Normal CBC Values

Question 1

Give the normal values for the following CBC lab tests:
RBCs
Hgb
Hct
MCV
MCH
RDW
Platelets

Answer 1

RBCs: ~ 4 - 5.5
Hgb: ~ 12 - 17
Hct: ~ 37 - 51
MCV: 80 - 96
MCH: ~ 23 - 28
RDW: < 15%
Platelets: 150,000 - 400,000

Question 2

Give the normal values for the following CBC lab tests:
WBCs
Neutrophils (aka polys, segs)
Lymphs
Monos
Eosinophils
Basophils

Answer 2

WBCs: ~ 4 - 15

The sum of the following should ALWAYS = 100%:

Neutrophils: ~ 55 - 75%
Lymphs: ~ 20 - 40%
Monos: ~ 0 - 12%
Eosinophils: ~ 0 - 6%
Basophils: ~ 0 - 6%

Question 3

What is the definition of RDWs? What is their significance?

Answer 3

RDW: Red cell Distribution Width

Definition:
- the degree of variation in size of RBCs

Significance:
- elevated RDW usually corresponds to anemia of recent onset (~ 4 - 6 months)
- level normalizes when most RBCs are small at >/= 120 days

Question 4

Give the definition, normal value, and significance of reticulate count?

Answer 4

Definition:
- immature RBCs that mature in ~ 3 days

Normal value: ~ < 1%

Significance:
- will elevate initially with anemia
- if no elevation with anemia, suspect bone marrow problem

Question 5

What are the roles of polys, lymphs, and monos in infection?

Answer 5

Polys and lymphs are 1st responders = within 2 hours

Monos are 2nd responders = within 24 hours

Question 6

How do poly and lymph values indicate bacterial versus viral infection?

Answer 6

High polys & low lymphs = bacterial
Low polys & high lymphs = viral

Tip:
B = L < P
L > P = V

Question 7

What are the roles of eosinophils and basophils?

Answer 7

Eosinophils:
- trigger inflammatory response
- fights parasites
- mediates allergic reactions

Basophils:
- contains heparin (to prevent quick clotting)
- contains histamine
- induces inflammatory response

Question 8

What is the definition and significance of bands? Blasts?

Answer 8

Bands: immature WBCs

Blasts: VERY immature WBCs
- should NEVER be in circulation

High WBCs and blasts indicate a bone marrow problem