Complete Blood Count - Red Blood Cell Indices and Platelet/Thrombocyte Count

Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red blood cell distribution width (RDW)

What are the RBC indices?

CBC; anemia

The RBC indices are ordered as part of a ______________ and are helpful in classifying ____________

Macrocytic, microcytic, normocytic, hypochromic, hyperchromic, and normochromic

What types of anemia are the RBC indices helpful in classifying?

Average volume (size) of a single RBC

What does mean corpuscular volume (MCV) measure?

microcytic, macrocytic, or normocytic

MCV is useful in determining if RBCs are...

Microcytic

Small RBCs

Normocytic

Normal sized RBCs

Macrocytic

Large RBCs

Average amount of Hgb per RBC

What does mean corpuscular hemoglobin (MCH) measure?

macrocytic, microcytic, and hypochromic anemias

MCH is helpful in classifying...

Macrocytic anemias; larger RBCs carry more hemoglobin

In what anemia(s) is/are MCH levels high? Why?

Microcytic and hypochromic anemias

In what anemia(s) is/are MCH levels low?

Average concentration (%) of Hgb per blood cell

What does mean corpuscular hemoglobin concentration (MCHC) measure?

Hypochromic, normochromic, and hyperchromic anemias because hemoglobin gives RBCs their color, so RBCs with lower concentrations will appear paler

What anemia(s) is/are MCHC helpful in classifying? Why?

hypochromic anemia; pale

A decreased MCHC is evident of a _________________ and RBCs will be ___________ in color

normochromic anemia; normal

A normal MCHC is evident of a __________________ and RBCs will be _____________ in color

hyperchromic; darker

A high MCHC is evident of a ______________ and RBCs will be _______________ in color

Variation in RBC width

What does red blood cell distribution width (RDW) measure?

They are widened, or have more variability in size

If RDW is increased, how are RBCs described?

80-95 fL (femtoliter)

What is a normal MCV?

27-31 pg

What is a normal MCH?

32-36 g/dL

What is a normal MCHC?

11%-14.5%

What is a normal RDW?

Microcytic hyperchromic

If an individual has a decreased MCV and MCH and a high MCHC, what kind of anemia would that be classified as?

Microcytic normochromic

If an individual has a decreased MCV and MCH and a normal MCHC, what kind of anemia would that be classified as?

Microcytic hypochromic

If an individual has a decreased MCV and MCH and a low MCHC, what kind of anemia would that be classified as?

Normocytic hyperchromic

If an individual has a normal MCV and a high MCHC, what kind of anemia would that be classified as?

Normocytic hypochromic

If an individual has a normal MCV and a low MCHC, what kind of anemia would that be classified as?

Normocytic normochromic

If an individual has a normal MCV and MCHC, what kind of anemia would that be classified as?

Macrocytic hyperchromic

If an individual has a high MCV and MCH and a high MCHC, what kind of anemia would that be classified as?

Macrocytic normochromic

If an individual has a high MCV and MCH and a normal MCHC, what kind of anemia would that be classified as?

Person has 250,000 platelets per cubic milliliter of blood

What does a platelet count of 250 mean?

small round nonnucleated; megakaryocytes; vascular integrity

Platelets are _________________________ cells that are formed from ____________________ to maintain ________________

blood clotting

Platelets are essential for...

True

T/F? Excessively high and low platelet counts are dangerous

Thrombocytopenia

Term used for when platelet counts are too low

<100,000/cubic mm

What platelet count indicates thrombocytopenia?

Spontaneous hemorrhage

What occurs due to thrombocytopenia?

Thrombocytosis

Term used for when platelet counts are too high?

>400,000/cubic mm

What platelet count is indicative of thrombocytosis?

Vascular thrombosis and sometimes organ infarction

What occurs with thrombocytosis?

increases

High altitude increases/decreases normal platelet counts

increases

Strenuous exercise increases/decreases normal platelet counts

decrease; estrogen and progesterone

Prior to menstruation, platelet counts increase/decrease in response to...

False; mild changes

T/F? High altitude, strenuous exercise, and menstruation cause large changes in platelet counts

150,000-400,000/cubic mm or 150-400 x 10^9/L (SI units)

What is a normal range for platelets?

<20,000/cubic mm (mm^3)

What is a critically low platelet count?

>1,000,000/cubic mm

What is a critically high platelet count?

Vasomotor symptoms (dizziness) and thrombosis/hemorrhage

What symptoms are common with a critically high platelet count (>1,000,000/cubic mm)?

Increased risk of spontaneous bleeding, petechia/purpura, and epistaxis

What symptoms are common with a critically low platelet count (<20,000/cubic mm)?

Asplenia, polycythemia, rheumatoid arthritis, iron deficiency anemia, and malignancies

What are pathologic causes of thrombocytosis (high platelet count)?

Spleen is gone and does not filter out old platelets, increasing total platelet count

Why does asplenia cause thrombocytosis?

Increases production of all blood cells, including platelets

Why does polycythemia cause thrombocytosis?

Bone marrow is ramped up to make RBCs, but has no iron to do so. However, platelets are still continuously produced

Why does iron deficiency anemia cause thrombocytosis?

Leukemia, lymphoma, and solid organ malignancies

What malignancies can cause thrombocytosis?

Sequestration, reduced production, accelerated destruction, consumption, loss from hemorrhage, dilution, and platelet clumping in an EDTA tube (pseudothrombocytopenia)

What are pathological causes of thrombocytopenia (decreased platelet count)?

Hypersplenism

What can cause sequestration of platelets, leading to thrombocytopenia?

Leukemia, myelofibrosis, and chemo drugs affecting bone marrow

What can cause a reduced production of platelets, leading to thrombocytopenia?

Antibodies, infections, drugs, and heart valves

What can cause accelerated destruction of platelets, leading to thrombocytopenia?

Disseminated intravascular coagulation (DIC)

What can cause consumption of platelets, leading to thrombocytopenia?

Sodium citrate tube

If platelet clumping occurs in an EDTA tube, what tube should the test be repeated in?