Hematology

• Hypovolemia

  Decreased blood volume caused by:

  ❑ Acute blood loss

  ❑ Plasma loss due (burns)

  ❑ Body water loss (dehydration


  Hypervolemia

  Increased blood volume caused by;

  ❑ Blood transfusion

  ❑ Intravenous infusion
• Platelet satellitosis


   The phenomenon of “platelet satellitosis” may occur when using EDTA.

   Platelets adhere around neutrophils, forming a ring of satellite effect.

   Using sodium citrate as an anticoagulant should correct this problem.
• Sodium Citrate


  : Binds calcium forming SOLUBLE complex (oxalate forms INSOLUBLE complexes)
• Oxalate


  MOA: Binds calcium to form INSOLUBLE calcium oxalate
• Heparin


  ✔ FOR OSMOTIC FRAGILITY TEST(OFT)

  ❑ MOA: promote the effect of antithrombin

  
  

  ◻ Increased OFT (decreased resistance)

  □ hemolytic anemias and hereditary spherocytosis and whenever spherocytes are found (AIHA, WAIHA)

  
  

  ◻ Decreased OFT (increased resistance)

  □ after splenectomy and in liver disease, sickle cell anemia, iron deficiency anemia, thalassemia and conditions where target cels are present
• Venipuncture Considerations


  ❑ Allow site to air dry after disinfection and before needle insertion.

  ❑ Angle of venipuncture: 15-30°

  ❑ Bevel position: BEVEL UP

  ❑ Tourniquet (18-20 inches): 3-4 inches (7.5-10cm) ABOVE the site for not more than 1 minute (CLSI)

  ❑ if more than one minute, RE-APPLYafter TWO mins

  ❑ BP cuff as tourniquet: 40-60 mmHg

  ❑ Always follow the recommended ORDER of DRAW

  ❑ Apply gauze or bandage and pressure to site after collection.

  □ DO NOT BEND THE ELBOWS
• Complications in Venipuncture

  ◻ Ecchymoses (most commonly encountered)

  ◻ Syncope (second most common)

  ◻ Hematoma

  ◻ Edema

  ◻ Thrombophlebitis

  ◻ Hyperventilation
• Stages of Hematopoiesis

  1. MESOBLASTIC/ YOLK SAC PHASE
  2. Hepatic Phase
  3. Medullary/ Myeloid Phase
• MESOBLASTIC/ YOLK SAC PHASE


  Begins around 19th day

  Formation of primitive erythroblast

  include Gower I (ez) , Gower II (ea) , and Portland (zega) types
• Hepatic Phase


  begins at 5th to 7th week of gestation

  liver becomes the major site of hematopoiesis
• Medullary (Myeloid) Phase


  ♥ By the end of 24 weeks of gestation, the bone marrow becomes the primary site of hematopoiesis.

  ♥ In adult hematopoiesis, the red marrow is found only in the:

  RSVP
• Erythrocyte Sedimentation Rate


  non-specific measurement used to detect and monitor an inflammatory response to injury (acute phase response)

  
  

  directly proportional to RBC mass and inversely proportional to plasma viscosity

  
  

  Stages of ESR

  1. Initial period of aggregation - lag/rouleaux phase

  2. Period of fast settling - rapid/ decantation phase

  3. Final period of packing - slow phase - 10mins
• ESR


  Increased - Inflammatory conditions, acute and chronic infections, rheumatic fever, rheumatic arthritis

  Decreased - Polycythemia, spherocytosis, sickle cells, sickle cell anemia
• ESR


  Westergren method is more sensitive of the methods, because of the longer tube it requires more blood

  ◻ Standard Westergren

  □ Westergren tube: Length 30 cm, bore 2.55 mm

  □ Uses citrate (black top) in a ratio of 1:4

  ◻ Modified Westergren

  □ Used EDTA instead of citrate

  WINTHROBE TUBE

  115 mm in length (shorter)

  100 mm graduations

  3 mm internal bore diameter
• Counting Methods

  Cross-sectional or Crenellation

  □ WBCs are counted in consecutive fields as the blood film is moved from side to side

  Longitudinal

  □ Indicated for thin smears

  Battlement method

  Most preferred counting method
• METHODS OF BLOOD FILM PREPARATION

  Cover glass smear (Ehrlich)

  Used for bone marrow samples

  Cover glass and slide (Beacom)

  ♥ Used for bone marrow samples

  Wedge smear

  Most convenient, and most commonly used method,

  Spun smear

  ♥ Buffy coat smear

  ♥ Thick blood smear
• Ideal Blood Smear


  □ No overlapping of cells

  □ Has a feathery edge

  □ With gradual transition from thick to thin

  □ Without scratches, holes, ridges
• Romanowsky stains


  □ Wright's, Giemsa, Modified Wright's-Giemsa, Leishman, Jenner and May-Grunwald

  ♥ For blood and Bone marrow staining: pH 6.8

  ♥ For Malarial parasites: pH of 7.2
• Platelet Count


  Reference range: □ 150,000-450,000/uL (conv)

  1. Direct - enumeration on counting chambers
  2. Indirect – enumeration on blood smears
• Reticulocyte Count


  ADULTS: 0.5 - 1.5 %

  Newborn: 2-6 %

  
  

  ♥ Reticulocytes are used to assess bone marrow functionality

  ♥ They are demonstrated primarily by a supravital stain (new methylene blue)
• Erythrocyte Indices


  MCV (Mean cell volume) -

  ▪ Reference range is 80-100 femtoliter

  ▪ Indicator of the average/ mean volume of RBCs.

  
  

  MCH (Mean corpuscular hemoglobin)

  ▪ Reference range is 26-32 picograms

  ▪ Indicator of the average weight of hemoglobin and RBC count

  
  

  MCHC (Mean cell hemoglobin concentration)

  ▪ Reference range is 32-36 g/dl

  ▪ Is the average concentration of hemoglobin in each individual cell

  
  

  RDW

  ▪ It is the fourth RBC index
• RULE OF THREE


   Used for checking the validity of test results
• HEMATOCRIT DETERMINATION


   It is also referred as Packed cell volume

   The PCV is used for detecting anemia, polycythemia, hemodilution, or hemoconcentration

  1.MACROHEMATOCRIT METHOD

   Winthrobe and Landsberg Double oxalate

  
  

  2. ADAM’S MICROHEMATOCRIT METHOD

  • Uses Capillary tube
• DONATH LANDSTEINER TEST FOR PCH

  ♥ The patient test specimen is incubated first at 4 C for 30 minutes and then at 37 C for 30 minutes
• TESTS FOR PAROXYSMAL NOCTURNAL HEMOGLOBINURIA

  Sugar water screening test

  Sucrose hemolysis test

  Ham’s Acid serum lysis test - CONFIRMATORY & DEFINITIVE TEST
• Platelet Structure

  1. PERIPHERAL ZONE - responsible for platelet adhesion and aggregation
  2. SOL-GEL / STRUCTURAL ZONE - comprise the platelet cytoskeleton
  3. ORGANELLE ZONE - composed of alpha and dense granules, mitochondria
  4. MEMBRANOUS SYSTEM - Dense tubular system (site of arachidonic acid metabolism) , Open canalicular system ( cannal for release of platelet granules )