Session 3- Interpreting the Full Blood Count

Question 1

errors in specimen collection

Answer 1

specimen mix up 
WBIT 
wrong bottle 
pooling samples
poor technique

Question 2

errors in delivery of specimen

Answer 2

specimen delayed/ not delivered

wrong delivery method

Question 3

errors in specimen analysis and result

Answer 3

specimen mix up
incorrect clinical details
wrong test requested/ performed
inherent test variability 
technical error

Question 4

errors in responsive action

Answer 4

result nor reviewed
reflex tests not carried out
right result applied to wrong patient

Question 5

spectrophotometry

Answer 5

amount of light absorbed by sample proportional to amount of absorbed compound within it
-used to measure amount of haemoglobin

Question 6

flow cytometry

Answer 6

hydrodynamic focussing

• single file line of cells
• pass through light beam

impedance counting
forward scatter= size
side scatter= mono/polymorphonuclear
more scatter = bigger cell

Question 7

Packed cell volume

Answer 7

proportion of blood that is made up of RBC
-centrifuged blood allows visualisaion

used to asses anaemia but more often polycythemia

• diagnosis and treatment
• the PCV/Hct is reduced in polycythemia either by venesection or drug treatment

Question 8

RCC

Answer 8

Red cell count
-number of RBC in given volume of blood

used for assesment of anaemia and erythrocytosis

• microcytic anaemia
  
  • reduced in iron deficiency anaemia
  • increased in thalassemia trait
• erythrocytosis: if RCC elevated, more likely to be atrue polycythaemia
  
  • spurious polycythaemia caused by decreased plasma volume, RCC wont be increased

Question 9

MCV

Answer 9

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

most important parameter used to screen the cause of anaemia

Question 10

MCH

Answer 10

mean cell haemoglobin
-average measure of the amount of Hb in each RBC

used in assesment of anaemia

usually

• reduced in iron deficiency
• normal or increased in macrocytic anaemia
• increased if sphericytosis

Question 11

RDW

Answer 11

red cell distribution width

if increased- anisocytosis

used to help assess cause of anaemia

• increased in iron deficiency
• usually normal in thalassaemia trait
• increased following trasnfusion

Question 12

reticulocyte count

Answer 12

measurement of the number of young erythrocytes
identified using size and RNA content

increased in

• haemolytic anaemia
• recent blood loss
• response in iron, Vit B12, folate replacement
• response to EPO
• Recovery from bone marrow suppression

reduced in

• haematinic deficiency
• bone marrow failure

Question 13

microcytic

Answer 13

small RBC

Question 14

Macrocytic

Answer 14

large RBC

Question 15

Hypochromic

Answer 15

MCH pale less Hb

Question 16

hyperchromic

Answer 16

MCH dense more Hb in given volume

Question 17

anisocytosis

Answer 17

increased variability in size

Question 18

dimorphism

Answer 18

two distinct populations of red cells

Question 19

poikilocytosis

Answer 19

abnormally shaped RBC

Question 20

spherocytosis

Answer 20

spherical RBC

Question 21

eliptocytosis

Answer 21

elliptoid RBC

Question 22

irregularly contracted cells

Answer 22

small dense RBC but not as regular in shape as spherocytes

Question 23

echinocytes, acanocytes, keratocytes, schistocytes

Answer 23

spiculated cells

Question 24

sickle cells

Answer 24

crescent or sickle shaped cells seen in sickle cell disease

Question 25

target cells

Answer 25

RBC with dark area in the middle of the area of central pallor

Question 26

basophillic stippling

Answer 26

RNA inclusions in cells

Question 27

Pappenheimer bodies

Answer 27

iron inclusions in cells