1304- how to make a blood smear (4)

Why do we need our blood smears to be of quality?

for an accurate evaluation of cell morphology, type, numbers, etc

Can blood smears be used as a diagnostic tool for diseases?

YES, for hematological analysis

The counting area at the thin portion of a wedge smear should look how?

have ~200 RBCs not touching

5 signs of a good blood smear

Smooth gradient, thick to thin

Uniform edge at termination point

No streaks, ridges, waves, gaps, clumps, or throughs

Feathered edge for optimal cell examination

Occupies 2/3 of the slide

What could a unique ID be on a label? What are the choices?

PT name

barcode of spec

DOB

hosp #

spec #

How do you label a blood smear

2 unique IDs

Date spec was collected

Initial of tech making the smear

Burr cells are aka?

ECHINOCYTES

How do echinocytes occur?

The tech didnt let the smear dry enough

IF a field is half-full of echinocytes and it ISNT you fault, what should you do?

These are common in burn patients

Check the PTs urea for renal failure

Name a few common causes for a poor blood smear

Dirty slide

Too much pressure/slide bouncing

Blood didnt go far enough

Not enough blood, high HgB, went too fast

Came off slide at an angle

Clot in center (or fat spicule)

Delayed prep

Improper angle

High humidity

Dirty spreader slide

Drying artifact

Lipids in the blood lead to a blood smear with holes, what do you do about it?

NOT your fault, cant do anything

What issues do a thick blood smear lead to?

Counting area is too small + RBCs overlap

When looking at a blood smear, what are the requirements for the observing field?

You need at least ten fields where 50% of RBCs don't overlap

What happens if you use old blood for a smear?

Cellular distortion

What happens if you delay prepping a blood smear?

large cells are located near feather edge

What happens if you use dirty slides for a smear?

leads to uneven prep of blood film

How does the pusher slides angle affect a blood smear?

thick if angle increased

thin if decreased

What does high humidity do to blood smears?

prolonged drying and distorts RBCs

What does drying artifact look like?

RBCs look mangled/full of bites/holes

How does drying artifact happen?

occurs when you don't allow the slide to dry properly

If you slide too slow, what happens to the smear?

produces irregularities

What happens if you use a rough/dirty spreader?

gives gritty feathered edge and excessive tails

Name a few causes of thin blood smears

Too small of a drop

Too slow to spread

Too low an angle

Looking at a smear, how can you tell if you used too low of an angle?

RBCs look like spherocytes + there's increased WBCs (neutro/mono) in tail

Name a few limitations to making blood smears:

1) has to be done as soon as blood touches slide

2) need clean glass slides

3) angle of spreader slide depends on RBC drop size and viscosity

4) hematocrit affects angle

5) automated diffs are specific enough

What happens if you let your blood drop sit on the slide too long?

the blood will clump and dry, resulting in uneven distribution of white blood cells and platelets

What is the optimal angle for blood smear preps?

30-45 degrees

Large drop of blood + small hematocrit =

greater the necessary angle needs to be to ensure that the blood smear is not too long

Large hematocrit =

requires a smaller angle to avoid a smear that is not too short and thick

Explain one downside to automated differentials

they dont meet specified criteria programmed into the automated hema instrument→ the tech must perform a manual diff count from a smear