Weak Rh typing

[LKSchroed]

We still type our patients using the tube method.  The debate come with the strength of the Anti D reaction.  Some techs call any reaction Rh positive.  Some techs believe the reaction must be 2+ or stronger to be Rh positive.  Our current SOP is not specific.

 

Any suggestions?

[Malcolm Needs ☆]

I would suggest that a datasheet, or something similar, is made available with, if you like, "standard reaction strengths" and, if possible, photographs of these reaction strengths (much better than drawings) and then the staff would have to follow the protocol.

Obviously, whoever is in charge would have to decide what reactions merit what strength, and then what the results should be called (i.e. positive, negative, weak, etc), just so there is some form of standardisation.

[Dansket]

Are you using a Blood Bank computer system? If so, it could be configured to interpret weak reactivity with anti-D. Does your antisera's manufacturer direction insert address this issue? After you have done all this then I would echo Malcolm's post.

Standardization is the key to resolving these types of issues and controversies.

[epfeiffer]

We just had this debate at my facility.  There is another thread here which contained a survey as to how other people are handling this exact issue. I believe a majority of people polled were calling any positive reaction D positive.  Then there were a few people who were calling it negative with a comment.  That thread had more to do with Rhogam I believe.

[Malcolm Needs ☆]

Take a look at the Commentary in the latest edition of Transfusion.