RHo Control for AB Rho Pos Patients

[bbkdiane]

Please share what type of control your lab uses for this situation. Do you use commercially prepared Rho Control, Patient Sera/Plasma, Saline, or Diluted 22% albumin to 7-8%. Just curious. Thank you.

[Dawn]

We use a commercially prepared Rh control. We run it in parallel with anti-D for all patients. Our volume is so high that it is easier to treat all ABO/Rh tests the same.

I have worked in places where an Rh control was not used, instead a saline control was run on all AB Pos patients.

[John C. Staley]

We use a commercial Rh control for AB pos patients. After 2 documented tests with negative controls we don't test with the control any longer.

[Jane]

We just use saline for the Rh control

[Gloria]

We use a saline control

[cell1]

We use a commercially prepared Rh control on all AB positive patients.

[CABMT]

We use 6% albumin as negative control.

[adiescast]

We use homemade 6% albumin.

Do you do the control every time an AB positive patient comes in or only the first time?

[bbkdiane]

I would think that the AB RHo patient would have to be control tested each time the full blood type is performed. Performing the test one time might not reflect the serological change in the patient that may be occurring...ie the development of a positive DAT that may interfere with typing.

When we perform the ABO/RH recheck on the same sample (whenever another tech does additional work with the sample) we just use A/B/D. No control.

Thank you for your post.

[bbkdiane]

How do you QC your home made diluted albumin? What do you do, and how often do you do it?

[Sandy L]

We prepare 8% albumin to be used as a control in this instance. Ortho (primary reagent) recommends 6-8% as a control. ImmucorGamma, Series 4, (backupreagent) recommends 6-30%. In the commentary to CAP checklist question TRM.410150 regarding appropriate controls for D testing is the following:

"Monoclonal anti-D reagents do not ordinarily require a separate reagent control. Incorrect assignment of a D-positive phenotype can be ruled out by observing negative reactions in any tube containing red cells and patient serum, or, alternatively, patient cells suspended in 5% bovine albumin." I'm not too sure why they recommend 5% when this is not quite what manufacturers recommend.

Our LIS system is set up to require a control for sample that tests AB D+ or D+ in absence of concurrent ABO testing, so we would run with every patient typing in these 2 instances.

[Kochman]

Some food for thought:

The manufacturers' package insert should tell you what kind of control to run. It is important to note that Anti-D reagents have additives that help the cells resuspend and give cleaner reactions. If you make your own control, it won't have these additives whereas the manufacturers' reagent-matched control should.

Also, using the manufacturers' reagent-matched control can save you some headaches, like how to QC it, how long you can use it, etc. This will all be in the labeling.

[adiescast]

In answer to bbkdiane: We do daily QC on the 6% albumin. We run it against a D positive reagent cell. The expected result, of course, is non-reactive.

In answer to Kochman: Immucor recommends a control made of 6 - 30% bovine albumin in saline, not a manufactured control. As you pointed out, it is important to follow the manufacturer's recommendations.

[MTINGA]

We use 6%Albumin for AB+ control. We use 1 part 22%Albumin to 3 parts saline. We use our commercial red cell control for QC. Albumin control is good until original albumin expiration or cloudiness.

[skopti]

We use a 6% albumin control

[sgoertzen]

Rather than saline, we use 2 drops LISS reagent (N-Hance) for the Rh neg control on all AB Pos patients. The N-Hance idea was suggested to us by our Gamma rep (who had her SBB) many years ago since it is very handy to use directly from your regular reagent rack.