Anemia & RBC Disorders Flashcards
What is the complete blood count (CBC)?
- a basic screening test and is one of the most frequently ordered laboratory procedures
- gives valuable diagnostic information about the hematologic and other body systems, prognosis, response to treatment, and recovery
The CBC consists of a series of blood cell tests that determine their: (5)
- number
- variety
- percentage
- concentrations
- quality
The 3 main components of the CBC
- Red Blood Cell Count and Indices
- White Blood Cell Count and Differential
- Platelet Coun
“normal” values for a CBC can be affected by several factors including the patient’s: (3)
- age
- sex
- race
Red blood cells (RBCs) (also called erythrocytes) are the largest cellular component of blood comprising about:
- 40 - 45% of total blood volume, and
- 99.9% of formed blood elements.
RBCs contains the red, iron-based protein _______ which binds and transports O2 and CO2
hemoglobin
Hemoglobin contains
- 4 molecules of heme:
- Each molecule of heme contains one iron (Fe2+) ion - 4 molecules of globin:
- 2 alpha chains, and 2 beta chains
What is the size of each RBC
a biconcave disc:
* Diameter: 6.2 - 8.2 µm
* Thickness: 2.0 - 2.5 µm
Why are RBC’s a biconcave disc?
- It provides an increased surface area for O2 and CO2 transfer.
- It enables them to bend and flex when entering small capillaries
Mature RBCs lack a ______ and most cellular organelles.
RBCs normally survive about _____ days in the blood before they are removed primarily by the _______
- nucleus
- 120
- spleen
a reduction in hemoglobin concentration and/or red blood cell mass
anemia
What is the RBC count?
The total number RBCs per unit volume of whole blood.
What physiologic variants effect RBC count?
- exercise
- age
- altitude
- pregnancy
- many drugs
What is RBC count increased in?
- Secondary polycythemia (e.g. secondary to cardiovascular disease, COPD)
- hemoconcentration (dehydration)
- polycythemia vera
- etc
What is RBC count decreased in?
Anemia, chronic or acute blood loss, fluid overload, bone marrow suppression/disease, etc.
What is hematocrit (HCT)?
the volume percentage (%) of red blood cells in whole blood
How is hematocrit calculated
- usually by placing a hematocrit tube in a centrifuge
- or by multiplying the RBC count by the mean corpuscular (cell) volume (MCV)
What physiologic variants effect outcomes of hematocrit?
Age, pregnancy, many drugs
Hematocrit may be increased in:
Any condition that increases RBCs including hemoconcentration (as in dehydration, severe burns, vomiting, diarrhea), polycythemia (erythrocytosis), extreme physical exercise, etc.
Hematocrit may be decreased in:
Many conditions that decrease RBCs including anemia, hemodilution, acute hemorrhage, bone marrow suppression/disease, etc.
what is hemoglobin, total, whole blood (Hgb or Hb):
the amount of hemoglobin in a given volume of whole blood.
Physiologic variants that effect hemoglobin?
Age, high altitude, excessive fluid intake, pregnancy, and many drugs.
Hemoglobin may be increased in:
Hemoconcentration (as in dehydration, severe burns, vomiting), polycythemia (erythrocytosis), extreme physical exercise, hyperlipidemia, etc
Hemoglobin may be decreased in:
Anemia, acute hemorrhage, hemodilution, bone marrow disease/suppression, etc
A hematocrit of < 20% can lead to ________.
A hematocrit > 60% is associated with ________.
- heart failure and death.
- spontaneous clotting of blood.
A hemoglobin value < 5.0 g/dL leads to _________
A hemoglobin value > 20.0 g/dL results in __________
heart failure and death.
hemoconcentration and clogging of capillaries
What is Mean corpuscular (cell) volume (MCV)? What is the normal range?
MCV is the average volume of the red blood cells
MCV may be increased in:
Liver disease, alcohol abuse, HIV/AIDS, hemochromatosis, megaloblastic anemias (folate, vitamin B12 deficiencies), myelodysplasia, reticulocytosis, chemotherapy, post-splenectomy, hypothyroidism, newborns, drugs (e.g., methotrexate, phenytoin, zidovudine), etc.
MCV may be decreased in:
Iron deficiency, thalassemia, sideroblastic anemia, lead poisoning, hereditary spherocytosis, some anemias of chronic disease, etc.
What is Mean Corpuscular (Cell) Hemoglobin (MCH)? What is a normal range?
- the average amount of hemoglobin per red blood cell (RBC) in absolute units
How is mean corpuscular hemoglobin (MCH) calculated?
- calculated from measured values of hemoglobin (Hgb) and RBC count by the formula: MCH = (Hgb ÷ RBC count) x 10
MCH may be increased in:
Macrocytosis, hemochromatosis, etc
MCH may be decreased in:
Microcytosis (iron deficiency, thalassemia), hypochromia (lead poisoning, sideroblastic anemias, anemia of chronic disease), etc.
While MCV can indicate if RBCs have a normal ______, it cannot indicate if the RBCs have a normal ______
- mean volume
- shape
What are characteristics related to RBC color?
- hypochromia (paler than normal)
- hyperchromia (more red than normal)
- polychromia (variations)
What is Mean Corpuscular Hemoglobin Concentration (MCHC)? What is a normal range?
- the average hemoglobin concentration in RBCs.
How is mean corpuscular hemoglobin concentration (MCHC) calculated?
- calculated from hemoglobin concentration (Hgb) and the hematocrit (HCT) by the formula: MCHC = (Hgb ÷ HCT) x 100.
MCHC may be increased in:
Marked spherocytosis (hereditary spherocytosis) or immune hemolysis), etc. Falsely increased in cellular dehydration syndromes, hyperlipidemia, etc
MCHC may be decreased in:
Hypochromic anemias (iron deficiency, thalassemia, lead poisoning), sideroblastic anemia, anemia of chronic disease, etc. Falsely decreased with markedly high white blood cell count.
What is Red Cell Distribution Width (RDW)? What is a normal range?
- a measure of the variation of RBC volume.
How is red cell distribution width (RDW) calculated?
- calculated with the formula: RDW = (standard deviation of MCV ÷ mean MCV) × 100
What is anisocytosis?
An abnormally high (increased) RDW