Page 378 - The Veterinary Laboratory and Field Manual 3rd Edition

Clinical chemistry 347

in a serum sample increases and is free to form 1 sodium nitroprusside 3 g (10.07 mmol)
complexes with iodine. 2 ammonium sulphite 100 g (756.8 mmol)
3 sodium carbonate (anhydrous) 50 g (471.7
rEaGEntS rEquIrEd mmol).
Mix 6.7 g (52.8 mmol) of iodine (I) and 13.3 g
(80.12 mmol) of potassium iodide (KI) together, MEtHod
add a small amount of water while stirring and 1 Reagent powder is sprinkled on a white por-
continue until dissolved to make solutions up celain tile.
to 100 ml. 2 A drop of serum (0.04 ml) is deposited on the
powder using a Pasteur pipette.
MEtHod 3 The reaction is read after 5 min.
• Add one drop of the reagent to 1, 2 and 4 4 A pink colour indicates a positive reaction.
drops of serum on a white porcelain tile.
Allow to stand for 2 min then mix with a Estimation of serum bilirubin
tooth pick. Examine after 30 min and assess
the degree of precipitation. PrIncIPLE
• A positive reaction is shown by the presence Ferric chloride will oxidize bilirubin to bili-
of a precipitate. verdin producing a greenish blue colour. An
• If only the 1 : 1 sample has reacted this indi- intense blue/green colour reaction between the
cates sub-clinical liver damage. test serum and Fouchet’s reagent indicates the
• If the 1 : 2 or 1 : 4 samples show a precipitate presence of excess amounts of serum bilirubin.
this indicates clinical liver damage. However, this does not allow reliable distinc-
tion between bound and unbound forms of
Ideally serum samples should be submitted for bilirubin.
liver enzyme tests (AST/ALT) and further analy-
sis. If this is not available, supportive treatment FoucHEt’S rEaGEnt
for the animal should be recommended and Dissolve 25 g (153 mmol) trichloracetic acid in
repeat tests conducted after a few weeks to 100 ml of distilled water and add 10 ml of 10%
determine if the liver damage is progressive. (370 mmol/l) ferric chloride (FeCl ).
3
MEtHod
Rapid Spot test for blood ketones
1 On a white porcelain tile place a few drops
PrIncIPLE of serum and an equal number of drops of
This test relies on the fact that serum containing Fouchet’s reagent.
ketones will produce ammonia when react- 2 Mix well with a glass rod and examine for up
ing with the test reagent and turn the reagent to 5 min for the development of a blue/green
powder red. A positive reaction will only occur colour.
if the level of blood ketones is greater than 3 The interpretation of the result is outlined in
10 mg/100 ml. Table 7.5.

rEaGEnt
Grind the following together into a fine powder
using a mortar and pestle and store in a dark
stoppered bottle.

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