agile - affordable - accurate. hematology, is the part of internal medicine, that is concerned with...

agile - affordable - accurate


• Hematology, is the part of internal medicine, that is concerned with the study of blood, the blood-forming organs, and blood diseases.

• The bunch of methods for counting, measuring and evaluating blood cells suspended in fluid is known as Hematology Cellcounting.

• A blood cell analyzer, is used to perform one of medicine's most often-requested and informative diagnostic tests, the complete blood count (CBC).

Hematology Cellcounting - Basics


Blood is a specialized fluid, „liquid tissue”, that circulates around the body in blood vessels.

It’s main functions:

- Transport through the body of

– oxygen and carbon dioxide

– nutrient molecules, ions, hormones

– „wastes”

– Heat

- Defense of the body against infections, injuries and other foreign materials.

Blood


Composition of blood

Liquid Plasma: over 90% of plasma is water, it also contains proteins, salts, metabolits etc. After centrifuging it is called serum.

Cells: Erythrocytes(Red Blood Cells, RBC)

Leukocytes(White Blood Cells, WBC)

Thrombocytes(Platelets, PLT)

Erythrocytes The most numerous and common type of blood cells. Non nucleated in mammals, with biconcave shape, erythrocytes are responsible for the transport of oxygen. Contain hemoglobin(HGB), iron, and structures on the cell membrane determine blood

group systems.


Reticulocytes: immature blood cell forms, contain remnants of the nucleus(ribosomal RNA). Present normally in a

very few% of the total RBC number.

Hemoglobin: red blood cells contain several hundred HGB molecules which:

transport oxygen(main function)

contain iron

cause the red colour of blood

Erythrocytes – cont’d


Thrombocytes and other parameters

Thrombocytes: thrombocytes or platelets play an important role in the cellular part of the hemostazis(coagulation) trying to prevent excessive blood loss. Non nucleated cells in mammals and the smallest ones in the same time. Contain specific granules.

Hematocrit – HCT or Packed Cell Volume – PCV: Shows the volume of blood in % occupied by cells.It can be measured after separation in a centrifuge, or calculated after cell counting. Shows the degree of anemia.

Mean Corpuscular Volume – MCV: Average volume of individual erythrocytes

Mean Corpuscular Hemoglobin – MCH: Average hemoglobin content of erythrocytes, calculated from RBC and HGB values. MCH = HGB / RBC


Other parameters

Mean Corpuscular Haemoglobin Concentration – MCHC:

Calculated from the HGB and HCT values. MCHC = HGB / HCTabsolute

Red cell Distribut. Width - RDW-SD

Platelet Distribut. Width - PDW-SD

and

Red cell Distribut. Width - RDW-CV

Platelet Distribut. Width - PDW-CV

The distribution width of the erythrocyte or platelet population derived from the histogram at 20% of peak


Mean Platelet Volume – MPV: Average volume of individual platelets derived from the PLT histogram.

Thrombocrit – PCT: Calculated from the PLT and MPV values.

PCTpercentage = PLT x MPV x 100; PCTabsolute = PLT x

MPV

Hemolysis: rupture of the cell membrane followed by destruction of the cell. When RBC-s are

lysed hemoglobin is released.

Hemolytic agents: detergents, PH, osmotic pressure, drugs, immunsystem, diseases etc.


Leukocytes - WBC

White blood cells are a very important part of the immune system defending the body against infectious diseases and foreign materials.

By complexity of the internal structure :

- Granulocytes (complex nucleus, granules in the cytoplasm)

- Agranulocytes (simple nucleus, non granulated)

By cell size:

- „Small”- „Medium”- „Big” cells

There are 5 main WBC populations: (see next page… )


Leukocytes – cont’d

Monocytes: mononuclear cells with oval, nucleus and variable

cytoplasm (vacuoles)

Neutrophils granulocytes: polimorphonuclear cells with neutral

cytoplasm & granules

Eosinophil granulocytes: polimorphonuclear cells with basic

(alkaline) cytoplasm & granules

Basophil granulocyte: polimorphonuclear cell with acid cytoplasm &

granules

Lymphocytes: mononuclear cell with round, dense nucleus and

slight cytoplasm


Types of blood cells


Measurement principles

Name RBC WBC PLT

Population 4.5-5.5 million/µl 5-10.000/µl 150-300.000/µl

Shape, diameter

Biconcave shape

Diameter 8 µm

Thickness 2 µm

NE,EO,BA 15 µm

LYM 8-15 µm

MON 15-25 µm

Fragments

Diameter 2-4 µm

Mean volume

90 fl various 12 fl



Blood sample: whole blood mixed with EDTA, anticoagulants are necessary to prevent forming of clots



1.

Blood

3. Hemolyser

WBC & HGB1:200

2.

RBC & PLT1:32.000

Sample preparation: from the whole blood a small amount (20-25ul) of primary sample is aspirated.

Diluent is added to the sample first (WBC&HGB) dilution is obtained

From this first dilution a second sample(100ul) is aspirated

Diluent is added to the second sampleRBC&PLT dilution is obtained

Lyse reagent is added to the WBC&HGB dilution RBCs are destroyed (see next slide)

1. a + diluent → b2. b + diluent → c → RBC/PLT3. b + Lyser → WBC/HGB

a b c


WBC differential Lysing process

PLT & RBC LYM MON GRA

RBCs destroyed

WBCs selectively shrank to nuclei


Impedance cell counting principle


3-part Differential WBC Histogram

& HGB


Hemoglobin measurement principle

agile - affordable - accurate. hematology, is the part of internal medicine, that is concerned with...

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