Blood Testing 1

8/14/2019 Blood Testing 1

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Blood Testing


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Objectives:

Define blood testing Significance of blood testing

What is CBC?

Normal Ranges

Direct measurements

Indirect measurements

Anemias

Classification

Brief description


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Blood Testing

Blood Sample

Complete Blood Count (CBC) WBCs (4000-10800 cells/mm3 )

Plateltes (150,000-400,000 cells/mm3)

RBCs (Male: 4.65.9, Female: 4.25.4 million cells/mm3 )

Direct measurements RCC (Red cells Count)

Hb Concentration (g/dl)

Hematocrit (Hct) (Vol of RBCs / Vol of whole blood)

Calculated from direct measurements MCH (Mean Corpuscular Hb Mass / RBC)

MCV (Mean Corpuscular volume/RBC)

MCHC (Mean Corpuscular Hb Conc. per Liter (RBC)
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Blood Testing
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Anemias

Diagnostic Classification

1. Kinetic Approach Production vs. destruction or loss

Reticulocyte Production Index (RPI)

2. Morphological Approach Red blood cell size

Microcytic (Cells Smaller than normal size i.e. MCV< 80 fl)

Normocytic (Cells Normal sized i.e. MCV = 80-100 fl)

Macrocytic (Cells bigger than normal size i.e. > 100 fl)

Concentration of Hb Hyperchromic (Increased Hb Concentration)

Normochromic (Normal Hb Concentration)

Hypochromic (Decreased Hb Concentration- cells palerthan normal)


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Anemia Anemia means deficiency of hemoglobin in the blood

Cause Too few red blood cells or Too little hemoglobin in the cells.

Classification

1. Aplastic or Hypoplastic Anemia

2. Nutritional Anemia

3. Hemolytic Anemia

Aplastic or Hypoplastic Anemia Aplastic Loss of bone marrow function Hypoplastic Reduced bone marrow function

Anemia due to lack of functioning of Bone Marrow or bonemarrow aplasia. Aplastic anemia patients have lower counts of all

three blood cell types: termedpancytopenia. Characterstics:

Decreased Red blood cells

Diminished immunity Tendency to bleed


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Aplastic Anemia

Causes

Drugs e.g. (Cytotoxic drugs, some anti convulscent drugs etc)

Radiations (X-Rays)

Chemicals (Benzene and its derivatives)

Viral diseases

Invasion of bone marrow (fibrosis or Leukemia)

Hereditary Congenital hypoplastic anemia (or constitutional aplastic anemia) a

type of aplastic anemia which is primarily due to a congenitaldisorder(defects or damage to a developing fetus). Examples include:

Fanconi anemia (Caused by short Stature, Skeletal Abnormalities) Diamond-Blackfan anemia (Congenital Erythroid Aplasia- Characterized by anemia

with decreased erythroid progenitors in bone marrow)

Acquired Pure Red cell Aplasia (PRCA)

Sideroblastic anemia (Sideroachrestic anemia)1 The body has iron available, butcannot incorporate it into hemoglobin

Myelophthisic anemia2 (Normal marrow space is replaced by nonhematopoietic orabnormal cells). Cause e.g. tumors


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Nutritional Anemia

1. Nutritional Anemia Type of anemia that can be directly attributed to nutritional

disorders Iron Deficiency Anemia (Microcytic) Megaloblastic Anemia (Macrocytic)

Iron Deficiency Anemia (Microcytic) Sideropenic Anemia, cells are smaller in size and paler in colour

Causes: Parasitic Infections

e.g. Hook worms Normal Requirement, Deficient intake

Weight reducing diets, Vegetarian diets High Requirements, Normal or deficient intake

Pregnancy Chronic blood loss (peptic ulcers, menorrhagia,

haemorrhoids, GI carcinoma) Low iron absorption or malabsorption

GI abnormalities Increase in pH (removal of part of stomach)

Loss of absorbing surface area (intestine removal)


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Nutritional Anemia

Megaloblastic Anemia (Macrocytic) Inhibition of DNA synthesis during erythropoiesis

Large, immature RBCs (Megaloblasts)

Characterstics: Immature, fragile cells,

Life span b/w 40-50 days

Size larger than normal cells,

Might contain nucleus

Causes: Hypovitminosis (B12, B9)

Antimetabolites that inhibit DNA synthesis e.g.

Purine & Pyrimidine Antagonists (6-Mercaptopurine,

Cytosine)


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Nutritional Anemia Vitamin B12 deficiency Anemias

Deficient intake in diet (vegetarians)

Deficient intrinsic factor (Gestractomy & Pernicious Anemia) Selective B-12 malabsorption (removal of Terminal ileum) Increased needs: pregnancy, infant, rapid cellular proliferation.

Pernicious Anemia Most common form of Vitamin B12 deficiency Anemias Occurs more often in females

Cause: Autoimmune disease results in production of antibodies

directed against Intrinsic Factor (IF)*andparietal cells instomach.

Impaired absorption of vitamin B-12 due to the absence ofintrinsic factor as a result of loss of gastric parietal cells.

Treatment IV injections of Vitamin B-12

Complications of B-12 deficiency anemia Appear before the signs of anemia Includes Irreversible neurological damage commonly in spinal

cord (B-12 needed for formation and maintenance of Myelin byschwann cells)


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Nutritional Anemia

Vitamin B9 (Folic Acid) deficiency Anemias

Deficiency causes megaloblastic anemia but notassociated with neurological damage

Causes Dietary Deficiency e.g. in infants absence or delay of

establishing mix diets. Alcoholism Anorexia (Loss of appetite) Pregnancy (Raised requirement)

Malabsorption from jejunum (tropical sprue) Interference with Folate metabolism

Folic acid Antagonists (Methotrexate)

Trimethoprim (Antimicrobial agent)

Deficiency Causes neural tube defects duringpregnancy*


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Folic acid Metabolism


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Hemolytic Anemias

1. Hemolytic Anemias

Occur when RBCs are destroyed in circulation or removedprematurely from circulation because of abnormal cells oroveractive spleen

Hereditary or Congenital hemolytic AnemiasHereditary or Congenital hemolytic Anemias Hemolytic anemia which is primarily due to congenital

disorders Types include:

Genetic conditions of RBC Membrane Hereditary spherocytosis (Sphere shaped RBCs)

Hereditary elliptocytosis (Elliptical RBCs) (Also known as ovalocytosis)

Genetic conditions of RBC metabolism (enzyme defects) Glucose-6-phosphate dehydrogenase deficiency (G-6-PD)

Pyruvate kinase deficiency (No energy)

Hemoglobinopathies / genetic conditions of hemoglobin Sickle cell anemia

Thalassaemia


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Hemolytic Anemias

Acquired hemolytic anemia

No familial or racial factors have been identified Causes:

Chemical Agents: These agents may cause excessive or early hemolysis

Some Drugs, if taken for long time & in large doses e.g.

Sulphonamides

Chemicals faced in general or work environment e.g.

lead, arsenic compounds

Toxins produced by certain microbes.

e.g. streptococcus pyogenes

Autoimmunity Production of antibodies against self antigens

Blood transfusion Reactions Parasitic Disease e.g. malaria

Physical damage to cells by e.g. artificial heart valves, dialysismachines.

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Blood Testing 1