Dropping wD testing.

[John C. Staley]

We are finally considering dropping wD testing on our patients (excluding newborns for mom's RhIg determination). One of the more conservative medical directors is concerned about wasting Rh neg units and exposing women to RhIG who don't need it. Can any of you who have dropped routine wD testing provide any data or references to address her concerns?

Thanks

John

[johna]

Our lab is dealing almost exclusively with prenatal patients and ABO/Rh typing is performed on the Olympus PK-7200. The Olympus automatically performs a "weak D" test in a separate channel from the initial D typing. We repeat any "weak Ds" manually as a secondary check before reporting.

I'd fully support the elimination of "weak D" testing if it wouldn't throw our docs into a turmoil. We already run into situations in which we report "Rh-positive, weak D" and a hospital reports "Rh-negative". Unfortunately we do not have the luxury of receiving social security numbers or something akin to a hospital number which would allow us to cross-reference previous with current results. Therefore by dropping "weak D" we'd wind up with a small number of reports which are in disagreement with previous ones and we wouldn't be aware of that until a nurse or OB calls screaming that we've made a miscue.

On the other side of the coin, from a hospital perspective you'd be able to track any discrepancies between past & current results through the SS# or hospital number before results were released. I don't have any solid data but I'm sure that from an economic perspective the "wastage" of RhIg is minimal compared to the reagent/labor cost savings by dropping "weak D".

[MTINGA]

We no longer perform weak D testing except for infant D testing to determine mom's Rhogam status. It has been wonderful in that we no longer have to go through nurses and doc calling to question what O pos, weak D means. That just does not make sense to most people who look at charts. We have not wasted any Rh negative units because before we still gave Rh negative blood to patients that were weak D positive. So what good was the testing except for our information. It wasted reagent and tech time doing the testing and answering questions about what it meant. So glad we had a director open to new ideas and suggestions.

[S.Hunt]

John,

We dropped Weak D testing 3 years ago. Since we called the weak D patients "Rh negative - weak D positive" and treated them as Rh negative when transfusing them, we did not see an increas in the transfusion of Rh negative blood. We still carry D negative testing thr to coombs on all cord and neonatal heelsticks, especially on babies born to Rh negative mothers. Also our conservative OB/GYN group always gave Rho(D) IgG to D Negastive-weak D positive mothers so increased use of Rho(D) IgG did not occur. For us it has been a saving in reagent and tech time.

I do have a question however - since there have been some cases of Anti-D being made by D Negative-weak D positive patients, will you give Rh Positive Red Cells to weak D poitive patients?

[adiescast]

This is directed mostly to johna:

If you are not a hospital lab and your director approves dropping the weak D test, you could send out information to your clients to let them know when and why you are dropping it. This may forstall any complaints about the difference in your reports. When our hospital lab dropped it, we did not hear any complaints at all.

[Sandy Smietana]

John

We dropped weak D testing for all patients except processing autologous donors, cord bloods and infants under 6 months. Basically what I have to say has been said by other people. We did not see an increased usage of Rh negative blood because the units were crossmatched before the weak D test was completed so the few Weak D positive patients we had received Rh negative units.

Many of our OB physicians prescribed Rh Immune Globulin for their Weak D positive patients "just in case". Dropping the test has been a savings in time and money. It was a constant source of confusion for the doctors and nurses when they had patient testing performed at laboratories that had dropped the weakk D testing while we still performed it. They had conflecting results on the patient's chart, this has eliminated a lot of confusion for both the blood bank staff and medical staff. We have not receive any negative responses from the medical staff to date.

Sandy