Fetal Red Cell Detection Kit (Kleihauer Test)
Background information
Click here to return to the Guest Medical Kleihauer Test kit.
Background to Haemolytic Disease of the Newborn
Haemolytic disease of the newborn (HDN) occurs when antibodies from the mother's
blood attack the child in utero. The antibodies causing the problem will have
been formed as a result of an earlier pregnancy when, usually during the trauma
of childbirth, some of the baby's blood crosses the placenta and enters the
mother's circulation. If mother and baby are not blood group compatible, the
mother becomes sensitised to certain antigens in the baby's blood, usually the
Rhesus D antigen, and subsequent pregnancies of the same group will be attacked
by the antibodies thus formed, causing HDN.
Although delivery is the time that this 'transplacental bleed' usually occurs, it has been reported that occasionally 'leaks' across the placenta happen earlier in pregnancy. 1 The risk and severity of a transplacental bleed is considerably increased in traumatic manipulative procedures during labour such as manual removal of the placenta or Caesarean Section. 2
Sensitisation to anti-D is the most serious and well documented cause of HDN, however other Rh antibodies (especially anti-c) are sometimes involved. 3
Rh(D) HDN can be prevented by administering prophylactic anti-D to all Rh(D) negative mothers within 60 hours of delivery. This is standard practice in many countries. However the standard dose of prophylactic anti-D may not be sufficient for all patients and in order to identify those that need further treatment it is necessary to assess the extent of any transplacental bleed. In order to do this a blood sample should be taken from the mother within 2 hours of delivery and examined for the presence of foetal cells by the Kleihauer method. 4
References
1. Higgins C. Prevention of Haemolytic Disease of the Newborn. Biomedical Scientist. 1999; Sept: 706.
2. Zipursky A, et al. Transplacental fetal haemorrhage after placental
injury during delivery or amniocentesis. Lancet. 1963;
ii: 493-494.
3. Hardy J, Napier JA. Red cell antibodies detected in antenatal tests on
rhesus positive women in South and mid-Wales 1948 to 1978. Br J Obstet Gynaecol. 1981;
88: 91-100.
4. Dacie, Lewis. Haemolytic Disease of the Newborn. In: Practical Haematology, 6th Ed. 1985 p373 Churchill Livingstone.
Click here to return to the Guest Medical Kleihauer Test kit.