Introduction to Blood

Question 1

What is used as an anticoagulant for blood screens?

Answer 1

EDTA, which binds to calcium ions preventing clotting

Question 2

Why is MCHC not often reported?

Answer 2

Highly inaccurate as combining all three values (Hb, MCV and MCH) gives little information.

Question 3

What is RDW?

Answer 3

Variability in red cell width, if high signals disorder of erythropoiesis.

Question 4

Name the following anaemia:

a) MCV + MCH down
b) MCV and MCH normal
c) MCV increased

Answer 4

a) microcytic hypochromic
b) normocytic normochromic
c) macrocytic

Question 5

Which patient parameters affect the reference ranges for blood screens?

Answer 5

sex and age (e.g. adult female vs infant male)

95% will fit into this, 5% lie outside and this is normal!

Question 6

Haemopoietic stem cells in bone marrow divide into…..

Answer 6

Mixed myeloid progenitor stem cell AND lymphoid stem cells

Question 7

What cells does the myeloid stem cells form?

Answer 7

Erythroblasts, (megakarocytes)Platelets, Granulocytes, Monocytes, Dendritic cells

Question 8

Which cells are produced via the lymphoid lineage?

Answer 8

B cells, T cells, NK cells and dendritic cells

Question 9

What controls the growth of haemopoietic stem cells?

Answer 9

Mesenchymal stem cells, growth factors (Stem cell factor - 1, FLT-ligand)

Later on IL-3, EPO, TPO and G-CSF

Question 10

What do the following control:
- EPO
- TPO
- G-CSF

Answer 10

Erythropoiesis for RBCs
Thrombopoiestin for platelets
G-CSF is for neutrophils

Question 11

What are reticulocytes and how do they appear?

Answer 11

Immature RBCs, their remnants of organelles + RNA stain blue causing a blue ‘reticulated’ pattern.

Question 12

What does a high % of reticulocytes point to?

Answer 12

Haemolysis (shortened RBC, reticulocyte % will increase)