CBC Flashcards
Components of CBC
- WBCs
- RBCs
- Hgb
- Hct
- Mean Cell Volume = MCV
- Mean Cell Hgb = MCH
- Mean Cell Hgb Concentration = MCHC
- Platelet count = Plt ct
- Differential (% & absolute # of each type of WBC)
WBC abnormalities
- Infection
- Inflammation
- Neoplasm/malignancy
- Drug rxns
Hgb/ hct abnormalities
- Anemia
- Polycythemia
Platelet abnormalities
- Bleeding disorders
- Hyper-coagulable
WBC count
Total # of WBCs
Differential
% of each type of leukocyte present in sample
What population tends to have higher WBC counts?
Newborns
Granulocytes
- Granules in cytoplasm & multi lobed nucleus
- Aka. PMNs or “polys”
Neutrophils
- Most common
- Phagocytosis of bacteria
Eosinophils
Allergic rxns
Basophils
- Aka. Mast cells
- Allergic rxns
Nongranulocytes
- Lymphocytes (T & B cells)
- Monocytes
What do lymphocytes do?
Fight acute viral infections & chronic bacterial infections
What do monocytes do?
Phagocytic cells capable of fighting bacteria (like neutrophils do)
Leukocytosis characteristics
> 10,000
- Bacterial infection*
- Inflammation
- Neoplasm
- Leukemoid response
- Glucocorticosteroid use
Leukopenia
< 5000
- Viral or bacterial infection
- Bone marrow failure
- Drug toxicity
- Autoimmune disease
Define: leukocytosis
Increase of total WBC count w/ a left shift
The “left shift”
- Elevated WBC count due to an increase in neutrophils & bands (baby neutrophils)
- Bands enter circulation when neutrophil production is highly stimulated (ex. acute bacterial infection)
Leukemoid response
- Development of early neutrophilic cells
- Elevated WBC > 50,000
- Associated w/ infection
- Benign, typically resolves as primary condition resolves
Neutrophilia
- Elevated neutrophil count
- Leukemia
- Inflammation
- Medications
- Stress
Neutropenia
- Decreased neutrophil count
- Viral infection
- Aplastic anemia
- Bacterial infection (esp. in elderly, as they may not be able to generate response)
- Drugs
Lymphocytosis
Elevated lymphocyte count
- Viral infections (Mononucleosis, hepatitis)
- Lymphocytic leukemia
Lymphocytopenia
Decreased lymphocyte count
- Corticosteroids*
- Immunodeficiency diseases* (late stage HIV)
- Leukemia
- Radiation therapy
- Sepsis
Eosinophilia
Elevated eosinophil count "NAACP": - Neoplasm (includes leukemia)* - Allergic rxns - Addison’s disease - Collagen vascular disease (autoimmune diseases) - Parasites *And in the Valley, Coccidiomycosis (“NAACCP”)
Eosinopenia
Decreased eosinophil count
- Corticosteroids (the opposite of Addison’s disease)*
- Acute stress or inflammatory conditions
What is a common/useful parameter of infection?
Total neutrophil count
What is used for dx & px?
Serial WBC & differential counts
Acute leukemia
Bone marrow shows a predominance of the most immature elements (myeloblasts)
Platelet count RR
150,000-400,000
Platelet fxn
- Initiates coagulation cascade
- Hemostasis
Critical platelet count
<50,000 or > 1 million
What could happen if platelet count <20,000?
Spontaneous bleeding
Thrombocytosis
Increased platelet count (>400,000)
- Malignancy*
- Polycythemia vera
- Postsplenectomy syndrome
- Drugs (estrogens, oral contraceptives)
Thrombocytopenia
Decreased platelet counts (<100,000)
- ITP
- TTP
What is thrombocytopenia associated w/ ?
- Leukemia
- Cirrhosis
- DIC (disseminated intravascular coagulation)
- Anemia (hemolytic, pernicious)
ITP is most common in …
Children
- Also common in AIDS
ITP etiology
Autoimmune:
- Develops antibodies against own platelets
- Massive phagocytosis of platelet-antibody immune complexes occurs in the spleen
ITP hx
- Usually asymptomatic except for mucosal & skin bleeding due to decreased platelets
- Antecedent viral infection
ITP PE
- Petechiae
- Purpura
- Epistaxis
- Menorrhagia
ITP lab findings
- Platelet count low < 10,000
- Other blood counts & peripheral smear normal
ITP tx/px
- Self-limited in children
- In adults – corticosteroids
- If unresponsive to medical therapy, possible splenectomy
What % of people will develop chronic ITP?
50-60%
RBC count RR
Male 4.7-6.1 x 10^6
Female 4.2-5.4 x 10^6
Define: RBC count
of circulating RBCs in peripheral venous blood
What do RBCs contain?
Hemoglobin
What is the lifespan of RBCs?
120 days
- After this time, RBCs extracted by spleen
Hemoglobin RR
Male 14-18
Female 12-16
Define: hemoglobin
Total amount of hemoglobin in the blood
Hgb fxn
Binds & transports O2
Hct count RR
Male 42-52%
Female 37-47%
Define: Hct
% of the total blood volume that is made up by RBC’s
Hct vs Hgb
Hct is 3 times that of the Hgb concentration
Increased RBCs - associated w/ what?
- Dehydration
- COPD
- Polycythemia vera
Decreased RBCs - associated w/ what?
Anemia
- Bleeding / Fe deficiency
- B12, Folate deficiency
- Cirrhosis
- Bone marrow failure
- Pregnancy
Polycythemia/ erythocytosis (increased RBCs, Hct, Hgb) - associated w/ what?
- Dehydration
- Polycythemia vera
- Smoking & COPD
- High altitude
Categories of polycythemia
- Relative:
- Due to decreased plasma volume (dehydration) –> Elevated hct w/ normal RBC - Absolute:
- Polycythemia vera (bone marrow disorder) –> elevated hct w/ increased RBC
- Secondary polycythemia: increased erythropoietin production. Tissue hypoxia = major cause
Polycythemia vera etiology
Overproduction of erythroid cells
Polycythemia hx
- HA, dizziness, tinnitus, blurred vision
- Fatigue
- Pruritus following warm shower or bath
Polycythemia PE
- Engorged retinal veins
- Thrombosis
- Splenomegaly
Polycythemia lab findings
- Elevated Hgb/Hct
- Increased RBC*
- Leukocytosis
- Thrombocytosis
Polycythemia tx
Phlebotomy
Causes of anemia (3)
- Reduced production of RBCs
- B12, folate, iron deficiencies, bone marrow failure
- Renal failure (↓erythropoietin) - Increased destruction of RBCs
- Hemolysis
- Hemoglobinopathies, drugs - Loss of RBCs
- Bleeding
MCV
Average RBC size
- Microcytic, normocytic, macrocytic
MCH
Weight of Hgb in RBC
MCHC
Hgb concentration
- Hypochromic, normochromic, hyperchromic
RDW
Variation in RBC size
- Degree of anisocytosis
Categories of microcytic anemia (Decreased MCV, small RBCs)
- Iron deficiency
- Lead poisoning
- Thalassemia
Iron deficiency
- Microcytic hypochromic
(↓ MCV & ↓MCHC) - Usually due to chronic blood loss: GI bleed, menstrual blood loss
What does lead poisoning cause?
Mild microcytic hypochromic anemia w/ basophilic stippling on peripheral smear
Thalassemia
Hereditary, reduced synthesis of globin chains
- Associated w/ patterns of bands
Thalassemia minor
- RBCs will be small (↓ MCV), but total RBC count may be normal or elevated
- Peripheral smear may reveal target cells & basophilic stippling
Thalassemia dx & components of this test
Hemoglobin Electrophoresis:
- Detects abnormal forms of Hgb
- Also used to dx sickle cell anemia
- Different Hgb variations (eg. A1, A2, F, S)
- Hgb from lysed RBCs placed on electrophoresis paper in an electromagnetic field - Hgb variants migrate at different rates & a pattern of bands is created
Normocytic anemia (normal MCV / normal-sized RBCs)
- Anemia of chronic disease (autoimmune diseases, malignancy)
- Renal failure
- Acute blood loss
Macrocytic anemia (↑MCV / big RBCs)
- Vitamin B12 & folate deficiency
* Alcohol consumption can cause a macrocytosis w/ or w/out anemia
Risk associated w/ anemia
Cardiac events
What should you consider if Hgb < 8, Hct < 24%?
Transfusion
Iron studies
- Iron level (serum iron): quantity of iron bound to transferrin
- TIBC (Total Iron Binding Capacity)
- Transferrin saturation
- Ferritin
- Ordered separately or grouped
What % of iron is found in hemoglobin?
70
Where is the other 30% of iron stored?
Ferritin & hemosiderin
Hemochromatosis
- Excess iron deposited in organs –> organ dysfunction
- Elevated LFTs
Types of hemochromatosis
- Primary: Genetic
- Secondary: Caused by repeated transfusions
TIBC
- Measures proteins available for binding mobile iron
- Measures transferrin
In what % of pts w/ iron deficiency is TIBC elevated?
70
Transferrin
- Main binding protein
- Negative acute-phase reactant protein
How is % of transferrin sat calculated?
(Serum iron level x 100%) / TIBC
What % of transferrin sat is seen in iron deficiency anemia?
< 15%
When would you see increased transferrin sat?
- Hemolytic, megaloblastic, sideroblastic anemia
- Hemochromatosis, other iron overload disorders
Ferritin
- Marker of iron storage
- Most sensitive test to detect iron deficiency
↓ ferritin = decrease iron storage = iron deficiency
↑ ferritin = iron excess (e.g. hemochromatosis)
