L27: Complete Blood Count (CBC) Flashcards Preview

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Flashcards in L27: Complete Blood Count (CBC) Deck (44)
1

What are the major components of a CBC?

Red blood cell count (RBC)

Hemoglobin (HGB)

Hematocrit (HCT)

RBC indices - Mean cell volume (MCV)

Red cell distrubution width (RDW)

Reticulocyte count (RETIC)

White blood cell count (WBC)

WBC differential count (DIFF)

Platelet count (PLT)

2

How is WBC, RBC, and PLT measured?

Number of cells per unit volume (µL or L)

3

What is HGB?

Hemoglobin

The concentration of hemoglobin in the RBCs (g/dL)

4

What is HCT?

Hematocrit

% of packed RBCs per packed volume of whole blood

5

What is the rule of three?

When RBCs are normal

HGB x 3 = HCT +/- 3

6

What is the reference range for WBCs?

Male and female: 4.5 - 11.5 x 10^3/µL

7

What is the reference range for HGB?

Male: 13.5 - 18.0 g/dL

Female: 12.0 - 15.0 g/dL

8

What is the reference range for HCT?

Male: 40 - 54%

Female: 35 - 49%

9

What is the reference range for RETIC?

< 2.5%

10

What is the reference range for PLT?

Male and female: 150 - 450 x 10^3/µL

11

What is commonly called H & H?

HGB and HCT

12

What counts are higher in newborns and fetuses? Why?

Fetus and newborn have higher HGB, HCT, RETIC bc Hb F (the major hemoglobin in fetus) shifts the O2 dissociation to left resulting in hypoxia

13

What does decreased HGB, HCT, RBC count indicate?

Anemia

Decreased production, increased destruction (hemolysis), blood loss, dilutional (increased plasma volume)

14

What does increased HGB, HCT, RBC count indicate?

Polycythemia

Benign and malignant causes, severe hydration (decreased plasma volume)

15

What is MCV?

Average volume of RBCs (fL)

16

What is MCHC?

Hemoglobin concentration in a cell

Average weight of hemoglobin per RBC in pg

Correlates w/ MCV

<30 g/dL is hypochromic

17

What is the most important RBC indice?

MCV

18

What are RBCs with a normal MCV called? How do they appear on blood film?

Normocytic, normochromic

RBC diameter is normal

Central pallor 1/3 of cell

19

What are RBCs w/ increased MCV called? How do they appear on blood film?
What are the causes?

Macrocytic

RBC diameter is increased

Found in megaloblastic anemia, myelodysplastic syndrome, bone marrow failure, liver disease

20

What are RBCs w/ decreased MCV called? How do they appear on blood film?What are the causes?

Microcytic, hypochromic

MCV, MCHC decreased

RBC diameter is decreased

Central pallor > 1/3 of cell

21

What is RDW?

Red cell distribution width

Measures variation in red cell volume

22

What does increased RDW correlate with?

Anisocytosis (variation in RBC diameter on a blood smear)

Seen in: Deficiency of iron, vitamin B12, and/or foltate

Hemolytic anemias

23

Why is it important to look at MCV and RDW together?

MCV can be the same but distribution can indicate abnormalities

24

What is increased RWD called?

Anisocytosis

25

How might a bimodal histogram of RDW and RBC occur?

If you have a pt with microcytic anemia and you give them iron and they start producing normal cells

26

What are retics?

Last immature RBC stage

27

What is the clinical sue or retics?

Estimate of erythropoietic activity of BM in anemia (or BM's ability to replace RBCs)

28

What does increased retic count indicate?

Bone marrow responding to anemia

Hemolytic anemias, acute hemorrhage, after successful therapy for iron, vitamin B12, or folate deficiency

29

What does decreased retic count indicate?

Bone marrow NOT responding to anemia

Bone marrow failure

30

What does interpreation of WBC count depend on?

Type of cell affected

31

What is increased WBC count called? What does it indicate?

Leukocytosis

Infections, inflammation, some leukemias

32

What is decreased WBC count called? What does it indicate?

Leukopenia

Some hematologic malignancies, bone marrow failure, megaloblastic anemia

33

What is WBC differential count?

Proportion of each type of WBC

Relative (%)
Absolute (# per µL or L)

34

Is relative or absolute WBC count more reliable?

Absolute

35

How is absolute count measured?

Absolute count = Total WBC count x % cell

36

How is absolute neutrophil count (ANC) measured?

ANC = Total WBC x (% Neut + % Bands)

37

What occurs if instrument differential is abnormal?

Slide is viewed under microscope or w/ digital technology

Slide review includes morphology assessment of RBCs, WBCs, PLTs (including inclusions); looking for abnormal or immature blood cells or other abnormal findings

38

What is left shift?

Shift to the left, band shift

Increase in bands and presence of immature neutrophils in PB

39

What is the clinical correlation of left shift?

Bacterial infections usually present with neutrophilia and a left shift

Immature neutrophils also found in PB in myeloid malignancies

40

What are NRBCs?

Nucleated RBCs

41

When are NRBCs normally present?

Present in PB of neonates in small #s

42

What does presence of NRBCs in PB after 4 days of life indicate?

Indicates BM response to severe anemia or disruption of BM (leukemias, other malignancies)

43

What is increased PLT count called? What does it indicate?

Thrombocytosis

Various benign and malignant causes

44

What is decreased PLT count called? What does it indicate?

Thrombocytopenia

Excessive loss, consumption, or destruction

Decreased production in bone marrow

Maldistribution