Flashcards in L27: Complete Blood Count (CBC) Deck (44)
What are the major components of a CBC?
Red blood cell count (RBC)
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)
How is WBC, RBC, and PLT measured?
Number of cells per unit volume (µL or L)
What is HGB?
The concentration of hemoglobin in the RBCs (g/dL)
What is HCT?
% of packed RBCs per packed volume of whole blood
What is the rule of three?
When RBCs are normal
HGB x 3 = HCT +/- 3
What is the reference range for WBCs?
Male and female: 4.5 - 11.5 x 10^3/µL
What is the reference range for HGB?
Male: 13.5 - 18.0 g/dL
Female: 12.0 - 15.0 g/dL
What is the reference range for HCT?
Male: 40 - 54%
Female: 35 - 49%
What is the reference range for RETIC?
What is the reference range for PLT?
Male and female: 150 - 450 x 10^3/µL
What is commonly called H & H?
HGB and HCT
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
What does decreased HGB, HCT, RBC count indicate?
Decreased production, increased destruction (hemolysis), blood loss, dilutional (increased plasma volume)
What does increased HGB, HCT, RBC count indicate?
Benign and malignant causes, severe hydration (decreased plasma volume)
What is MCV?
Average volume of RBCs (fL)
What is MCHC?
Hemoglobin concentration in a cell
Average weight of hemoglobin per RBC in pg
Correlates w/ MCV
<30 g/dL is hypochromic
What is the most important RBC indice?
What are RBCs with a normal MCV called? How do they appear on blood film?
RBC diameter is normal
Central pallor 1/3 of cell
What are RBCs w/ increased MCV called? How do they appear on blood film?
What are the causes?
RBC diameter is increased
Found in megaloblastic anemia, myelodysplastic syndrome, bone marrow failure, liver disease
What are RBCs w/ decreased MCV called? How do they appear on blood film?What are the causes?
MCV, MCHC decreased
RBC diameter is decreased
Central pallor > 1/3 of cell
What is RDW?
Red cell distribution width
Measures variation in red cell volume
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
Why is it important to look at MCV and RDW together?
MCV can be the same but distribution can indicate abnormalities
What is increased RWD called?
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
What are retics?
Last immature RBC stage
What is the clinical sue or retics?
Estimate of erythropoietic activity of BM in anemia (or BM's ability to replace RBCs)
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
What does decreased retic count indicate?
Bone marrow NOT responding to anemia
Bone marrow failure
What does interpreation of WBC count depend on?
Type of cell affected
What is increased WBC count called? What does it indicate?
Infections, inflammation, some leukemias
What is decreased WBC count called? What does it indicate?
Some hematologic malignancies, bone marrow failure, megaloblastic anemia
What is WBC differential count?
Proportion of each type of WBC
Absolute (# per µL or L)
Is relative or absolute WBC count more reliable?
How is absolute count measured?
Absolute count = Total WBC count x % cell
How is absolute neutrophil count (ANC) measured?
ANC = Total WBC x (% Neut + % Bands)
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
What is left shift?
Shift to the left, band shift
Increase in bands and presence of immature neutrophils in PB
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
What are NRBCs?
When are NRBCs normally present?
Present in PB of neonates in small #s
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)
What is increased PLT count called? What does it indicate?
Various benign and malignant causes