Red cells Flashcards
What are the 5 main genes involved in HS?
ANK1
SLC4A
SPTA/B
EBP4
What is hereditary spherocytosis (HS)?
An inherited red cell membrane disorder that results in red cells losing their biconcave shape and increased susceptibility to haemolysis via splenic destruction.
What abnormalities might be found in a complete blood examination (CBE) for HS?
Anaemia, normal MCV, elevated MCHC.
What are the characteristic findings on a blood film for hereditary spherocytosis?
Spherocytic red cells and possible polychromasia.
What is an important differential diagnosis for hereditary spherocytosis?
Immune Haemolytic disorders (AIHA).
What is the red cell osmotic fragility test used for in the context of HS?
To assess red cells’ vulnerability to haemolysis in hypotonic solution.
What is the sensitivity of the red cell osmotic fragility test?
Approximately 75%.
What is the gold standard diagnostic test for hereditary spherocytosis?
Flow cytometry for Eosin5’Malemide.
How does Eosin5’Malemide work in diagnosing HS?
It binds to band 3 protein on normal red cell membranes, which is deficient in HS, leading to decreased fluorescence.
What is the sensitivity and specificity of the Eosin5’Malemide test?
> 90% sensitivity/specificity.
When might molecular genetic testing be useful in hereditary spherocytosis?
- Complex diagnostic cases
- Prenatal diagnosis
- Genetic counselling.
What additional tests may be performed in suspected HS?
- Iron studies
- Folic acid levels
- Liver function studies
- Abdominal ultrasound.
Why are iron studies important in cases of chronic haemolysis?
To assess for deficiency or overload due to transfusion history.
What conditions are commonly associated with abdominal ultrasound findings in HS?
- Splenomegaly
- Cholelithiasis.
