Full Blood Count

Question 1

The full blood count analyse techniques

Answer 1

Spectrophotometry -

Question 2

Packed cell volume (PCV)

Answer 2

Proportion of blood that is made up of RBCs

Question 3

Haemoglobin

Answer 3

Reference ranges vary between labs but generally
	>135g/L adult men
	> 115g/L adult women
	>110g/L children (3/12 – puberty)
	>150g/L newborns

Question 4

RBC cell count (RCC)

Answer 4

Number of RBC in given volume of blood (single cell column of blood passing through a detector)

Question 5

Mean cell volume

Answer 5

Mean size of RBC, measured using the amount of light scattered as they pass in a single file past a laser.

The most important parameter used to screen the cause of anaemia

Mean cell Hb - Average measure of the amount of Hb in each RBC (e.g. Hb/RCC)
Used in assessment of anaemia
Usually reduced in iron deficiency but normal or increased in macrocytic anaemias

Mean cell Hb concentration (MCHC) - Mean concentration of Hb in RBC (Hb/MCV x RCC)
One of least useful parameters: however increased if spherocytosis.
Most useful in laboratory in the identification of cold agglutinins (e.g. viral/ mycoplasma infections etc.)

Question 6

Red cell width distribution

Answer 6

Variation in size of the RBC
If increased = anisocytosis
Used to help assess cause of anaemia
Increased in iron deficiency (the first parameter to rise as iron stores fall)

Question 7

Reticulocyte count

Answer 7

Measurement of the number of young erythrocytes

Question 8

Blood film

Answer 8

This occurs when a sample is ‘flagged’ as requiring a blood film:

Occurs when -

• Significant result outside of the normal range
• Significant change within the normal range
• Analyser thinks there are abnormal cells i.e. Immature cells or cells

Question 9

RBC terminology

Answer 9

Microcytic - small
Macrocytic - large
Hypochromic - pale (less Hb)
Hyperchromic - Dense (more Hb than normal)

Anisocytosis - increased variability in size
Dimorphism - 2 district populations of red cells (due to transfusion)
Poikilocytosis - abnormally shaped RBC
Spherocytosis - spherical RBC
Eliptocytosis - elliptical RBC
Sickle cells - crescent shaped cells seen in sickle cell disease
Target cells - RBC with dark area in the middle of the area of central pallor

Question 10

Inclusions in Erythrocytes

Answer 10

Howell-Jolly bodies - DNA/nuclear fragments
Basophils stippling - RNA inclusions in cells
Pappenheimer bodies - Iron inclusions in cells
Heinz bodies - denatured haemoglobin

Question 11

WBCs

Answer 11

Increased for numerous reasons

5 part differential - Neutrophuls, Eosinophils, Basophils, Lymphocytes, Monocytes

NRBC can be counted as white cells by analyser

Question 12

Platelets

Answer 12

Most frequent aberrant parameter
Very reactive cells
Infection/ inflammation could go very high or low
Iron deficiency, could go high or low
Drugs - can vary number
If any clots in the sample then the plate and the count will be reduced
Platelet clumping