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Interpreting the CBC

Robert Miller PAAssistant Professor of Clinical Pediatrics and

Family Medicine

USC Keck School of Medicine

Retired

The CBC

3 Cell Lines

• Assess general health

• Make a diagnosis

• Monitor a diagnosis

• Monitor treatment

RBCs

WBCs

Platelets

Normal RBCs

RBC “Morphology”

Red Cell Line (Adult values, Medscape)

• RBC 4.7-6.1 M cells/mcl (M), 4.2-5.4 (F)

• Hgb 13-17 g/dL (M), 12-15 (F)

• Hct 40%-52% (M), 36%-47% (F)

• MCV 80-100 fL

• MCH 27-31 pg/ml

• MCHC 30-35 g/dL

• Reticulocyte 0.5-1.5%

• RDW 11.5-14.5%

RBC Morphology

AnisocytosisPoikliocytosis

Microcytosis

Macrocytosis

Hypochromasia

Polychromasia

Spherocytosis

Target cells

Schistocytes

Fragmented cells

Sickle cells

RBC Morphology

• Anisocytosis: excess variation in size

(High RDW, iron def., many others)

• Poikilocytosis: excess variation in shape

(Hemolytic disorders, nutritional def., others)

RBC Morphology

• Microcytosis: small cells (MCV < 80)

(Iron def., hemoglobinopathy, chronic disease)

• Macrocytosis: large cells (MCV > 100)

(Megaloblastic, alcohol, liver dis., retics)

RBC Morphology

RBC Morphology

• Hypochromasia: pale cells

(Iron def., anemia of chronic dis., others)

• Polychromasia: blue tinge to cytoplasm –indicating a young cell (young reticulocyte)

RBC Morphology

Iron Deficiency Anemia

RBC Morphology

Associated With Hemolysis

Spherocytes: spherical cells

Target cells: target appearance with hemoglobin concentration in center

Sickle cells: crescent shape

RBC Morphology

Target Cells & Spherocytes in

Hemoglobinopathy

Sickled Cells

RBC Morphology

Schistocytes: fragmented cells

(DIC, MAHA, TTP, HUS, cardiac valves, etc)

Howell-Jolly body: blue spot of DNA remnants

(Asplenic, hyposplenism)

Agglutination: RBC clumping

(Antibodies - usually IgM, mycoplasma, mono)

Copyright © 2013 American Society of Hematology. Copyright restrictions may apply.

Peter Maslak, ASH Image Bank 2013; 2013-3718

Schistocytes

Howell – Jolly Body

• Howell-Jolly body

No Spleen ?

• Nucleated RBC

Why ?

Cold Agglutinin / Agglutination

RBC Morphology

RBC - Reticulocytes

• Immature cells characterized by a network of filaments and granules



Nucleated red blood cell

Reticulocytes

Young RBCs, N = 1 % (.5 - 1.5)

Index of erythropoetic activity

Increased following : treatment of anemia

blood loss

hemolysis

Retic % X Pt. Hct. = “corrected retic”

normal (45)

6 % X 30 = 4 %

45

12 % X 15 = 4 %

45

Corrected Retic For Degree of Anemia

Double Correction for Retic ?

“Reticulocyte production index (RPI)”

• First correct for degree of anemia

• A second correction graph is for the degree of prematurely released reticulocytes. Slide will show polychromasia (polychromatophilicmacrocytes)

RBC Morphology - RPI

• Hematocrit (%) Retic maturation correction

• 36-45 1.0

• 26-35 1.5

• 16-25 2.0

• 15 and below 2.5

6 % X 30 = 4 %

45

1.5 = 2.7%

RBC Morphology

The Indices

• MCV: mean cell volume (80 – 100 fL)

• MCH: mean cell hemoglobin

• MCHC: mean cell hgb concentration

Anemias: Think About The Retic

• If caused by a nutritional deficiency (like iron / B12 / folate) will probably have a low retic … until the nutrient is provided to increase RBC production

• If caused by RBC loss (bleeding or hemolysis) will probably have a high retic “compensating” for the low hgb/hct … because it has the nutrients & ability to increase RBC production

Hemolytic Anemia

Hgb / Hct ↓ (low or falling)

Retic ↑ (increased)

? RBC loss = bleeding / hemolysis

? Recent Rx for anemia

Anemia... Diagnosis

1) The patient has an anemia and RBCs are:

Microcytic Normocytic Macrocytic

2) The retic count is higher or lower than expected

High - blood loss / hemolysis ?

Low - nutritional deficiency ?

RBC Size – Common Anemias

Microcytic Normocytic Macrocytic

Iron deficiency Bleeding (acute) Megaloblastic

Thalassemia Hemolysis Alcoholism

(Lead) Aplastic anemia Medications

Liver desease

Anemia of Anemia of

chronic disease chronic disease

Reproduced with permission from: Rao AK. Am J Med Sci.

1998;316:69–76.

A representation of normal platelet responses and the congenital disorders of platelet function

Bernard Soulier Syndrome

vWD Glanzmann’’’’s Thrombasthenia

Deficiency of Platelet Coagulant Activities

Fibrinogen

GP IIb/III

a

Afibrinogenemia

Platelets ... Evaluation

Number

Morphology

Function

Platelet

Production

Thrombopoietinstimulates platelet production

Megakaryocyte stays in the marrow

Platelet development, by OpenStax College

Platelet ... Evaluation

CBC

• Platelet count (150 – 450K)

• Mean platelet volume (MPV)

• Morphology (uncommon)



Platelets.

Platelet Morphology

• Mean platelet volume (MPV)

(normal MPV 7.5 – 11.5 fL

• Large platelets

• Giant platelets

• Defective granulation

(grey platelet syndrome0



Giant platelet.

RBC, Platelet, Leukocyte

Electron micrograph facility, NCI at Fredrick

Platelets

Platelet size can be of diagnostic significance when associated with thrombocytopenia …

Thrombocytopenia caused by bone marrow failure may have a low or normal MCV

Thrombocytopenia caused by peripheral destruction

(eg. ITP) usually have higher MCV

Platelets

Peripheral destruction of platelets (like in ITP) is associated with a higher MPV because the increased production of new, young platelets are typically a little larger and more active

This possibly explains how many patients do OK with even very low platelet counts

TWBC & Differential

• Total leukocytes: 4.0 - 11.0 x 10 9/L

• Neutrophils: 40 – 80 %

• Lymphocytes: 20 – 40 %

• Monocytes: 2 – 10 %

• Eosinophils: 1 – 6 %

• Basophils: 1 – 2 %

Macrocytes / Hypersgmented Poly

Lymphoblast

Normal Bone Marrow

Atypical Lymphocytes

Neutropenic Disorders

Quantitative Disorders

• Accelerated Destruction

• Maldestribution

• Decreased Production

Neutropenia

Neutropenia: Absolute Neutophil

Count

ANC <1500 cell/mm3

Severe Neutropenia: ANC < 500 cells/mm3

Severe Neutropenia

Studies have shown:

Severe neutropenia (ANC < 500) may

result with 40% of patients developing

“febrile neutropenia” within a 4 day period

Absolute Neutrophil Count (ANC)

ANC calculation Total WBC x % Total Neutrophils

Example: Total WBC = 5000/mm3

Band Neutrophils = 5%

Segmented Neutrophils = 55%_________________________________________________

ANC = 5,000 x 60% = 3,000

Captain Morgan

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