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July 2023 Exam
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Demo Question
A 36-year-old woman is found to be rhesus status negative and has recently delivered. She has a Kleihauer test performed.
What is the principle of Kleihauer test?
HbF is more resistant to acid than maternal red cells
Hbf has higher affinity for oxygen than maternal haemoglobin
HbF is resistant to cold
Hb F is larger in quantity
Maternal haemoglobin is more resistant to acid than Hb F
Key Learning Point
Rhesus negative mothers are offered anti D immunoglobulins to prevent complications in subsequent pregnancies.
Explanation
This test is to confirm transplacental blood loss. The test is performed on the mother's blood.
HbF more resistant to acid elution than the maternal cells. The fetal cells, therefore, stain red, maternal cells stain pink staining.
Fetal red cells contain HbF and are therefore more resistant to acid elution than the maternal cells. The fetal cells therefore stain red, maternal cells stain pink.
