|
|
 |
 |
 |
|
|
|||
|
||||
|
||||
Re: Anti-MFrom: ainsron (ainsron@sbcglobal.net)Thu Mar 27 16:54:33 2008
This is from the ACOG bulletin: * At what antibody titer should an additional evaluation be initiated? The usefulness of maternal serum antibody titers is determined by the patient's reproductive history. For a woman with a history of a previously affected fetus or neonate, serial titer assessment is inadequate for surveillance of fetal anemia. Titer values are reported as the integer of the greatest tube dilution with a positive agglutination reaction. Variation in titer results from different laboratories is not uncommon, so titers should be obtained in the same laboratory when monitoring a patient, and a change of more than one dilution is significant. A critical titer is that titer associated with a significant risk for severe erythroblastosis fetalis and hydrops, and in most centers this is between 1:8 and 1:32. If the initial antibody titer is 1:8 or less, the patient may be monitored with titer assessment every 4 weeks. For patients with alloimmunization involving antigens other than D, similar titer levels should be used to guide care except in Kell-sensitized patients because Kell antibodies do not correlate with fetal status (19). * What ancillary tests should follow identification of maternal antibodies to diagnose hemolytic disease in the fetus? Determination of Paternal Genotype The initial management of a pregnancy involving an alloimmunized patient is determination of the paternal erythrocyte antigen status. If the father is negative for the erythrocyte antigen in question (and it is certain that he is the father of the fetus), further assessment and intervention are unnecessary. In cases of Rh-D alloimmunization in which the father is Rh positive, the probability that he is heterozygous for the D antigen can be reliably estimated by using Rh-D antisera to determine his most likely genotype. This involves mixing antisera, containing antibodies to the D antigen, with the father's cells to determine if the D antigen is present. A positive result is determined by agglutination caused by the cross-linking of the antibody with the corresponding antigen. If the father is homozygous for the D antigen, all his children will be Rh positive; if he is heterozygous, there is a 50% likelihood that each pregnancy will have an Rh-negative fetus that is not at risk of anemia. Given that the genes coding for the D antigen are known, a DNA-based diagnosis is commercially available. This form of diagnosis also can be used to identify a number of minor antigens (C, c, E, and e). Evaluation of alloimmunization to other erythrocyte antigens known to be associated with erythroblastosis fetalis (Table <http://www.acog.org/publications/educational_bulletins/pb075.cfm#table1#tab le1> 1) should be performed in the same manner. Ronald E. Ainsworth, MD, FACOG -----Original Message----- From: ob-gyn-l@obgyn.net [mailto:ob-gyn-l@obgyn.net] On Behalf Of Glen Elrod Sent: Thursday, March 27, 2008 2:58 PM To: Multiple recipients of list OB-GYN-L Subject: Anti-M 35 yo G7P3033 at 9 wks with O+ blood type, no history of transfusion or trauma, has an anti-M antibody on new ob labs. Titer is now pending. Any suggestions of what to do next? Timing of next titer? If less than 1/32 would you do nothing? Thanks, Glen _____ Never miss a thing. Make Yahoo <http://us.rd.yahoo.com/evtQ438/*http:/www.yahoo.com/r/hs> your homepage.
|
|
Return to
|
Mail a New Message to the Forum: ob-gyn-l@obgyn.net Forum Administrator: geffrey.klein@obgyn.net Report Technical Problems: webmaster@obgyn.net Last Updated: Wed Jul 2 04:49:05 2008 |
The American Medical Association is no longer designating CME hours for AMA Category II CME credit. However, physicians themselves may self designate learning activities as Category II CME credit hours if they feel it is of sufficient educational merit and meets the formal definitions of continuing medical education. OBGYN.net believes these interaction in this forum meets these criteria. For further information see the AMA web site.