KB stain question

[John C. Staley]

One of my more experienced staff members who is new to the team has been telling a couple of the staff who are less experienced that if a baby is wD positive they should do a KB stain instead of a Gamma Fetal Screen becasue of the wD being a weaker expression and may therefore give a false negative fetal screen result.

Before I ask her about it I thought I would run it past you folks. I can't fault the logic but I've never heard such a thing and can not find it referenced in the Gamma Fetal Screen package insert.

Anyone else familiar with this train of thought?

:raincloud

[BSIPHERD]

Yes, this is what we do also. The AABB Technical Manual 15th ed (p. 794) states about the rosette test "If the infant's cells are shown to be weak D, a negative result on the mother's specimen should be interpreted with caution. In this situation, a quantitative test that does not rely on D antigen expression should be performed."

[Mabel Adams]

That's what I had heard too. I think it is even in the notes of our procedure.

[janet]

We do the same, also go to the KB if for some reason the RhIg was given before the sample was drawn.

[estiner]

Speaking of KB stains - has anyone noticed a sharp increase in requests for the KB stain on mother's with moderate or higher bleeds on both Rh neg and Rh pos. One of my new OB doctors told me it is a new recommendation by the OB-GYN literature to study if there is a difference between the Rh neg and Rh pos patients. I am trying to find information on this "new recommendation" so I can understand the logic behind the study.

[xmbeti]

It is referenced in the 12/05 revision of the Immucor Fetal Bleed Screening Test product insert.

It is under "Limitations" #1, second sentence.

"If the infant's red blood cells possess a weak D antigen, the test may not detect a feto-maternal hemorrhage exceeding 30 ml of whole blood.

This is my first posting, so I hope this works!

[bbbirder]

I agree with the need to do the Fetal Cell Stain on Mom if baby is a weak-D. The problem we encounter is making sure this gets communicated the way it should...so the tech testing the Mom's blood knows this.

Do you require the techs to review the cord blood results every time they do a RhoGam workup?

Does anyone have a cute computer fix for this sort of thing?

Linda Frederick

[KKidd]

I agree with the need to do the Fetal Cell Stain on Mom if baby is a weak-D. The problem we encounter is making sure this gets communicated the way it should...so the tech testing the Mom's blood knows this.

Do you require the techs to review the cord blood results every time they do a RhoGam workup?

Does anyone have a cute computer fix for this sort of thing?

Linda Frederick

I developed a test called "Fetal Bleed Required". It is attached to the RhIG workup. If the tech answers Yes, a canned text pops up stating that if the infant is weak D pos, a KBStain must be done instead of a fetal bleed. This answer also reflexes an order for a fetal screen. The fetal screen can be deleted and KBStain added if appropriate.

[Mary]

What computer system are you using?

[KKidd]

What computer system are you using?

We use Meditech ver. 5.6.1 magic. I don't know how building the query as a non-billable, non-repoertable test would work with another system.

[Mabel Adams]

It should be possible in Meditech to build a rule that looks at the cord results for weak D and at least pops up a message box to remind the tech to follow through with the KB testing rather than Fetal screen.

We currently use a T test on the cord blood where we check the mom's type to make sure she is Rh neg, then we put in a comment stating that the mom needs a fetal bleed test ordered. This prints out as a message to the OB floor to know what to do next. It probably wouldn't be too hard to make it look at the cord results too and even turn out a statement that they should order a KB on the mom instead.

The biggest problem with computers in this case is that the cord blood and the fetal bleed test are on two different patients so various test reflexing systems don't work.