The Kleihauer is a semi quantitative test used to determine the concentration of fetal cells in an antenatal / postnatal patients sample. The method is based on the resistance of Fetal Haemoglobin (HbF) to acid elution. By use of Eosin counterstain fetal cells are stained and can be identified by light microscopy.
A Kleihauer is indicated in RhD negative patients with bleeds and sensitising events after 20 weeks gestation and post delivery, which should be sent with a cord blood sample to determine the newborns Rh(D) status.
In the event of a result suggesting a Fetal Maternal Haemorrhage (FMH)>4mls the sample will be referred to the National Blood Service for Flow Cytometry to determine the total volume of RhD positive cells.
An appropriate dose of Anti-D will be issued to cover the size of the FMH. For Antenatal bleeds please consult the Haematology SpR for advice.
Clinical details: 
For further information please refer to the GSTT Clinical Guidance Policy.
Reference range: 


Sample type and Volume required: 
Griener Vacutte K3EDTA 6 mls whole blood for adult tube (Pink top)
Griener Vacutte K2EDTA 4 mls whole blood for adult tube (Purple top)
Call in advance: 
Turnaround time: 
1 day (24 hours), however time critical tests can be performed within 2 hours – discuss with laboratory
Special sample instructions: 

Timing of samples - The maternal sample for FMH estimation should be taken when sufficient time has elapsed to allow fetal cells to be distributed within the maternal circulation following delivery, manual removal of placenta or sensitising event. A period of 30-45 minutes is considered adequate.                           

Other Factors Affecting Results: 

Hereditary Persistence of Fetal Haemoglobin (HPFH) and Delta-Beta -Thal. may give false positive results if assessing prophylactic Anti-D requirements. If this is the case, samples may be sent to NHSBT for Flow Cytometry. Patients with sickle cell disease or β-thalassemia are known to show poor elution of some of their red blood cells. This can affect interpretation of results.


Storage and transport: 
This test is time sensitive. Please send samples to the laboratory within an hour of collection. Samples >72 hours old cannot be tested. Sample retention: Samples are stored for 7 days.
Blood Transfusion Laboratory at Guy's and St Thomas' Hospital
020 7188 4774
Blood Transfusion Laboratory
St Thomas' Hospital
North Wing, 5th Floor
St Thomas' Hospital
Westminster Bridge Road
London SE1 7EH

Blood Transfusion Laboratory
Guy's Hospital
Southwark Wing, 4th Floor
Great Maze Pond
London SE1 9RT
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 16/05/2022