Summary BHCS2005 Clinical Haematology and Biochemistry - Methods in Haematology

Methods In Haematology

Full Blood Count
 Automated analysers detect
o Number and size of RBCs, WBCs and platelets

o Haemoglobin concentration

o Haematocrit



Values
 Red cell count
o Male - 4.5-6.5 x 10^12/L

o Female - 3.9-5.6 x 10^12/L

 Haemoglobin
o Male - 13.5-18 g/dL

o Female - 11.5-16 g/dL

 White cell count




Haematocrit
 Haematocrit is the packed cell volume
o 40-52% in males

o 38-48% in females

 Mean corpuscular haemoglobin
o The amount of oxygen carrying haemoglobin inside RBCs

 Mean corpuscular haemoglobin concentration
o Concentration of haemoglobin per RBC

 Red cell distribution width
o Variation in size of RBCs



Inflammatory Tests
 Erythrocyte Sedimentation Rate

, o Non-specific test for inflammation

o Increased fibrinogen with inflammation makes RBCs sticky and
sediment faster
o Inexpensive, quick and simple

o Affected by a variety of factors

 C-reactive protein
o Acute inflammatory response

o Most rapid response

o Wide reference

o Expensive



Blood Smear
 Performed manually to detect size, number and type of cells
 Additional test to ESR
 Giemsa stain used to detect morphology of granulocytes and platelets


Automated Analysers
 Spectrophotometry
o Measures haemoglobin concentration by converting to
cyanmethemoglobin and measuring absorbance at 540nm
 Impedance
o Measures cell size and number for RBC, WBC, platelets and mean
cell volume
 Flow cytometric analysers
o Detect cell shape, size, granularity and epitopes

o Individual cells are passed through a laser beam

o Forward scatter for size, side scatter for complexity

o Automatic count cells within known regions

 Flow cytometry gating
o One parameter

 Cell count and measurement of fluorescence
o Two parameter