Hematology - CBC

Question 1

Which blood type can receive anyone’s blood (universal recipient)?

Answer 1

AB+

Question 2

Which blood type can be given to anyone (universal donor)?

Answer 2

O-

Question 3

What is cross matching?

Answer 3

Done before a transfusion to catch antigens that are not routinely typed
Ensure the donor RBCs match recipient’s serum
A small amount of recipient serum is mixed with a small amount of donor RBCs
Examined under the microscope
Agglutination indicates incompatibility

Question 4

Direct Coombs’ Test

Answer 4

Test the fetal RBCs (cord blood) using anti-human globulin to bind anti-RhD antibodies on the surface of these fetal RBCs that have crossed the placental blood barrier
Diagnoses Hemolytic Disease of the Newborn (HDN)

Question 5

Indirect Coombs’ Test

Answer 5

Tests for anti-RhD antibodies in the birth parent’s serum
Used to identify and prevent possible HDN in future pregnancies if the first born is Rh+ and there is a possible fetal-maternal blood transfusion

Question 6

Types of Transfusion Products

Answer 6

Whole Blood
Packed Red Cells
Leukocyte-Poor RBC
Platelet Concentrates
Granulocyte Concentrates
Fresh Frozen Plasma
Factor Concentrates

Question 7

Packed RBC

Answer 7

most commonly used blood product; 1 unit can increase a patient’s hematocrit by 3-5%
Whole blood is spun down, and plasma removed; packed = hematocrit is now 70-80%
Indications:
O2 deprivation
Profoundly fatigued due to anemia
Kidney not synthesizing adequate EPO
Improper bone marrow function

Question 8

Leukocyte-poor RBC

Answer 8

WBC removed to reduce transfusion reactions – contains no HLA molecules
Immunogenic HLA molecules can induce chills and fever
Receiving products with WBC may develop memory cells and increase risk if future transfusion is needed
Indications:
Patient has had 2 documented febrile reactions
Patient may require multiple transfusions
Patient may require a transplant

Question 9

Transfusion reaction examples?

Answer 9

Transfusion reactions
Hemolytic transfusion reaction due to RBC-antibody reaction
Febrile non-hemolytic transfusion reaction
Transfusion-associated acute lung injury
Prevent with Type & Crossmatch (ABO and Rh)
Blood-borne Pathogens / Infectious Diseases – HIV, Hep B & C, Malaria
Allergic Anaphylaxis – WBC-mediated febrile reactions
Circulatory overload
Religious objections to blood transfusion

Question 10

Alternatives to transfusion

Answer 10

Autologous Transfusions
No risk alloimmunization or infectious disease
Best with elective surgery – patient would donate before surgery for use during surgery

Directed Transfusions
Solicit donations from family/friends – blood will still be screened
Thought to be safer than anonymous transfusion products but not necessarily

Question 11

platelet concentrations

Answer 11

One bag contains platelets from 4-6 donors of the same blood type and is only viable for 5 days
Indications:
Thrombocytopenia
Platelet dysfunction
Chemotherapy
Contraindications:
Disseminated Intravascular Coagulation (DIC) – quick depletion of platelets due to excessive clotting
Idiopathic Thrombocytopenic Purpura (ITP) – immune system attacks platelets

Question 12

fresh frozen plasma

Answer 12

Contains all coagulation factors in normal amounts
Free of RBCs, WBCs, and Platelets
Indication: documented coagulation factor deficiencies who are actively bleeding OR who are about to undergo an invasive surgery
Must be ABO compatible with the recipient
Rh type does not need to be considered

Question 13

Factor concentrates

Answer 13

Most commonly administered blood factors are:
Factor VIII Concentrates – commercially prepared, lyophilized powder purified from human plasma to treat Hemophilia A or von Willebrand Disease (VWD)
Factor IX Concentrates – commercially prepared, lyophilized powder purified from human plasma to treat Hemophilia B
Current preparation process and screening eliminate risk of HIV, HBV and HCV transmission
Recombinant (synthetic) human factors is purified from genetically engineered non-human cells grown in tissue culture.
Recombinant von Willebrand Factor was approved by FDA in 2018

Question 14

Leukocytosis

Answer 14

infections, sepsis, cancers, drug reaction, etc.

Question 15

Leukopenia

Answer 15

viral infections, overwhelming bacterial infections, chemo/radiation, bone marrow failure

Question 16

Critical values

Answer 16

Critical values:
Below 0.5 x 10E3/uL - extremely dangerous and often fatal
Below 2.0 x 10E3/uL
Above 30.0 x 10E3/uL

Question 17

Neutrophils

Answer 17

• most numerous
• bacterial infections * important for inflammation
• immature form is called “band cells” refers to nucleus not yet segmented.

Question 18

Neutrophil clinical significance

Answer 18

Neutrophilia: acute bacterial infections, inflammation, tissue necrosis
Neutropenia: an acute overwhelming bacterial infection (poor prognosis), viral infections (mono, hepatitis, measles, etc), cytotoxic/immunosuppressive drugs, organic solvents, nutritional deficiencies (folate, B12, copper)
Reference value: 50-70%
0-5% are band cells

Question 19

Lymphocytes

Answer 19

Migrate to areas of inflammation in both early and late stages
Produce serum immunoglobulins
Plays an important role in immunologic reaction/response
All lymphocytes are made in the bone marrow

Question 20

Clinical significance of Lymphocytes

Answer 20

Lymphocytosis: leukemia, viral infections (CMV, EBV, HIV, hepatitis)
Lymphopenia: chemo, lymphoma, steroid use, aplastic anemia, AIDS
Reference value: 30-45%

Question 21

Lymphocytes

Answer 21

B Cells: mature in bone marrow
Regulates antigen-antibody response that is specific to the offending antigen; remembers offending antigens
Fully differentiated B cells = plasma cells, produces antibodies (in bone marrow and inflamed tissues only)

T Cells: mature in thymus
CD4+ helper T cells, natural killer T cells, CD8+ suppressor T cells, cytotoxic T cells

Question 22

Eosinophils

Answer 22

Primary used to diagnose allergic reactions and (large) parasitic infections
Monitor severity and treatment efficacy
Granules contain histamines
Clinical significance: increased in allergies, hay fever, asthma, parasitic infections (those that invade tissues, like worms), chronic skin diseases and inflammatory bowel diseases (Crohn’s and Ulcerative Colitis)

Reference value: 0-3%

Question 23

Monocytes

Answer 23

Largest cells of normal blood
Second line of defense against infection by phagocytosing injured and dead cells, microorganisms, and insoluble particles from circulating blood (scavenger for debris)
Produces interferon
Clinical Significance:
Increased: > 600/uL in bacterial infections, TB, subacute bacterial endocarditis, and syphilis

Reference value: 0-6%

Question 24

Basophils

Answer 24

Least numerous WBCs
With granules that contain heparin, histamines, and serotonin
Clinical significance:
Increased: basophilic leukemia, Hodgkin’s lymphoma
May be implicated in IgG mediated anaphylaxis due to allergens
Decreased: hyperthyroidism

Reference value: 0-1%

Question 25

Red Blood Cell Count (RBC)

Answer 25

Function: indirectly measures the oxygen carrying capacity of blood.
Hemoglobin
Provides information on the adequacy of RBC production
Stimulated by EPO and RBC recycled/eliminated by the spleen
Reported by the number of RBCs per cubic millimeter of blood
Performed by automated electronic counters

Reference value:
4.2-5.9 x 10E6/uL

Question 26

RBC clinical implications

Answer 26

Clinical Implications:
Low RBC: anemia, hemoglobinopathy, hemolysis, cirrhosis, artificial heart valves, renal disease, leukemia, myeloma, Hodgkin’s lymphoma, etc.
High RBC: polycythemia vera

Question 27

RBC interfering factors

Answer 27

Higher altitude and smoking –> increase
Pregnancy (hemodilution) –> decrease
Medication –> increase OR decrease
Improper venipuncture (prolonged venous stasis) –> falsely high
Wrong collection tube –> invalid if clotted

Question 28

Hemoglobin

Answer 28

Amount of hemoglobin in a volume of blood (g/dL)
Directly measures the O2 carrying ability of the blood
Normal adult hemoglobin A is comprised of 4 heme groups & 4 polypeptide (globin) chains
Each heme group contains iron and binds to 1 molecule of O2
Can be measured in-office as an indirect anemia screen
Reference values:
Females: 12-16 g/dL
Males: 14-17 g/dL

Question 29

Hematocrit clinical significance

Answer 29

Clinical Significance:
Decreased Hct: anemia, volume expansion (IV, pregnancy)
Increased Hct: polycythemia, dehydration (false elevation), COPD

Reference values:
Females: 36-47%
Males: 41-51%

Question 30

hematocrit

Answer 30

The red blood cell volume expressed as a percentage of the whole blood volume
Depends on the number of RBCs and their size
An indirect estimate of the RBC mass

Question 31

MCV

Answer 31

mean corpuscular volume

Average volume of an RBC
MCV = Hct x 10 / RBC count
Reference range: 80-98 fL (10E-15)

Classification by size:
Normocytic –> RBC size appears normal
Microcytic –> smaller than normal
Macrocytic –> larger than normal

Question 32

Macrocytic:

Answer 32

Megaloblastic anemia (B12/folate deficiency), chronic liver disease, chronic alcoholism, pernicious anemia, hypothyroidism

Question 33

microcytic anemia

Answer 33

Microcytic: iron deficiency anemia, thalassemia, sideroblastic anemia

Question 34

Normocytic:

Answer 34

hemolytic anemia, aplastic anemia , anemia of chronic disease (can also be microcytic), acute blood loss

Question 35

Mean corpuscular hemoglobin (MCH)

Answer 35

Average weight of hemoglobin in each RBC.
MCH: Hgb x 10 / RBC count
Reference range: 28-32 pg

Clinical Significance:
Follows closely with MCV
Increased MCH: macrocytic anemia
Decreased MCH: microcytic anemia

Question 36

Red cell distribution width (RDW)

Answer 36

Measures degree of RBC size variation
Abnormal variation in size is called anisocytosis
Normal RBCs have a small degree of variation
Clinical significance: the higher the number, the greater the variation in size
Often the first indication of anemia development

Reference range: 9.0-14.5 %
Slightly higher in those assigned female at birth

Question 37

Mean corpuscular hemoglobin concentration (MCHC)

Answer 37

Average concentration (amount) of hgb in the RBCs.
MCHC = Hgb x 100 / Hct
Reference range: 33-36 g/dL
Cannot be higher than 37 g/dL

Clinical Significance:
Decreased MCHC: hypochromic anemia
Increased MCHC: hyperchromic anemia
RARE: hereditary spherocytosis

Question 38

platelet count

Answer 38

Number of platelets per cubic mm (uL) of whole blood
Platelets/thrombocytes are necessary for blood clotting, vascular integrity, vasoconstriction, and formation of platelet plugs that occlude breaks in small vessels

Question 39

platelet count clinical significance

Answer 39

Clinical Significance:
Decr(ITP), anemias (pernicious, aplastic, hemolytic), viral and bacterial infections (including HIV), chemo and radiation, congestive heart failure
Increased: essential thrombocytosis/primary thrombocythemia, CML, polycythemia vera, SLE, rheumatoid arthritis
Malignancy is found in 50% of patients with unexpected platelet increase

Reference value:
140-400 x 10E3/uL
eased: disseminated intravascular coagulation (DIC), idiopathic thrombocytopenic purpura