Is RhIG clinically significant?

[dcubed]

For those institutions that employ the electronic crossmatch; do you regard passive anti D found in a patient's plasma/serum as clinically significant? That is, do you do an AHG crossmatch for these patients or have you devised a way to issue PRBC's with either an electronic or immediate spin crossmatch? Thanks in advance.

[vilma_mt]

I don't think your system would allow you to proceed to electronic crossmatch due to the positive antibody screen.Even if lab knows patient received Rhogam, In routine setting you would still proceed performing antibody panel and IgG crossmatch. Besides, how can you tell it's due to Rhogam and that patient has not been sensitized and already produced anti-D? I thought the difference between the two is presence/titer when patient's blood is tested few weeks after last Rhogam administration. Rhogam will not be detected after few weeks of last dose.

http://www.fda.gov/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guidances/Blood/ucm073253.htm#ELEMENTSOFACOMPUTERCROSSMATCHSYSTEM

Edited April 13, 2010 by vilma_mt

[richardsonj]

[quote= Rhogam will not be detected after few weeks of last dose.

We have picked up Rhogam as far as three months after the last dose using gel or solid phase technology. We do full crossmatches on those patient's due to the positive antibody screen. For one, you are not sure that it IS actually from Rhogam and two, it is easier to have a consistent protocol.

[Deny Morlino]

The MTS cards will pick up the RhIg as far as 3 months. I seem to recall at least one case longer than 3 months, but cannot recall the details at the moment. It has been some time since we have used tube as our primary method, but the detection period for RhIg is usually much shorter with tube if I recall.

[tricore]

We started performing EC in the days when you had to apply to FDA for a variance (1995) to use it. The FDA reviewer told me that we could not call passive anti-D from RHIG clinically insignifigant, even though they were females of child bearing age and would always receive Rh negative blood. He said EC was only for "pure" patients. Of course, your computer system should not allow EC if the screen is positive. Fortunately most women who have a passive anti-D do not require transfusion. If they do require RBCs it is usually an emergency.

[BSIPHERD]

For Rh negative patients with passive Anti-D secondary to RhIG administration, we do not consider it clinically signficant and don't require AHG crossmatches. We do I.S. only.

However, when Rh Positive patient get RhIG for ITP treatment, we do consider this clinically significant. We give Rh Neg blood and do both I.S. and AHG crossmatches.

We don't do electronic crossmatching.

Belva in Lincoln

[adiescast]

We Coombs crossmatch these patients until the antibody is not detectable. Then we go to immediate spin crossmatch. The computer will not return to electronic crossmatch if the screen is ever positive.