clinical chemistry (wk 12)

Question 1

What must be combined with chemical analyses to help the veterinarian arrive at a final diagnosis?

Answer 1

Physical exam and history

Question 2

Describe how a spectrophotometer works

Answer 2

Designed to measure the amount of
light transmitted through a solution

Question 3

Describe Beer’s Law

Answer 3

A direct linear relationship exists between the concentration of an analyte and the light absorption when monochromatic light is passed through the sample. The transmission of the
monochromatic light through a sample and the concentration of an analyte
in the sample have an inverse exponential relationship.
*Degree of color change is proportional to the solution’s concentration

Question 4

Describe End point readings

Answer 4

The reaction that occurs between the sample and the reagent reaching a stable end. An internal standard curve is created when the instrument is calibrated

Question 5

When are kinetic methods used rather than end point?

Answer 5

• Do not reach a stable end point
• Measured at a specific time after initiation of the reaction
• Different for each analyte
• Several points are evaluated, and then patient results are calculated

Question 6

When must the chemistry machine be recalibrated?

Answer 6

When a new lot of reagent.

Question 7

Enzymes can be denatured by what three things?

Answer 7

Temperature, pH, or organic solvents

Question 8

What are the three units of measure for enzyme concentrations?

Answer 8

 Milliunits per milliliter (mU/mL)
 Units per liter (U/L)
 Units per milliliter (U/mL)

Question 9

How are enzymes named? Give an example

Answer 9

Enzymes are named for the substrate on which they act or the biochemical reaction in which they participate; Lipase-lipids

Question 10

Describe the electrochemical method

Answer 10

Incorporates electrodes with biosensor
reagent strips or cartridges

Question 11

Which is the least expensive liquid or dry reagents and why?

Answer 11

Liquid reagents:
Available in bulk, Least expensive but require storage and additional
handling, Some are flammable and toxic

Question 12

Why is it important for the chemistry analyzers to integrate with the practice
management software?

Answer 12

Enables results to be recorded into patient records Eliminates missed charges

Question 13

What is a control sample?

Answer 13

sample with known values used to test the machine’s accuracy

Question 14

What is a negative control? What result should you get if the machine is working correctly?

Answer 14

substance that should produce a negative test or zero values when run

Question 15

What is a positive control? What result should you get if the machine is working correctly?

Answer 15

commercially prepared; Comes with results sheet

Question 16

What is an “unknown”?

Answer 16

sample with unknown values (from the animal)

Question 17

What does “calibration” mean? List at least 2 different circumstances when the machine needs to be re-calibrated.

Answer 17

• adjusting the machine so that it
  compensates for things that would cause results to be inaccurate
• Some machines calibrate automatically when performing tests
• Most machines need periodic re-calibration by the operator. Re calibration is usually required if inaccurate results are produced when running a control, or when the machine is installed or moved

Question 18

qualitative

Answer 18

yes or no; no specific values or numbers; heartworm

Question 19

quantitative

Answer 19

specific values; PCV or TP

Question 20

quality control

Answer 20

testing for accurate results; the beads

Question 21

control

Answer 21

known

Question 22

negative control

Answer 22

known to have negative values

Question 23

internal control

Answer 23

positive, negative, or both; run with unknown and flags what could be false