1. Insulin Stimulation test
Insulin hypogycemia is a potent stimulus of acid secretion.
When blood sugar is < 50.0mg/dl (2.8mmol/L) vagus is stimulated by hypoglycemia.
This test is best limited to those patients suspected to have recurrent ulceration after vagotomy which was probably incomplete.

2. Plasma Gastrin Valuable in diagnosis of Zolliger- Ellison Syndrome.
Normal plasma concentration: 50 – 150pg/ml.
Zolliger- Ellison Syndrome: 1000 – 400,000pg/ml.
Not increased in simple peptic ulcer.
Increased in pernicious anemia.

3. Test for Occult blood in the feces
Definition: Tests to detect blood in feces in amounts or forms not observable on inspection are referred as occult blood test.
Normal blood loss in the feces 2.5ml/day by radiochrome studies. Blood may be introduced from mouth, around teeth, minor abrasion in the GI tract by roughage of food, hemoglobin, myoglobin, their breakdown products, peroxidases of plant & bacterial origin.

4. Benzedine test was commonly used, now prevented because of its carcinogenecity O-toluidine is used with three different concentrations: 4%, 1.2% & 0.4% in glacial acetic acid.
Principle:
hemoglobin & its derivatives
O-Toluidine
H2O2
H2O + O2
Coloured product
(Measured colorimetrically)

5. Test procedure
A small portion of feces mixed in 10ml DW & boil for a minute to destroy peroxidases. Mix fecal suspension + reagent (O-toluidine & H2O2)
Blue colour --- Positive test.
If a single concentration was used 1.2% recommended.
If all three used 1st 4% used, positive samples tried with 1.2%, still positive samples tried with 0.4%.

6. Reporting Negative -ve with 4% Weakly positive +ve only with 4%
Strongly positive
+ve with 4%, 1.2%, 0.4%

7. Interpretation
Test is mainly used in the diagnosis & treament of ulcers, cancer of stomach, gastritis, perpura, lesion in duodenum, small & large intestine.
In case of humorrhoids blood can be seen as streeks of fresh blood on the surface of feces confirmed by misroscopic examinations.
It is also useful practice to do the test on three successive days when the patient is on meat free diet.

16. Exocrine secretions of Pancrease
Inorganic Organic
NaHCO3(127mmol/L) α - amylase
Na+ ( mmol/L) Lipase
K+ ( mmol/L) Trypsin
Mg+, Ca+2, Zn+(less) Chymotripsin
Cl- (155mmol/L) Carboxipeptidase A & B
Ribonucleases
Deoxyribonucleases
Cholesterol esterases
Phospholipases

17. Tests in Pancreatic Diseases
Introduction
Measurement of total volume.
Concentration of HCO3-
Chemical & cytological examinations performed support suspicion of malignant neoplasm, but exact localization may be unknown.
Secretin/ CCK-PZ test

18. Amylase (AMS)
Tissue source: acinar cells of pancreas & salivary glands. Lesser concentration in skeletal muscle, small intestine, fallopian tube.
This is the smallest enzyme readily filtered through the renal glomerulus & appears in the urine.

19. Isoenzymes of AMS P-type: pancreatic
S- type: salivary, fallopian tube, lung
Isoenzymes of salivary origin migrate most quickly (S1, S2, S3), where as pancreatic origin move slower (P1, P2, P3).
AMS migrate in the regions corresponding to β to α-globulin regions of the protein.
P-type activity, specifically P3 in acute pancreatitis

20. Renal clearance of AMS × ×
Useful in detecting minor or intermittent in serum concentration.
Normal Values: < 3.1%
Acute pancreatitis: 8% - 9%
Also in burns, sepsis, diabetic ketoacedosis.
% AMS clearance UA SC × × =
100
Creatinine clearance SA UC

21. Lipase (LPS) Assay by titrimetric method:
Tissue source: primarily in pancreas, little in stomach & small intestine.
Classical Cherry-Crandall method used an olive oil substrate & measured the liberated FA by titration after 24h incubation. Trioline is one of the substance now used as a more pure form of TAG.
LPS +
triglyceride +
2H2O
2-monoglyceride
2-fatty acid
pH 8.6-9

22. Turbidimetric method
LPS
Fats in solution
Hydrolysed fat in solution
(cloudy emulsion)
(Fat particles disperse)
Rate of clearing of the fat in the solution is measured.

23. Interpretation Reference range: 0 – 1.0U/ml
This is exclusive for the diagnosis of acute pancreatitis.
Both AMS & LPS levels rise quickly, but LPS elevation persist for 5 days, whereas AMS only for 2 – 3 days.
Elevated also in penetrating duodenal ulcer, intestinal obstruction & acute cholecystitis.

24. In contrast to AMS levels, LPS levels are normal in conditions of salivary gland involvement.
Of the three LPS isoenzymes, L2 is thought to be most clinically specific & sensitive.