Hematology Final Review

Preanalytical phase testing

Any factors affecting the sample prior to testing

• Proper identification

• Collection procedure

• Transportation requirements

Analytical phase testing

encompasses all steps involved in the actual testing of a specimen, starting with preparation and ending with the verification of results

Postanalytical phase testing

Anything that occurs after the test has been ran

• Proper documentation

• Critical reporting

• Calculations post dilution

Reference values

a set of numerical limits—usually the central 95% of results—derived from testing a large group of healthy individuals

Delta checks

Comparison of current patient result and the patient’s previous result

Difference between abnormal and critical values

Abnormal values are test results outside the established normal reference range requiring follow-up, while critical values (or panic values) indicate a life-threatening, dangerous condition requiring immediate medical intervention

Calculating RBC indices

• MCV=Hematocrit/RBC*10

• MCH= Hemoglobin/RBC*10

• MCHC=Hemoglobin/hematocrit*100

Hematopoiesis sources throughout life cycle

Yolk sac: mesoblastic period—> Liver: hepatic period—>Spleen: hepatic period—> Bone marrow

4 main functions of the spleen

• Hematopoiesis

• Reservoir

• Filtration

• Immunologic

Bone marrow’s role in hematopoiesis

responsible for producing over 500 billion blood cells daily

Pluripotent stem cells—what they can differentiate to?

• Embryonic Stem Cells

• Induced Pluripotent Stem Cells

Role of EPO

• Functions as an erythroid growth factor

  • stimulates RBC production

Primary bone marrow source for collection

Iliac crest

Understanding CBC results

• High RBC/Hb/Hct: Potential dehydration, smoking, or heart/lung disease.

• Low RBC/Hb/Hct (Anemia): Possible bleeding, iron deficiency, or chronic disease.

• High WBC (Leukocytosis): Likely infection, inflammation, or leukemia.

• Low WBC (Leukopenia): Potential bone marrow issues, autoimmune disorders, or medication reaction.

• High Platelets: Potential infection or iron deficiency.

• Low Platelets: Risk of bleeding, possible liver issues, or medication side effects.

Approximate life span of a RBC

120 days

Anisocytosis

Variation in size

Poikilocytosis

Variation in shape

Polychromasia

Gray/blue in color

Hypochromia

Larger central pallor than normal red cell, >3µm

Spherocytes

• Compact RBCs

• Small, dense, and dark

• Spherical RBCs

Sickle cells

• Reversible: more rounded, half-moon shaped

• Irreversible: crescent shaped and pointed projections

Ovalocytes

• Egg shaped

• Thalassemia

• Megaloblastic anemia

Elliptocytes

abnormally elongated, oval, or "cigar-shaped" red blood cells caused by membrane protein defects

Target cells

Bull’s eye—shaped cell

Stomatocytes

• Elongated area of central pallor

• cup-shaped red blood cells with a characteristic slit-like or "fish-mouth" area of central pallor

Difference between acanthocytes & echinocytes (burr cells)

• Acanthocytes smaller red surrounded by uneven thorn-like spicules

  • 3-9 spikes

• Echinocytes have numerous, regularly spaced, short, sharp projections (burr cells) typically caused by uremia or storage artifacts

Howell-Jolly bodies

small, dark purple, spherical inclusions in red blood cells that consist of residual DNA remnants.

Pappenheimer bodies

abnormal, iron-containing purple/blue granular inclusions within red blood cells, representing excess iron not incorporated into hemoglobin

Basophilic stippling

• RNA & mitochondrial remnants

Significance of reticulocyte count and when is it used?

• measures immature red blood cells to evaluate how quickly the bone marrow produces them

• It is primarily used to diagnose the cause of anemia, distinguish between marrow production issues and blood loss, and monitor treatment responses

Heme molecule structure

• Four iron atoms in the ferrous state (Fe2+) in the center

  • Iron in the ferric state (Fe3+) cannot bind oxygen

• Porphyrin ring

Globin molecule structure

• Amino acids linked together

  • Forms a polypeptide chain

What kind of iron is required for properly functioning hemoglobin molecules

Ferrous iron (Fe2+)

Purpose and function of hemoglobin

• Primarily oxygen delivery

• Secondarily to pull CO2 away from the tissues

• Hemoglobin loads oxygen 1:1 in oxygen rich environments

• Unloading occurs in oxygen poor environments

Difference between Hgb F, Hgb A, & Hgb A2

• Hgb A is the adult hemoglobin type

• Hgb F is the main fetal hemoglobin

• Hgb A2 is a minor hemoglobin component

Main hemoglobin type in fetal development and infancy

Hgb F

Main hemoglobin type in adults

Hgb A

Why is carboxyhemoglobin so dangerous

• It prevents blood from carrying oxygen

• No releasing of the oxygen to the tissues

Why is sulfhemoglobins so dangerous

• Can be toxic at low levels

• hemoglobin doesn’t bind to O2 instead sulfhemoglobin

Extravascular hemolysis

• Accounts for 90% of hemolysis

• RBCs are destroyed and phagocytized

• Occurs in the:

  • Spleen

  • Liver

  • Lymph nodes

  • Bone marrow

Intravascular hemolysis

• Accounts for 10% of hemolysis

• Lysed directly in the blood vessel

Types of microcytic anemias

• IDA

• Sideroblastic

• Thalassemia

PBS characteristics of IDA

• Microcytic and hypochromic

• Small and deficient in hemoglobin

PBS characteristics of Sideroblastic anemia

• Presence of pappenheimer bodies

• Low reticulocyte count

PBS characteristics of Thalassemias

• marked microcytosis

• hypochromia

• target cells

• basophilic stippling

What classifies as macrocytic anemia

• low hemoglobin

• High MCH

• Normal MCHC

What does asynchrony in the BM mean

a maturation defect where the cell nucleus develops slower than the cytoplasm

Differentiation between megaloblastic and non-megaloblastic

• Megaloblastic MCV is extremely high whereas Non-megaloblastic MCV is slightly elevated

• Megaloblastic anemia is caused by impaired DNA synthesis via folic acid and Vitamin B12 deficiency

• Nonmegaloblastic anemia is caused by thyroid issues and liver disease

What organ causes spherocytes, how is this done

• The spleen

  • An antibody is attached to RBCs and is sheared off as it passes through the spleen, taking some of the membrane with it

Lifespan of spherocytes

10-30 days

What is a xerocyte

dehydrated, rigid RBCs that appear concentrated on one end

What is aplastic anemia

• Hypoproliferative disorder

• Pancytopenia

• Stressed BM with decreased cellularity

How to combat CBC irregularities from CAD

strict temperature management and specialized laboratory handling to prevent artificial, false-low red blood cell counts

How do sickle cells form

due to an inherited mutation in the beta-globin gene

What are the implications of a sickle cell crisis

• Viruses

• dehydration

• fever

• stress

• Bone necrosis

Which organ bears the burden of a sickle cell crisis

The spleen

Hemoglobin C crystals

• Bars of gold

• melt in splenic environments

Hgb C crystals—average lifespan of RBCs with this disease

40-60 days

Maturation sequence of the myelocytic lineage

Myeloblast—>Promyeloblast—>Myelocyte—>Metamyelocyte—>Band—>Segmented neutrophil

Relative vs. absolute WBC values

• Relative is the % of each WBC identified during 100 cell count

• Absolute takes WBC count into consideration by multiplying each WBC percentage by the patient’s total WBC

Mature lymphocytes

specialized white blood cells (B, T, or NK cells) that have completed maturation in primary lymphoid organs (bone marrow or thymus) and now circulate in the blood and peripheral tissues to defend the body.

Mature Eosinophils

• Can appear at the myelocytic stage

• Cytoplasm has large distinct red-orange specific granules with orange-pink cytoplasm

• Eccentric nucleus that is bilobed

• Allergy response

Mature basophils

• coarse, clumped, bilobed nucleus

• Cytoplasm is large with specific purple-black granules

• Histamine response

Mature monocytes

• Loose and lacy chromatin

• Abundant grey-blue cytoplasm

• Antigen presentation

Mature neutrophils

the most abundant type of white blood cell (50–70% of leukocytes) and act as the innate immune system's primary, short-lived defense, patrolling the blood for bacterial and fungal infections

neutrophilic precursor—Blast

• Round, oval nucleus

• light purple chromatin

• small blue cytoplasm

• 2-4 nucleoli present

neutrophilic precursors—promyelocytes

• Oval, round, flattened nucleus

• light purple chromatin

• Moderate blue cytoplasm with large blue-red granules

• Large, prominent nucleoli

neutrophilic precursors—Myelocytes

• Oval-indented nucleus

• Denser, red-purple chromatin with a coarser appearance

• specific or secondary granules present in cytoplasm

• last stage capable of dividing

neutrophilic precursors—metamyelocytes

• kidney bean shaped nucleus

• pale blue to pinkish cytoplasm

• No nucleoli

• condensed chromatin

neutrophilic precursors—bands

• C or S shaped chromatin

• Brown-pink cytoplasm

• Filament represents a meta but indentation is more than half of the nuclear margin

Left shift

Bone marrow is sending out younger and less mature cells

What causes increased neutrophils

• Infections/inflammatory responses

• Pregnancy

• Stress response

• Surgery

What causes increased eosinophils

• Skin disease

• Parasitic disease

• Transplant rejections

• Asthma

• Allergies

What causes increased basophils

• Myeloproliferative disorders

• Renal disease

• Ulcerative colitis

• Hypersensitivity reactions

What causes increased monocytes

• Malignancies

• Bone marrow failure

• Chronic infections

What causes increased lymphocytes

when the body is fighting an infection, reacting to inflammation, or experiencing significant stress

Toxic granulation in neutrophils

• Direct response to lysosome enzyme production

• Sometimes resembles Basophils

Vacuoles

• Appear in cytoplasm

• Prolonged drug exposure may lead to phagocytosis of granules

• Possible sepsis

Dohle bodies

• Cytoplasmic inclusions

  • Ribosomal RNA

• Appear due to rapid or stressful production

• rod-shaped, pale blue structures

Hypersegmentation

• >5 lobes

• Seen in megaloblastic processes

• Accompanied by oval macrocytes

Pelger-Huet Anomaly

• Peanut shaped or dumbbell shaped nucleus

• Spherical with no lobes

• May initially appear as bands or meta

• Fairly common inherited disorder

Main differences in acute leukemias and chronic leukemias

• Acute leukemia is more severe with quick and aggressive onset usually in blasts AND predominantly mature cells

• Chronic leukemia is less severe with insidious onset usually in predominantly mature cells

Myelodysplastic syndrome

a group of blood cancers occurring when immature blood cells in the bone marrow do not mature properly, resulting in low blood cell counts

Which leukemia has the highest cure rate

Hairy Cell Leukemia

Collagen role in hemostasis

• A potent stimulator for platelet activation

• Acting as the primary initiator of blood clotting when vascular injury exposes subendothelial collagen to blood flow

Endothelial’s role in hemostasis

The endothelium acts as a dynamic interface between blood and tissues, playing a crucial role in maintaining hemostasis by balancing anticoagulation and procoagulation

How many platelets come from ONE megakaryocyte

2000 platelets

Difference between platelet plug and fibrin clot

• A platelet plug is a rapid, temporary, and fragile seal formed during primary hemostasis.

• A fibrin clot is a slower, stable, and strong meshwork of fibrin protein that reinforces the plug during secondary hemostasis, ensuring permanent repairs

Primary vs. secondary hemostasis

• Primary hemostasis is the initial, rapid response to vascular injury, forming a temporary, weak platelet plug to stop bleeding.

• Secondary hemostasis follows immediately, using the coagulation cascade to create a stable, insoluble fibrin mesh that reinforces the plug into a solid clot

Intrinsic vs. extrinsic pathways

Intrinsic pathway is a slower process and is quantitatively significant process that involves factors XII, XI, IX, and VII. aPTT measures this pathway

Extrinsic pathway is a rapid process that involves Factors VII and III. PT measures this pathway.

Why does dysfunctional vWF cause impaired platelet adhesion

it fails to act as the essential molecular bridge between exposed subendothelial collagen and platelets, preventing their capture and anchoring at injury sites

How do platelets “call in the troops?”

to stop bleeding and initiate healing primarily through a rapid, complex chemical signaling process

Afibrinogenemia vs. hypofibrinogenemia vs dysfibrinogenemia

• Afibrinogenemia is homozygous autosomal recessive with <10 mg/dL in plasma and poor wound healing

• Hypofibrinogenemia is the heterozygous form of afibrinogenemia with 20-100 mg/dL in plasma and severe postoperative bleeding characterizes it.

• Dysfibrinogenemia is autosomal dominant and is inherited homo and heterozygously.

Why is thrombin a “jack of all trades”

It acts as the central hub of coagulation, switching between procoagulant (clotting) and anticoagulant (anti-clotting) roles, while also influencing inflammation and cell repair

What is the key component of clot dissolution

Plasminogen

What is the main fibrinolytic product measured in routine laboratories

D-dimer

Why is DIC so dangerous?

• Destroys clotting factors and platelets as soon as they are activated

• systemic excessive disposition of thrombi and hemorrhage

Why is heparin Xa superior to PTT

It directly measures heparin's anticoagulant activity, offering greater accuracy, faster time to therapeutic range, and fewer dose adjustments

What is measured for Warfarin and Coumadin therapy

the INR (International Normalized Ratio) and the PT (Prothrombin Time)

What is measured for heparin therapy

activated partial thromboplastin time (aPTT) to measure the blood's clotting time