BOC HEME-COAG

What are the primary anatomical sites of active adult hematopoiesis?

The red marrow of flat bones: skull, sternum, pelvis, ribs, and vertebrae

During prenatal development, what is the primary site of hematopoiesis between the 2nd and 7th months of gestation?

The liver (with minor contribution from the spleen).

Name the major growth factor driving the differentiation of the CFU-E pathway into mature erythrocytes.

 Erythropoietin (EPO)

Name the major growth factor responsible for stimulating megakaryocytopoiesis and platelet production from CFU-MK

Thrombopoietin (TPO)

Place the stages of granulocyte maturation in the correct order starting from the earliest committed precursor.

Myeloblast → Promyelocyte → Myelocyte → Metamyelocyte → Band Neutrophil → Segmented Neutrophil.

Which cell maturation line arises from the Common Lymphoid Progenitor (CLP)?

Lymphocytes (Natural Killer cells, T cells, and B cells, which further differentiate into plasma cells)

What is the primary plasma protein responsible for transporting iron in the body?

Transferrin

Name the two main storage forms of iron and specify which one is water-soluble.

• Ferritin (Major storage form; water-soluble)

• Hemosiderin (Long-term storage form; water-insoluble)

What clinical conditions or organ damage can result from excessive iron storage in tissues?

• Hemosiderosis and Hemochromatosis

Accumulation of early heme precursors (such as δ-ALA or porphobilinogen) causes what type of clinical symptoms, and what classic condition does it represent?

Neuropsychiatric symptoms; characteristic of Acute Intermittent Porphyria (AIP)

Accumulation of later heme precursors (Uroporphyrin, Coproporphyrin, Protoporphyrin) causes what distinct types of clinical symptoms?

Cutaneous symptoms (e.g., extreme photosensitivity, blistering, and facial hair/hypertrichosis).

Use the text's mnemonic path to sequence the intermediate steps of heme synthesis from start to finish.

δ-ALA → Porphobilinogen (PBG) → Uroporphyrinogen → Coproporphyrinogen → Protoporphyrin → Heme

Which specific enzymatic steps or intermediates in the heme synthesis pathway are directly inhibited by lead poisoning?

~ Conversion of δ-aminolevulinic acid (δ-ALA)

~ Conversion of Coproporphyrinogen

~ Incorporation of iron into Protoporphyrin (via ferrochelatase)

What happens to red blood cells (RBCs) and the calculated hematocrit value if a microhematocrit tube contains excess EDTA due to an underfilled sample?

Excess EDTA causes RBC shrinkage due to hypertonicity, leading to a falsely decreased hematocrit reading.

How do inadequate centrifugation time or a failure to properly seal the clay plug affect a manual microhematocrit result?

• Inadequate centrifugation leads to trapped plasma, causing a falsely increased hematocrit.

• Failure to seal the clay plug allows RBCs to escape during spinning, causing a falsely decreased hematocrit.

What are the three primary physiological sources of error that cause a falsely elevated total hemoglobin result when using standard spectrophotometric methods (e.g., cyanmethemoglobin)?

1. Lipemia / Icterus (increases turbidity/sample absorbance)

2. Extremely high White Blood Cell (WBC) count (causes light scattering)

3. Resisting hemoglobins (e.g., Hb SS, Hb CC, which fail to lyse easily)

Match the routine hematology anticoagulants to their mechanism of action:

1. EDTA

2. Heparin

1. EDTA: Chelates calcium (Ca++) to prevent coagulation

2. Heparin: Acts as an anti-thrombin agent

What causes a Left Shift in the Hemoglobin-Oxygen Dissociation curve, and what does it mean for tissue oxygenation?

Causes: Decreased CO₂, increased pH (alkalosis), decreased temperature, decreased 2,3-DPG, or high presence of Hemoglobin F (Hb F).

Meaning: Increased oxygen affinity; hemoglobin won't let go of O₂, leading to decreased tissue oxygen delivery.

What causes a Right Shift in the Hemoglobin-Oxygen Dissociation curve, and what does it mean for tissue oxygenation?

Causes: Increased CO₂, decreased pH (acidosis), increased temperature, or increased 2,3-DPG.

Meaning: Decreased oxygen affinity; hemoglobin releases O₂ more easily, leading to increased tissue oxygen delivery ("Won't Hold Tight").

What state is iron in within Methemoglobin, what color is the blood, and can it transport oxygen?

Iron is oxidized to the ferric state (Fe+++). The blood appears chocolate brown in color, and it cannot bind oxygen

What condition causes elevated Carboxyhemoglobin, and what characteristic color is observed in the patient's blood?

 Carbon monoxide poisoning (or heavy smoking). The blood turns a distinct cherry-red color

What is the predominant hemoglobin type in a normal adult, what are its constituent globin chains, and what is its approximate reference percentage?

Hemoglobin A (Hb A); composed of α₂β₂ chains; comprises approximately 97% of total adult hemoglobin

MCV Equation & Reference Range

Formula: (HCT × 10) / RBC
Range: 80-100 fL

MCH Equation & Reference Range

Formula: (HGB × 10) / RBC
Range: 28-32 pg

MCHC Equation & Reference Range

Formula: (HGB × 100) / HCT
Range: 32-36% (or g/dL)

Causes of MCHC >36% (Artifacts vs Pathology)

• Cold agglutinins

• Lipemia

• Icterus

• Spherocytosis

Lab Finder for RDW Elevation Significance

Indicates Anisocytosis (variation in RBC size)

Hemocytometer Total Volume Formula

Volume = length × width × depth × # of squares

Standard Neubauer Hemocytometer Chamber Depth

0.1mm

Total Volume Counted for Large WBC Squares (9 Squares)

0.9 mm³

Total Volume Counted for Center Platelet Square (25 Small Squares)

0.1 mm³

What causes a peripheral blood smear to appear too blue under Wright stain?

• Buffer or stain pH is too basic (alkaline).

• Prolonged staining time

What causes a peripheral blood smear to appear too red under Wright stain?

• Buffer or stain pH is too acidic.

• Prolonged washing time.

What are the four primary components of a Wright (Romanowsky) stain and their functions?

• Methanol: Fixative

• Phosphate buffer: Controls pH (ideal is 6.4)

• Eosin: Acidic dye (stains RBCs and eosinophil granules red/orange)

• Methylene blue: Basic dye (stains WBC nuclei and platelets blue/purple)

What is the formula to calculate an Absolute WBC Count from a differential percentage?

Relative Value (% as a decimal) × Total WBC Count

A patient has a Total WBC count of 8,000/µL and 70% neutrophils on their differential. What is their absolute neutrophil count?

5,600/µL (0.70 × 8,000)

Which condition is classically associated with hypersegmented neutrophils (>5 lobes)?

Megaloblastic anemia (Vitamin B12 or folate deficiency)

What benign hereditary condition (or acquired state in AML/AIDS) is characterized by hyposegmented neutrophils (dumbbell-shaped or single-lobed nuclei)?

Pelger-Huët anomaly (or Pseudo-Pelger-Huët)

The triad of toxic granulation, cytoplasmic vacuoles, and Döhle bodies in neutrophils indicates what clinical state?

Severe bacterial infection, sepsis, burns, or recent chemotherapy

 What are Döhle bodies composed of structurally?

Aggregates of rough endoplasmic reticulum (RNA) located in the cytoplasm of neutrophils

Variant (reactive/atypical) lymphocytes showing increased size and peripheral basophilia are most characteristically seen in which infection?

Infectious Mononucleosis (Epstein-Barr Virus)

Match the following leukocyte elevations to their primary diagnostic associations:

1. Eosinophilia

2. Neutrophilia

3. Lymphocytosis

4. Monocytosis

1. Eosinophilia: Allergies and parasitic infections

2. Neutrophilia: Acute bacterial infections

3. Lymphocytosis: Viral infections

4. Monocytosis: Tuberculosis (TB), syphilis, or malignancies

What is the formula used to correct a white blood cell count when ≥ 5 nucleated RBCs (nRBCs) are seen per 100 WBCs?

(Uncorrected WBC × 100) / (100 + # nRBCs per 100 WBCs)

Which abnormal RBC shape is a primary diagnostic marker for Disseminated Intravascular Coagulation (DIC) and hemolytic processes?

Schistocyte (RBC fragment)

Seeing Acanthocytes (spur cells) on a peripheral blood smear is highly characteristic of which genetic lipid disorder?

Abetalipoproteinemia (also seen in severe liver disease)

Macroovalocytes combined with hypersegmented neutrophils point directly to what class of anemia?

Megaloblastic Anemia (Vitamin B12 or Folate deficiency)

Echinocytes (Burr cells) are commonly associated with which metabolic renal condition?

Uremia (or as an alkaline glass artifact)

Which cell shape is a key feature of Hereditary Spherocytosis and ABO Hemolytic Disease of the Newborn (HDN)?

Spherocyte

Target cells (Codocytes) are most frequently seen in liver disease and which hemoglobin synthesis disorder?

Thalassemia (and other hemoglobinopathies like Hb C)

Teardrop cells (Dacryocytes) are classically associated with what bone marrow phenomenon?

Extramedullary Hematopoiesis (myelofibrosis)

What crystalline shape is characteristic of Hemoglobin C (Hb C) on a stained smear?

Bar-shaped hexagonal crystals

Which hemoglobinopathy produces crystals described as "hand in glove" or "Washington monument" shapes?

Hemoglobin SC disease

Which RBC inclusion is composed of denatured hemoglobin and is NOT visible on a standard Wright-stained smear?

Heinz bodies. They require a supravital stain (like New Methylene Blue or Brilliant Cresyl Blue) for visualization

What is the chemical composition of Howell-Jolly bodies and what clinical condition are they strongly tied to?

Composed of DNA remnants. Most frequently seen post-splenectomy or in severe hemolytic/megaloblastic anemias

What type of anemia is specifically indicated by the presence of Pappenheimer bodies, and how do you confirm them?

Associated with Sideroblastic anemia. Confirm their presence using a Prussian Blue stain(where they are called siderotic granules)

Basophilic stippling consists of aggregates of what substance, and what classic poisoning does coarse stippling indicate?

Composed of RNA (aggregated ribosomes). Coarse stippling is a classic indicator of Lead Poisoning

If an automated hematology analyzer outputs a severely elevated MCHC (>36.0 g/dL), an elevated MCV, and a decreased RBC count, what is the likely culprit?

Cold Agglutinin Disease (autoantibodies causing RBCs to clump together into a fake "giant cell")

What is the correct corrective laboratory action when a sample fails the Rule of Three due to a suspected cold agglutinin?

Warm the sample to 37°C in an incubator for 15-30 minutes and immediately rerun the CBC

What are the two fundamental mathematical equations comprising the hematology Rule of Three?

Hb × 3 = Hct ± 3%

RBC (in millions) × 3 = Hb ± 0.5

Which type of stain is used for manual reticulocyte counts?

Supravital stains (specifically, New Methylene Blue or Brilliant Cresyl Blue).

What effect does a tilted ESR tube have on the final result?

Falsely increases the ESR value

How does excess EDTA anticoagulant affect an Erythrocyte Sedimentation Rate (ESR)?

Falsely decreases it (causes RBC shrinking)

What is the formula for calculating the Corrected Reticulocyte Count?

(% Reticulocytes × Patient Hematocrit) / 45

An RPI value less than 2 (\(<2\)) indicates what clinical status?

Inadequate bone marrow response to anemia

What is the migration order of hemoglobins on Cellulose Acetate (alkaline pH 8.6) from cathode (-) to anode (+)?

C ➔ S ➔ F ➔ A

~ Crawl, Slow, Fast, Accelerate (C is closest to cathode; A is closest to anode)

What hemoglobins migrate together with HbS at an alkaline pH (8.6)?

HbD and HbG

What hemoglobins migrate together with HbC at an alkaline pH (8.6)?

HbE and HbO (as well as A₂)

What is the migration order of hemoglobins on Citrate Agar (acid pH 6.2) from anode (+) to cathode (-)?

C ➔ S ➔ A ➔ F

~ Sad Dog Gets Loved (A₂, CE Of Clubs / Sad Dog / Gets / Loved = F)

What amino acid substitution causes Hemoglobin S?

Valine substituted for Glutamic acid at the 6th position of the beta chain

What amino acid substitution causes Hemoglobin C?

Lysine substituted for Glutamic acid at the 6th position of the beta chain

What screening test is used for HbS, and what does a positive result look like?

Dithionite solubility test (Sickle Dex). A positive result produces turbidity (cloudiness) because HbS precipitates.

What is the normal Myeloid to Erythroid (M:E) ratio in a healthy adult bone marrow?

3:1 to 4:1

What does a decreased M:E ratio indicate?

Erythroid hyperplasia (or myeloid hypoplasia). Common in hemolytic anemia and erythroleukemia.

What does an increased M:E ratio indicate?

Myeloid hyperplasia. Common in myeloid leukemias and infections.

If a bone marrow collection results in a "Dry Tap," what pathognomonic conditions should you suspect?

Aplastic anemia or Myelofibrosis

Which specimen type is required for the overall evaluation of bone marrow cellularity?

Core Biopsy (rather than the aspirate).

What are the characteristic shapes associated with Homozygous Hemoglobin C crystals?

Bar-shaped, "hand-in-glove," or "Washington Monument" structures

What is the specific amino acid substitution that causes Hemoglobin S (Sickle Cell)?

Valine replaces Glutamic Acid ("Se*y Valine")

A deletion of 3 alpha globin genes (- - / -α) results in what condition and what type of RBC inclusion?

Hemoglobin H (Hb H) disease characterized by Heinz bodies

A deletion of all 4 alpha globin genes results in what fatal condition?

Hydrops fetalis (causing nonviable fetus)

Based on the MCV flowchart, what are the two main categories of structural defects that cause a Low MCV (Microcytic) anemia?

Problems with Heme (e.g., Iron Deficiency, Sideroblastic) and Problems with Globin (e.g., Thalassemias)

How do Cellulose Acetate and Citrate Agar electrophoresis steps differ regarding Hemoglobin C?

On Cellulose Acetate, Hb C migrates closely with A2, E, and O; Citrate Agar separates Hb C from the others to confirm the diagnosis

A patient presents with a microcytic, hypochromic anemia. Lab results show decreased Serum Iron, increased TIBC, and decreased Ferritin. What is the diagnosis?

•  Iron Deficiency Anemia (IDA).

  • BOC Pearl: Ferritin is the most sensitive indicator of iron deficiency. If TIBC is decreased and Ferritin is normal to increased, think Anemia of Chronic Inflammation.

Both Vitamin B12 and Folate deficiencies present with macrocytosis, oval macrocytes, and hypersegmented neutrophils. What metabolic panel values specifically confirm a Vitamin B12 deficiency over Folate?

• Increased Methylmalonic Acid (MMA) AND increased Homocysteine.

  • BOC Pearl: In Folate deficiency, only Homocysteine is elevated; MMA remains normal. Pernicious anemia (a cause of B12 deficiency) will also show positive Anti-IF (Intrinsic Factor) antibodies.

A patient experiences acute hemolysis after taking oxidizing anti-malarial drugs. The peripheral smear reveals Heinz bodies and bite cells. What enzyme deficiency is responsible?

• G6PD Deficiency (Glucose-6-Phosphate Dehydrogenase).

  • BOC Pearl: Heinz bodies are composed of precipitated, denatured hemoglobin. They are invisible on a standard Wright's stain and require a supravital stain (like New Methylene Blue or Crystal Violet) to be visualized.

• Which congenital RBC membrane defect is characterized by an increased MCHC (>36%), an abnormal Spectrin network, and an increased osmotic fragility test?

• Hereditary Spherocytosis (HS).

  • BOC Pearl: Spherocytes lack central pallor due to membrane loss caused by molecular defects in spectrin or ankyrin.

A patient's CBC reveals a severe normocytic anemia accompanied by marked thrombocytopenia (low platelets). The peripheral blood smear shows prominent schistocytes. What broad classification of conditions does this represent?

• Microangiopathic Hemolytic Anemia (MAHA).

  • BOC Pearl: This presentation is a classic hallmark for medical emergency conditions including HUS (Hemolytic Uremic Syndrome), TTP (Thrombotic Thrombocytopenic Purpura), and DIC(Disseminated Intravascular Coagulation). Schistocytes represent fragmented RBCs broken by fibrin strands in microvessels.

Pelger-Huët Anomaly characteristics and function

• Hyposegmented neutrophils.

• Pince-nez appearance.

• Normal cell function.

Chediak-Higashi Syndrome key features

• Giant abnormal lysosomes.

• Albinism association.

• Severe recurrent infections.

May-Hegglin Anomaly triad

• Large/giant platelets.

• Thrombocytopenia (low count).

• Döhle-like leukocyte inclusions

Alder-Reilly Anomaly classic association

• Large azurophilic granules.

• Mucopolysaccharidoses disease.

• Mimics toxic granulation.

Kleihauer-Betke Acid Elution purpose

• Measures fetal hemoglobin resistance.

• Detects fetal-maternal hemorrhage.

• Quantifies RhIg dosage.

Donath-Landsteiner Test indications

• Paroxysmal Cold Hemoglobinuria (PCH).

• Biphasic IgG autoantibody.

• Anti-P blood group specificity

FLAER and Flow Cytometry diagnostic target

• Paroxysmal Nocturnal Hemoglobinuria (PNH).

• Looks for CD55/CD59 deficiency.

• High sensitivity marker

Polycythemia Vera (Primary Erythrocytosis) vs. Secondary Erythrocytosis EPO levels

• Primary: Decreased EPO levels.

• Secondary: Increased EPO levels.

• Driven by tissue hypoxia.

What primary cytochemical stain/score differentiates a Leukemoid Reaction from CML?

LAP score (Leukocyte Alkaline Phosphatase). It is elevated in a leukemoid reaction and decreased in CML

Which cytogenetic translocation is associated with Acute Promyelocytic Leukemia (APL / FAB M3)?

t(15;17), which involves the retinoic acid receptor alpha-gene

What classic morphological structures are found in the cytoplasm of blasts in AML/M3?

Auer rods (bundles of them are called faggot cells)

What is the minimum blast percentage required to diagnose acute leukemia under the WHO classification?

≥ 20% blasts in the peripheral blood or bone marrow

What genetic mutation is characteristically positive in Polycythemia Vera (PV)?

JAK2 mutation ("JAK loves Poly Vera")