Kleihauer Test

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Also known as the Kleihauer-Betke Test, it is used to assess foetomaternal haemorrhage.

The Kleihauer test allows detection and quantification of foetal blood within the mother's circulation, ie. foetomaternal haemorrhage.

The test is also regularly performed on Rhesus negative pregnant women to determine the dose of anti-D (rhesus immunoglobulin) required to be given to the mother to prevent formation of rhesus antibodies and rhesus disease in any future rhesus positive children.

Image 1: Kleihauer Betke Stain, massive foetomaternal haemorrhage

Indications for a Kleihauer Test

  • Suspected foetomaternal haemorrhage
  • Rhesus negative mother to allow anti-D dose determination
  • Abdominal trauma during pregnancy
  • Stillbirth assessment
  • Following external cephalic version (ECV)

Laboratory Method

A blood sample is taken from the mother and a standard blood film prepared.

This is then exposed to acid, which denatures adult haemoglobin (two alpha and two beta subunit chains). However, foetal haemoglobin contains two alpha and two gamma subunits: this combination is not susceptible to being denatured by acid. A stain is then added to the slide, resulting in foetal red cells appearing pink under a microscope whilst adult cells appear pale (see Image 1).

The number of foetal red cells are counted and compared to the number of adult red cells.

  • False positive results can occur where the mother has higher levels of foetal haemoglobin, HbF, for example in Sickle Cell Trait.
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