40
Reaction Sequence
Glucose (GLU)
Glucose is the principal source of energy in monogastric mammals. The circulating concentration in
the healthy animal is maintained within narrow limits.
Principal Reason for Performing the Test
To investigate carbohydrate metabolism.
Most Common Abnormality Indicated by the Test
Increased glucose—diabetes mellitus; glucocorticoid influence; epinephrine influence.
Sample Type and Precautions
For glucose determinations, the animal should have been fasted for 5–8 hours before sampling.
Hemolysis may affect glucose results.
For plasma samples:
Use only lithium heparinized samples. When blood is collected in
lithium heparin, it is important that the sample be centrifuged immediately after collection.
In this anticoagulant, glycolysis occurs quite rapidly in the presence of red blood cells
and the glucose concentration in the sample can diminish at up to 10% an hour at room
temperature. Remove plasma promptly from the red blood cells. Hemolyzed specimens
should not be used.
For serum samples:
Do not centrifuge serum samples until clotting is complete. Samples
must be centrifuged completely. Remove serum promptly from the clot to avoid metabolism
of glucose by the cells. A maximum of 30 minutes between drawing and separation from
the clot is recommended. Hemolyzed specimens should not be used.
Complementary Tests
When the patient is a diagnosed diabetic, glucose tests may be performed in isolation. It is,
however, useful to perform other tests for renal and hepatic function and lipid metabolism to
monitor secondary effects of poorly controlled diabetes. Because stress in companion animals,
particularly cats, can significantly raise glucose above the reference range, a fructosamine level
should be considered in suspected cases of diabetes mellitus. A concurrent urinalysis should also
be performed to evaluate for the presence of glucose and ketones.
Reaction Sequence
Inorganic Phosphate (PHOS)
Phosphorus plays a major role as a metabolic intermediate and is a constituent of nucleic acids,
phospholipids, and nucleotides. Phosphates are also important components of buffering systems
within the body fluids. Phosphate and calcium are absorbed in the small intestine. Absorption is
influenced by the presence of other minerals, nutrients, vitamins, and intestinal pH. Calcium and
phosphorous metabolism are interdependent.
Appendices
