Comprehensive Hematology Review and Reference Ranges

Erythrocytes

O2 transport

Granulocytes

Defense against bacterial infection

Lymphocytes

Cellular & humoral immunity

Platelets

Coagulation

WBC

4.5-11.5 × 10^3/µL or 4.5-11.5 × 10^9/L

RBC Male

4.6-6 × 10^6/µL or 4.6-6 × 10^12/L

RBC Female

4-5.4 × 10^6/µL or 4-5.4 × 10^12/L

HGB Male

14-18 g/dL or 140-180 g/L

HGB Female

12-15 g/dL or 120-150 g/L

HCT Male

40%-54% or 0.40-0.54 L/L

HCT Female

35%-49% or 0.35-0.49 L/L

MCV

80-100 fL

MCH

27-31 pg

MCHC

32%-36% or 32-36 g/dL

PLT

150-450 × 10^3/µL or 150-450 × 10^9/L

RBCs Birth

4.10-6.10 × 10^12/L

RBCs 1-2 MO

3.4-5 × 10^12/L

RBCs 1-3 YR

3.4-5.2 × 10^12/L

RBCs 8-13 YR

4-5.4 × 10^12/L

HGB 1-2 MO

16.5-21.5 g/dL

HGB 1-3 YR

10.6-16.4 g/dL

HGB 8-13 YR

9.6-15.6 g/dL

HGB ADULT

12-15 g/dL

Segs %

37-67%

Bands %

3-11%

Lymphs %

18-38%

Orthochromic normoblast

Normally confined to bone marrow.

Metarubricyte

8-12 µm. N:C ratio 1:2. Nucleus is pyknotic. Last nucleated stage. Normally confined to bone marrow.

Polychromatophilic erythrocyte

Reticulocyte: 7-10 µm. No nucleus. Cytoplasm is diffusely basophilic (bluish tinge). Reticulum seen with supravital stain. 0.5%-1.5% of RBCs in adult peripheral blood.

Mature erythrocyte

7-8 µm. Biconcave disk. Reddish-pink cytoplasm with area of central pallor 1/3 diameter of cell.

Megaloblastic

Vitamin B12 or folic acid deficiency. Nucleus lags behind cytoplasm in maturation. Cells grow larger without dividing. Example: Pernicious anemia.

Iron deficiency

Cytoplasm lags behind nucleus in maturation due to inadequate iron for hgb synthesis. Example: Iron deficiency anemia.

Hemoglobin A

2 α, 2 β chains. Adult reference value: >95%. Newborn reference value: 20%.

Hemoglobin A2

2 α, 2 δ chains. Adult reference value: 1.5%-3.7%. Newborn reference value: <1%.

Hemoglobin F

2 α, 2 γ chains. Adult reference value: <2%. Newborn reference value: 50%-85%.

Hemoglobin S

Valine substituted for glutamic acid in 6th position of β chain. Reference value: 0.

Hemoglobin C

Lysine substituted for glutamic acid in 6th position of β chain. Reference value: 0.

Methemoglobin

Iron oxidized to ferric (Fe3+). Can't bind O2. Cyanosis, Heinz bodies. Treat with methylene blue. Total HGB: ≤1%.

Sulfhemoglobin

Sulfur bound to heme. O2 affinity 1/100th of normal. Can't be converted back to normal. Total HGB: 0.

Carboxyhemoglobin

Carbon monoxide bound to heme. ↓O2 to tissues. A#nity of hgb for CO is 200× greater than for O2. Total HGB: <1%.

Anisocytosis

Variation in size. Seen in many anemias.

Macrocytes

RBCs >9 µm. Seen in megaloblastic anemias, liver disease, reticulocytosis. Normal in newborns.

Microcytes

RBCs <6 µm. Seen in iron deficiency anemia, thalassemia, anemia of chronic infections.

Poikilocytosis

Variation in shape. Seen in many anemias.

Elliptocytes/ovalocytes

Oval or pencil/cigar shaped. Membrane defect. Seen in hereditary ovalocytosis, various anemias.

Crenated RBCs

Round cell with knobby, uniform projections. Osmotic imbalance.

Burr cells (echinocytes)

Round cell with evenly spaced blunt or pointed projections. Membrane defect. Seen in uremia, pyruvate kinase deficiency.

Acanthocytes (spur cells)

Small, dense cells with irregularly spaced projections of varying length. Seen in severe liver disease, abetalipoproteinemia.

Schistocytes

RBC fragments. RBCs split by fibrin strands. Seen in microangiopathic hemolytic anemias (DIC, TTP, HUS), prosthetic heart valves.

Sickle cells (drepanocytes)

Crescent, S or C shaped, boat shaped. Seen in sickle cell anemia.

Hemoglobin C crystals

Blunt, 6-sided, dark-staining projection. Seen in hemoglobin C disease.

Hemoglobin SC crystals

Glove-like intracellular crystals. Seen in hemoglobin SC disease.

Teardrops (dacryocytes)

Teardrop shaped. Seen in myelofibrosis, thalassemia & other anemias.

Hypochromia

Central pallor >1/3 cell diameter. Seen in iron deficiency anemia, thalassemia.

Anisochromia

Mixture of normochromic & hypochromic RBCs. Seen in dimorphic anemia, post-transfusion.

Polychromasia

Bluish-gray color. Young RBCs. Retics with supravital stain. Sign of active erythropoiesis. 1%-2% in normal adult.

Bull's-eye, "Mexican hat cell"

Target cells (codocytes) - Hemoglobinopathies, thalassemia, liver disease. May be artifact if observed in only 1 part of smear.

RBC with slit-like central pallor

Stomatocytes - Hereditary stomatocytosis, hereditary spherocytosis, thalassemia, alcoholic cirrhosis, Rh null disease. May be artifact in parts of smear that are too thin or too thick.

Spherocytes

Small, dark-staining RBCs without central pallor - Membrane defect. Hereditary spherocytosis, autoantibodies, burns, hemoglobinopathies, hemolysis, ABO HDN, incompatible blood tf, tf of stored blood. A few are normal due to aging of RBCs.

RBCs resemble stack of coins

Arrangement Rouleaux - Serum protein abnormality; e.g., ↑globulins or fibrinogen. Seen in multiple myeloma & macroglobulinemia. May be artifact due to delay in spreading drop of blood or smear that's too thick.

Agglutination

RBCs in irregular clumps - Autoantibodies, cold autoagglutinin.

Basophilic stippling

Aggregation of RNA (ribosomes) - Coarse: exposure to lead. Fine: young RBC.

Howell-Jolly bodies

Round, purple, 1-2 µm in diameter. Usually only 1 per cell - Usually pitted by spleen. Seen with accelerated or abnormal erythropoiesis.

Cabot rings

Reddish purple rings or figure-8s - Rapid blood regeneration, abnormal erythropoiesis.

Iron particles

Faulty iron utilization.

Pappenheimer bodies

Small purplish blue granules. Vary in size, shape, #. Usually in clusters at periphery - Sideroblastic anemias, postsplenectomy, thalassemia, sickle cell anemia, hemochromatosis.

Siderotic granules

Aggregates of iron particles - Blue granules of varying size & shape.

Reticulocytes

Blue-staining network - Residual RNA (ribosomes).

Heinz bodies

Precipitated, oxidized, denatured hemoglobin - Normal during aging but pitted by spleen.

Mean corpuscular volume (MCV)

Average volume of RBC - 80-100 fL.

MCV Calculation

MCV = HCT(%) × 10 / RBCs(10^6/L) - Used to classify anemias.

Normal MCV

Normocytic - MCV >100 = macrocytic. MCV <80 = microcytic.

Reticulocyte count

>2% = ↑ erythropoiesis; <0.1% = ↓ erythropoiesis.

Conditions for Howell-Jolly bodies

Postsplenectomy, thalassemia, hemolytic & megaloblastic anemias, sickle cell anemia.

Conditions for Pappenheimer bodies

Sideroblastic anemias, postsplenectomy, thalassemia, sickle cell anemia, hemochromatosis.

Conditions for Siderotic granules

Sideroblastic anemias, postsplenectomy, thalassemia, sickle cell anemia, hemochromatosis.

Normochromic

RBCs with normal MCHC; area of central pallor 1/3 diameter of cell.

Hypochromic

Cells with decreased MCHC; increased central pallor.

Hemoglobinopathy

Qualitative abnormality; abnormality in amino acid sequence of globin chain, not in amount of globin produced.

Thalassemia

Quantitative abnormality; normal amino acid sequence of globin chains but underproduction of 1 or more globin chains.

Sickle Cell Anemia (SS)

≥80% S, 1%-20% F, normal A2, no A; inheritance of sickle cell gene from both parents.

Sickle Cell Trait (AS)

No anemia; inheritance of sickle cell gene from 1 parent; occasional target cells.

Hemoglobin C Disease (CC)

Many target cells, folded cells, occasional Hgb C crystals; inheritance of gene for Hgb C from both parents.

Hemoglobin C Trait (AC)

Inheritance of gene for Hgb C from 1 parent; 60%-70% A, 30%-40% C.

SC Disease (SC)

Inheritance of 1 sickle cell gene & 1 Hgb C gene; >S than C, normal to 7% F, no A.

Hereditary Spherocytosis

MCHC usually >36 g/dL; ↑retics, ↑osmotic fragility; autoantibodies.

Autoimmune Hemolytic Anemia

Polychromasia, spherocytes, nRBCs; ↑retics, ↑indirect bili, ↓haptoglobin, pos DAT.

Megaloblastic Anemia

Pancytopenia, ↑LD; oval macrocytes, Howell-Jolly bodies, hypersegmentation, aniso, poik.

Folate Deficiency

Nutritional deficiency, ↑cell replication; deficiency impairs DNA synthesis.

Vitamin B12 Deficiency

Nutritional deficiency, malabsorption, impaired utilization; deficiency impairs DNA synthesis.

Nonmegaloblastic Anemia

Round macrocytes, no hypersegmentation; associated with alcoholism, liver disease, ↑erythropoiesis.

Iron Deficiency Anemia (IDA)

Most common anemia; insufficient iron for hgb synthesis; aniso, poik, hypochromic microcytes.

Sideroblastic Anemia

Enzymatic defect in heme synthesis; ringed sideroblasts in marrow.

Nucleated Red Blood Cells (nRBCs)

Immature red blood cells that still contain a nucleus, typically seen in severe anemia.

Ringed sideroblasts

Abnormal erythroblasts with iron-loaded mitochondria in the marrow.

Dual population of RBCs

Presence of both normocytic and microcytic red blood cells.

β-thalassemia major

Homozygous condition with little or no Hgb A, 95%-98% Hgb F, and 2%-5% Hgb A2, leading to severe anemia.

MCV in β-thalassemia major

Mean corpuscular volume less than 67 fL.

Marked aniso & poik

Presence of marked anisocytosis and poikilocytosis in red blood cells.

Hypochromic microcytes

Red blood cells that are smaller than normal and have reduced hemoglobin content.