Ephraim Posted May 21, 2007 Share Posted May 21, 2007 Hey, everyone! Do you have a policy for timing of the blood draw for postpartum Rhig?AABB says that it should preferably be drawn within one hour of delivery. Our nurses are not happy with this. Has anyone seen studies of survival of fetal cells in the Momma?Thanks for your input!Ephraim Link to comment Share on other sites More sharing options...
rcurrie Posted May 22, 2007 Share Posted May 22, 2007 I don't know that there are any survival studies out there. I am giving you the link to a related article here: http://humupd.oxfordjournals.org/cgi/reprint/8/6/493.pdf Fetal cells can be destroyed by the T-cell mediated maternal cellular immune system attack. The purpose of RHIG is to facilitate the removal of those cells from maternal circulation. So, does it really matter how the cells are removed, be it by the reticuloendothelial system or by T-cell mediated response? I don't know. That's the question. If it doesn't matter, then the calculation of RHIG dose is dependent on what is circulating at the time the specimen was collected, and it shouldn't matter when the specimen was collected as long as you meet the guidelines for giving RHIG. My reasoning may be faulty here, so if anyone has a better answer, I would like to hear it. BC Link to comment Share on other sites More sharing options...
Mabel Adams Posted May 23, 2007 Share Posted May 23, 2007 The Gamma/Immucor Fetal Bleed screening test package insert says samples should be drawn at least an hour but then as soon as possible after delivery.I remember that mom and baby being ABO incompatible was originally found to be protective for Rh sensitization. This implies that the baby's ABO incompatible red cells were destroyed intravascularly in the mom so were never presented to the immune system. Since ABO compatible cells probably would have normal survival in the mom, it has always seemed to me like not a very big deal, but I don't have the science to back it up. I wonder what the recommendations in the package insert are based on. Hmm. Link to comment Share on other sites More sharing options...
Ephraim Posted May 23, 2007 Author Share Posted May 23, 2007 Thanks for your quick replies. We polled area hospitals. Their time varied from 2 hours post delivery to before they depart (they seemed satisfied with whenever, as long as they got the shot in within 72 hours)! Link to comment Share on other sites More sharing options...
Yanxia Posted May 24, 2007 Share Posted May 24, 2007 The fetal's RBCs are taken with the mother's blood stream, it can be catched by mother's spleen and liver and at these organs the antigen presenting occur,then the circulating fetal RBCs will be less ,so I think it is better to draw blood sample as quick as possible. Link to comment Share on other sites More sharing options...
Yanxia Posted May 25, 2007 Share Posted May 25, 2007 Sorry, the organ is spleen not liver. I have seen a kind of opinion said the sample should be drawn 30-45min after delivery,it will give time to let the fetal blood disperse within the mother's blood stream. See here http://www.bcshguidelines.com/pdf/pregnancy_070606.pdf Link to comment Share on other sites More sharing options...
Yanxia Posted May 27, 2007 Share Posted May 27, 2007 But the blood circulation is so fast that it just take 20s to complete one circle. I think the time of 30-45min is too long. Link to comment Share on other sites More sharing options...
Yanxia Posted May 30, 2007 Share Posted May 30, 2007 I just read a book says:the postpartum blood sample which used to do the FMH test should be draw as soon as after the injection of anti-D . Link to comment Share on other sites More sharing options...
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