05: PCV/TP/UA

Proper technique to prepare a PCV tube

• Invert the blood tube to resuspend RBCs

• Tilt the blood tube sideways

• Place the PCV tube in at a slight angle to pull blood up via capillary action

• Stab the end into clay to seal the PCV tube

Proper way to place a PCV tube in a centrifuge

Place the prepared PCV tube into the centrifuge clay-side out, balancing the load and placing the lid on the microhematocrit centrifuge

How to read a PCV tube

Align the bottom of the RBCs with the bottom of the scale, roll the tube until the top of the serum aligns with 100, and read the line at the top of the RBCs

Non-numerical features to evaluate in a PCV tube

• Size of buffy coat

• Color of serum

How to measure TP from a PCV tube

Break the centrifuged PCV tube right above the buffy coat and place the serum on a refractometer

Feature of a well made blood smear

Smooth feathered edge

Reasons to run a UA very quickly

Urine changes quickly if it sits

Most common way to check USG

Refractometer

If you are dipping a urine dip stick, why shouldn’t you leave it in for longer than 1 second

You don’t want to cross contaminate your test pads

T/F: after incubating the dip stick with urine, you check all the test pads at 1 minute

F; all of them have slightly different times to be read

Test pads on a human urine dip stick that we can’t use for veterinary patients

• USG

• WBC

• Nitrates

If you can’t use the WBC dipstick test pad, how do we measure WBC

Urine sediment

Important handling note when spinning something down in a centrifuge

• BALANCE the darned thing

• Don’t forget the lid

Species that often incidentally has a lot of crystals in their sediment

Horses → calcium carbonate!

How to prep a slide for urine sediment analysis

• Decant most of the urine off

• Resuspend the sediment pellet in a couple drops of urine left in the tube

• Place a drop or two on a slide with a coverslip

  • OR: air dry and stain like a blood smear

Reasons to stain a sediment slide over doing a wet mount

You can differentiate junk from bacteria, WBCs, and urothelial cells if you stain the slide