Session 3- Interpreting the Full Blood Count Flashcards
(27 cards)
errors in specimen collection
specimen mix up WBIT wrong bottle pooling samples poor technique
errors in delivery of specimen
specimen delayed/ not delivered
wrong delivery method
errors in specimen analysis and result
specimen mix up incorrect clinical details wrong test requested/ performed inherent test variability technical error
errors in responsive action
result nor reviewed
reflex tests not carried out
right result applied to wrong patient
spectrophotometry
amount of light absorbed by sample proportional to amount of absorbed compound within it
-used to measure amount of haemoglobin
flow cytometry
hydrodynamic focussing
- single file line of cells
- pass through light beam
impedance counting
forward scatter= size
side scatter= mono/polymorphonuclear
more scatter = bigger cell
Packed cell volume
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
RCC
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
MCV
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
MCH
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
RDW
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
reticulocyte count
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
microcytic
small RBC
Macrocytic
large RBC
Hypochromic
MCH pale less Hb
hyperchromic
MCH dense more Hb in given volume
anisocytosis
increased variability in size
dimorphism
two distinct populations of red cells
poikilocytosis
abnormally shaped RBC
spherocytosis
spherical RBC
eliptocytosis
elliptoid RBC
irregularly contracted cells
small dense RBC but not as regular in shape as spherocytes
echinocytes, acanocytes, keratocytes, schistocytes
spiculated cells
sickle cells
crescent or sickle shaped cells seen in sickle cell disease
