CBC

Question 1

On what sample is a CBC performed? Into what vial is it collected?

Answer 1

Whole blood in a K2-EDTA (purple top)

Question 2

What components of a CBC are direct counts?

Answer 2

WBC, RBC, HGB, PLT, MCV

Question 3

What components of a CBC are indirect counts?

Answer 3

HCT, RDW, MCH, MCHC, MPV

Question 4

What are the units for RBC and WBC counts?

Answer 4

X * 10^3 cells/ microliter

Question 5

How is the RBC affected by anemia? Polycythemia?

Answer 5

Decreased in anemia, and increased in polycythemia

Question 6

True or False: When the HGB concentration is abnormal, RBC count and HCT are also abnormal.

Answer 6

True

Question 7

How is HGB affected by anemia and polycythemia?

Answer 7

Decreased in anemia and increased in polycythemia

Question 8

What is hematocrit?

Answer 8

The relative volume of packed RBCs expressed as a percentage of whole blood

Question 9

How is hematocrit affected by anemia and polycythemia?

Answer 9

Decreased in anemia and increased in polycythemia

Question 10

What is the rule of three with regards to a CBC?

Answer 10

When RBCs are normal size, HGB and HCT correlate well with RBC such that HGB= RBC x 3 and HCT= HGB x 3

Question 11

What are the RBC indices?

Answer 11

Mean corpuscular volume; Mean corpuscular hemoglobin; Mean corpuscular hemoglobin concentration

Question 12

What is the differential diagnosis for decreased MCV?

Answer 12

Microcytic anemias, iron deficiency, thalassemias, anemia of chronic disease

Question 13

What could cause an elevated MCV?

Answer 13

Acute blood loss, reticulocytosis, hemolytic anemia, or liver disease

Question 14

What is the mean corpuscular hemoglobin?

Answer 14

The content (weight) of HGB in an individual RBC

Question 15

How is MCH affected by reticulocytosis?

Answer 15

Increases

Question 16

What is MCHC?

Answer 16

Mean corpuscular hemoglobin concentration is the average HGB concentration in a given volume of packed RBC (%)

Question 17

What are the only 2 conditions in which an increase in MCHC is observed?

Answer 17

Spherocytosis and cold agglutinins

Question 18

What is the term for the presence of a variation in RBC size?

Answer 18

Anisocytosis

Question 19

How can Thalassemia trait and iron deficiency anemia be distinguished through CBC?

Answer 19

Thalassemia trait will have a normal RDW and IDA will have a high RDW

Question 20

What term describes a variation in the shape of RBCs?

Answer 20

Poikilocytosis

Question 21

What term describes the presence of both poikilocytosis and anisocytosis?

Answer 21

Anisopoikilocytosis

Question 22

True or False: RDW is only decreased in very rare cases?

Answer 22

False- never decreased

Question 23

What is a reticulocyte count? What does it mean?

Answer 23

Reticulocytes are immature anuclear red cells and the count is an indication of bone marrow production efficacy

Question 24

True or False- very low or absent platelets are rarely present a clinical problem.

Answer 24

False- It indicates a dire situation

Question 25

What are the major general causes of thrombocytosis?

Answer 25

It can be reactive secondary to blood loss or primary due to myeloproliferative neoplasms

Question 26

True or False: Platelet size varies proportionally with platelet count.

Answer 26

False- varies inversely with platelet count

Question 27

What is the difference between a Total WBC and Corrected WBC?

Answer 27

Total counts all nucleated blood cells , including abnormal nucleated RBCs; a corrected WBC subtracts the abnormal NRBCs

Question 28

In what cases is a WBC increased?

Answer 28

Bacterial infections, myeloproliferative neoplasms, or leukemias

Question 29

In what cases is a WBC decreased?

Answer 29

Viral infections, leukemias, chemotherapy

Question 30

What is a differential WBC count?

Answer 30

A diff enumerates the number of each specific type of WBC