting specimen, few mL to 50mL; average of 30mL
• Normal appearance of gastric specimen

  pale gray with mucus snd no food particles
• Types of specimen:

  1. Basal Acid Output (BAO)
  2. 1 hour collection
  3. requires 12 hour fasting
  4. no gastric stimulant needed
  5. Maximum Acid Output (MAO)
  6. 1 hour collection (four 15 minute specimens)
  7. with gastric stimulant
• GASTRIC STIMULANTS: TEST MEALS

  1. Ewald’s meal: bread and water or weak tea
  2. Boas meal: oatmeal, meal for detection of lactic acid
  3. Riegel’s meal: mashed potatoes, broiled beefsteak, bouillon
• GASTRIC STIMULANTS: Chemicals

  1. Pentagastrin - most preferred, it resembles true gastrin
  2. Histamine
  3. Histalog
  4. Insulin x assess successful vagotomy procedure
• GASTRIC STIMULANTS: SHAM FEEDING

  • fictitious feeding
  • sandwich is chew and then spit out
• Lactic Acid Test

  1. Modified Uffelman’s

  • Reagents: FeCl3 + phenol
  • Endpoint: Yellow

  1. Strauss

  • Reagents: FeCl3 + ether
  • Endpoint: Yellow

  1. Kelling’s

  • Reagent: FeCl3
  • Endpoint: Yellow
• Quantitative Test for Gastric Acidity: Free HCl

  • Topfer's method
  • Titrate with NaOH 
  • pH indicator: dimethyl aminoazobenzol
  • Endpoint: Canary yellow
  • Normal value: 25-50 degrees or 0.1 or 0.2 HCL
• Quantitative Test for Gastric Acidity: Total Acidity

  • Titrate with NaOH
  • Ph indicator: phenolphthalein
  • Endpoint: Faint pink
  • Normal value: 50 -75 degrees
• Quantitative Test for Gastric Acidity: Combined HCl (bound to proteins)

  • Titrate with NaOH 
  • pH indicator: sodium alizarin
  • Endpoint: Violet
  • Normal value: 10 - 15 degrees 
• Qualitative Test for Free HCL: 

  1. Dimethylaminoazobenzol: Reagent: alcohol solution = (+) cherry red
  2. Gunzberg’s: Reagent: phloroglucin, Vanillin, Alcohol = (+) Purple red color
  3. Boas: Reagent: resorcinol, cane sugar, alcohol = (+) Purple red color
• DIAGNEX BLUE TEST / TUBELESS TEST

  • Specimen: Urine
  • Principle: an ion exchange resin (Amberlite cation), coupled with a dye, azure blue, is given by mouth after caffeine stimulation. In the presence of free HCL, the azure blue is released from combination with the resin in exchange for hydrogen ions. The azure blue is rapidly adsorbed from the intestines and travels in the blood to the kidneys and is excreted in urine. The appearance of azure blue is then an indication that free HCL is present in the stomach.
  • Stimulant used: Test meals (Henry's) 1, Histamine (other books)
• 1. Euchlorhydria

  • Normal free HCL

  1. Hyperchlorhydria

  • Increased free HCL
  • Peptic ulcer

  1. Hypochlorhydria

  • Gastric fluid pH >3.5 but falls after gastric stimulation
  • Decrease free HCL
  • Carcinoma of stomach

  1. Achlorhydria

  • Gastric fluid pH >3.5 and does not fall even after gastric stimulation
  • Absence of free HCL
  • Pernicious Anemia

  1. Zollinger Ellison syndrome

  • Elevated Gastrin levels
  • Elevated BAO/MAO results (highest elevation)

  1. Pernicious anemia

  • Shows a zero BAO/MAO results
  • Achlorydia (absence of free HCL)