Idexx VetTest User Manual

H Chemistry Description and Guide
Introduction to Biochemical Profiling
By performing appropriate biochemical tests on good quality samples, you can obtain
information that, when used with clinical findings, should assist you to make a more
accurate diagnosis and prognosis. Selecting the appropriate tests is crucial.
Single tests are helpful in a particular circumstance, such as following the course of
an identified disease or monitoring the effect of therapy. However, many individual
chemistry tests do not give information specific to any particular organ or system. A test
result may be indicative of change to a number of organs, or in one or more metabolic
systems. Chemistry results, therefore, must be considered in conjunction with other
test results and clinical findings. The use of multiple tests—or a profile—covering
several organ systems can be very helpful when it is difficult to reach a diagnosis from
the clinical signs alone. The following sections discuss enzymes, and each of the
chemistries offered on the IDEXX VetTest* Chemistry Analyzer.
Enzymes
Eight tests for enzymes are available for use on the VetTest analyzer. Please read the
following information as well as the section on the individual chemistry tests.
The eight enzymes fall into one of two categories: those found in the cellular
cytoplasm (or mitochondria) and those bound to cell membranes.
Enzymes in cellular cytoplasm
Enzymes found in the cellular cytoplasm or mitochondria are: ALT (SGPT), AMYL, AST
(SGOT), CK, LDH, LIPA. Cells release these enzymes when there is a change in the
membrane permeability or when frank necrosis occurs. The amount of these enzymes
in the blood stream is therefore a function of the rate at which the enzyme is being
released from the cells, and the rate at which it is being cleared from circulation.
When only minor, transient changes occur in the morphology and function of cells,
these enzymes may be released quite easily. Therefore, they are often early indicators
of cellular damage.
Enzymes bound to cell membranes
Enzymes bound to cell membranes (not present in cellular fluid) are: ALKP, GGT.
These enzymes are commonly used to detect diseases of the hepatic or biliary system.
However, neither ALKP nor GGT are present in large amounts in any of the liver tissues
and they are not released when hepatic necrosis occurs. Their activity increases in the
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are released is not completely understood, but may be caused by de novo synthesis,
solubilization or a mechanism not yet identified. Increases in the serum activity of these
enzymes are associated with potentially serious lesions.
Enzymes as Indicators of Organ Damage
When the liver is damaged, liver enzymes are released into the circulation. In acute
damage through, for example, exposure to a toxicant such as carbon tetrachloride,
the lesion is transient and enzymes leak from the tissues during the period of active
cell damage. Afterward, repair processes begin and enzyme release declines and
eventually ceases. In this case there is a fairly narrow window of time, which is
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detected.
H–1

Idexx VetTest Specifications

General

Brand	Idexx
Model	VetTest
Category	Measuring Instruments
Language	English