Clinical Pathology
K. Canga, RVT

• Read pp: 32 – 38 (Start at CBC, end before histograms)
• You MUST register at IDEXXLearningCenter.com and complete the course titled: “The VetTest
Certificate Course” RACE #106-11660
• This is FREE, and will count as 3 hours of CE to use after you become licensed.
• The course will take ~ 3 hours and you need to turn in a certificate of completion prior to using the IDEXX machines at school.
• Certificates are due by Monday, May 5. PLEASE print a hard copy. No Engrade or e-mail message will be accepted. (Yes, this is for points)

• Total RBC count
• PCV
• Plasma Protein Concentration
• Total WBC count
• Blood film evaluation (differential WBC count,
RBC and WBC morphological evaluation, platelet estimation)
• Reticulocyte count
• Hb Concentration
• Erythrocyte indices (They’re baaack) 

• Should be in the millions
• Usually done by machine
• Can be done manually with
– Unopette and Hemacytometer
– Is outdated and difficult to obtain diluents

• Packed Cell Volume
• Indicates the percent of packed red cells in a patient’s blood.
• Done with hematocrit tube that has been centrifuged
• Takes VERY little time and can be quick diagnostic tool
• Normal ranges?

• Utilize the already centrifuged PCV tube
• Read using a refractometer
• Helps to determine abnormal amounts of protein in blood
– Protein present may be from fat, or other sources.
– Normal Ranges?

• Usually done by machine
• Can be done manually with unopette and hemacytometer method. (Again, outdated and difficult to obtain diluents)
• Critical in determining absolute number of
WBCs. This is the number with diagnostic value.

• Used to calculate the relative WBC percentages
• Used to evaluate RBC and WBC morphologies
• Used to perform reticulocyte count if patient is anemic
• Used to Perform platelet estimation.
– REVIEW retic. and platelet calculations. I am not going to re-teach these.

• You must have done a relative percentage from a blood film. (Written as a %)
• You must have a total WBC count
• You will then take each relative percentage and multiply each by the total WBC count from your CBC analyzed blood.

• Your relative percentages were as follows:
– Neutrophils: 52%
– Lymphocytes: 38%
– Monocytes: 7%
– Eosinophils: 3%
– Basophils: 0%
• Take each cell’s percentage and multiply by the total WBC numbers from the machine readout. Let’s say that your total was 38,000.

• 38,000 x 52% = 19,760 total neutrophils
• 38,000 x 38% = 14,440 total lymphocytes
• 38,000 x 7% = 2,660 total monocytes
• 38,000 x 3% = 1,140 total eosinophils
• 38,000 x 0% = 0 total basophils
• The % is VERY important in your calculation.
Simply hit the % key after you punch in the number you are multiplying the total by.
• NOTICE that your numbers add up to 38,000!

• Usually done by machine
• Different machines use different techniques to estimate Hb concentration
– Lysing solutions
– Photometrics
– Are only as accurate as machine is. Calibration is important.

• MCV: Average volume within RBC
• MCHC: Average Hb concentration within RBC
• MCH: Average weight of Hb within RBC
– Review these calculations please!

• Blood MUST be drawn in both Lithium-Heparin micro tube AND large purple top tube. (These are tubes designed for the IDEXX machines)
• You can use a serum separator tube in place of the lithium heparin tube.
• REMEMBER:
– DO NOT remove the stopper from the large purple top tube.
– DO NOT fill tube past bottom of label (0.5 – 1.5 cc)
– You WILL need to remove the top from the microtube.

• Centrifuge the microtube or serum separator tube for ~7 minutes.
• Transfer plasma or serum off and place in serum cup. (Barbie shot glass)
• Place purple top tube and grey top tube obtained from Ms. Kenner in CBC machine.
• Bar codes on purple and grey tubes MUST
MATCH in order for your tests to be valid. (If purple tubes do not have a bar code, this is
OK, as long as they’re the large tubes!)

• To run the chemistry portion of the test, you will obtain test slides from Ms. Kenner
• On the Monitor of the VetLab Station, use the stylet to enter the following information:
– Click “Analyze Sample”
– Enter Client: “VTI”
– Enter P. Name: Patient id # is fine
– Select next and then select reason: “Routine
SX/Wellness”
– At the bottom of the screen, you will need to tap the test icons desired. (CBC and Chemistry) and THEN
– STOP

• If you haven’t already loaded the large purple top and grey top tubes in to the CBC machine, do so now. Then hit RUN
• Look at the LED screen on the body of the Vet
Test Machine.
• Follow prompts on the LED screen.
– This is where you will add the slides ONE AT A TIME.
(DO NOT OPEN the foil until you are ready to load the slide in to the machine.)
– DO NOT touch the center of the slides. You will need to handle the slides by the edges and make sure the bar code is UP

• Once you have placed all the slides in the machine, follow the prompts on the LED screen.
• Place pipette tip securely on the pipettor of machine.
• Press “E” on LED keyboard to continue the analysis.
• lower pipette into plasma and press button.
Machine will beep 1 time. (Release button)
• 2 beeps: Remove pipette
• 3 beeps: wipe pipette tip and replace in machine within 20 seconds. You will hear one more beep after pipette is replaced.

• The machine will automatically pipette the appropriate amount of plasma on each slide to run the tests.
• Total run time is ~6 minutes
• When test is complete, press E
• Remove pipette tip, empty used slide drawer
• Machine should start printing results. If not, press E and wait. If results are still not printing, try selecting option 2: print results.

• The internal printer on the IDEXX machine is disabled on our machine.
• We have an external printer connected to print results.
• PAPER MUST BE LOADED before you start running tests.