Anaemia Flashcards
what is anaemia
reduced total red cell mass
is red cell mass easy to measure in routine practice
no
how is anaemia tested for
haematocrit and haemoglobin
where does red cell production take place
in the bone marrow
how would you recognise this
several erythroid precurosrs cluster around a central ‘nursing’ histiocyte
how do you measure haemoglobin concentration using a spectrophotometric method
burst-lyse the red cells to creat Hb solution
stabilise the Hb molecues (cyan-met Hb)
measure the optical density (OD) at 540nm
OD proportional to the concentration (Beer’s law)
Hb concentration calculated against known reference standard cyan-met Hb concentration solution
ow is haematocrit measure
ratio(or %) of the whole blood that is red cells if the sample was left to settle
modern machines calculate this by adding the calculated volume of the red cells it counts
when is Hb and haematocrit not a good measure
when there is acute blood loss and haemodilution occurs
what is the response to anaemia
increase red cell production-reticulocytosis
describe the appearance of retiuclocytes
larger than average red cells
still have remnants of RNA
stain purple/deeper red as a consequence
blood film appears polychromatic
what are the measured red cell indicies
haemoglobin concentration
number of red cells (concentration)
size of red cells (mean cell volume)
what are the calculated red cell indicies
haematocrit
mean cell haemoglobin
mean cell haemoglobin concentration
how is anaemia classified based on pathophysiology
decreased production( low reticulocytes) or increased loss or destruction of red cells (high reticulocyte count)
what are the cuases of low reticulocyte count
hypoproliferative-reduced amount of Erythropoeisis
maturation abnormality-erythropoiesis present but ineffective
what is high reticulocyte caused by
bleeding, haemolysis
what is a practical classification of anaemia based on
cell size and haemoglobin content
what is MCV a useful tool for
distinguishing between cytoplasmic and nuclear defects
if MCV low this means
microcytic-consider problems with haemoglobinisation
if MCV high
macrocytic-consider problems with maturation
where does haemoglobin synthesis occur
in cytoplasm
what does defects in haemoglobin synthesis cuase
small cells
describe microcytic anaemias
small red ells with a low hb content
hypochromatic and microcytic
hb synthesised in cytoplasm
to make Hb you need
globins
haem-porphyrin ring and iron
what are the causes of hypochromatic microcytic anaemias
haem deficiency-lack of iron for erythropoiesis-iron deficiency (low body iron), some cases of anamia of chronic disease (normal body iron but lack of available iron(
problems of porphyrin synthesis but this is vvv rare
globin deficiency-thalaslassameia
when fully saturated 1g hb will bind how much o2
1.34ml O2
