Hematology Basics

Question 1

Sample Processing

Blood type, tube, issues

Answer 1

Whole blood
Purple EDTA
Clotted, contaminated, lipemic, icteric, hemolyzed, mislabeled, wrong tube

Question 2

CBC Procedure

Answer 2

Check for validation
Check for clotting/issues
Call criticals (don’t want to wait for diff if critical)
Check diff
Send to path or report

Question 3

Blood Smear

Areas and uses, blood thickness

Answer 3

Feathered edge: platelet clumping, cannot use for leukocytes or RBCs
Monolayer: for WBCs and red cells

Thick blood: push slower, decreased angle
Thin blood: push faster, increased angle

Question 4

WBC Estimates

10x, 40x calculations, pros and cons

Answer 4

10x: avg 5-6 fields / 5
Faster, cannot differentiate easily

40x: avg 10 fields x 2
Differentiate easier, slower

Question 5

Platelet Estimates

Procedure, calculation, reference range, clumping

Answer 5

Always on 100x
Avg 5 fields x 15
150 - 400 x 10^3 / uL
Clumping can falsely decrease count

Question 6

NRBCs

Minimum, calculation

Answer 6

Correct for NRBC if >10

(WBC x 100) / (100 + # NRBCs)

Question 7

H/H

Function and units

Answer 7

Hemoglobin: carry oxygen and CO2, buffers blood, g/dL
Hematocrit: packed RBC volume, %

Question 8

HemoCue

Procedure

Answer 8

Measures HGB by lysing RBCs and mixing with reagents, will self test in a microcuvette

Question 9

Rule of 3

Answer 9

RBC x 3 = HGB
HGB x 3 = HCT within 3%

Works best with normal morphology

Question 10

WBC Reference Range

Answer 10

3.6 - 10.6 x 10^3/uL

Question 11

RBC Reference Range

Answer 11

4 - 6 x 10^6/uL

Question 12

HGB Reference Range

Answer 12

12 - 18 g/dL

Question 12

HCT Reference Range

Answer 12

35 - 50%

Question 13

MCV

Reference range, calculation

Mean cell volume, micro/macrocytic

Answer 13

76(80) - 100 fL
(%HCT x 10) / RBC

Question 14

MCH

Reference range, calculation

Mean cell hemoglobin, hyper/hypochromic

Answer 14

26 - 34 pg
(HGB x 10) / RBC

Question 15

MCHC

Range, calculation

Answer 15

32 - 36 g/dL
HGB / HCT as a decimal

Question 16

Absolute WBC Calculation

Answer 16

Specific cell count as decimal x total WBC count

Question 17

Relative WBC Ranges

segs, bands, lymphs, monos, eos, basos

Answer 17

Segmented neutrophils: 40-80
Bands: 0-5
Lymphs: 25-35
Monocytes: 2-10
Eosinophils: 0-5
Basophils: 0-1

Question 18

Erythrocyte Sedimentation Rate (ESR)

What is it, ref range, methods

Answer 18

Non specific test for inflammation, rate that blood falls
0-20 mm/hour
Wintrobe tube or automated

Question 19

ESR Effects

Cells and technical factors

Answer 19

Red Cell Factors:
Fall faster: large cells, anemia
Fall slower: polycythemia, poikilocytosis

Technical factors
Fall faster: tilted tube, higher temperature
Fall slower: lower temperature, old samples