Rh Control and other QC questions

[bluetrout]

The lab I just started working at uses 22% Albumin for their Rh control.

Is this ok?

Also they don't use QC sera and cells for QC. Instead they test some of the reagents against themselves and use a dilute anti-D and anti-K for checking the two screening cells. I have never heard of doing QC this way.

Is this ok?

[galvania]

A control reagent should really contain all the 'ingredients' that the reagent contains, with the exception of the antibody, and should have the same protein concentration. That includes buffers, any antibiotics that might be in the reagent etc etc. 22% albumin used to be used in the days of potentiated human anti-D but wasn't really very satisfactory even then. What type of anti-D are you using?

Dilute anti-D would be OK - IF the dilution is standardised.....Can't really see the advantage of using an anti-K as well..

Just my opinion

Anna

[OPUS104]

The Anti-D that we use states in the insert that no Rh control is necessary due to the protein levels...... what does your insert say? We do not use "commercial" controls to perform QC on our reagents each day. I can't imagine how many we would need to match all of the protein levels and antibodies present in the large number (and variety) of reagent panels, cells and anti-sera we use in one day. The FDA (we are a collection center) has never had a problem with the QC and they have looked at it specifically one at least one visit. Maybe we just got lucky!

Hope this helps.

[Lcsmrz]

We use 6% Alb if a cell control is required -- our package inserts recommend this. Sometimes it's just the comfort level of the BB supervisor; we have to sleep well at night.

As a small transfusion service, we don't purchase a BB QC kit either, using available reagents to QC each other. The biggest difficulty is the requirement for 1+ to 3+ reactivity with screen cells. We haven't found one that does that in gel yet, so we make our own dilution daily. These kits are not cheap either, so we found an acceptable alternative.

[David Saikin]

I don't think the 1-3+ rule applies for CAP anymore. I was concerned with that when I switched to gel but the standard now only calls for reactivity to be verified; reactivity must be 1+ or greater.

[dcross]

We use 5% albumin in lieu of a manufacturers control. While it is true that most manufacturers say a control is not required for monclonal reagents, if you read the fine print of the package insert, you will probably find a statement like "if a positive DAT is suspected, an albumin control is recommended".

[johna]

As I'm sure the folks that frequent this forum are aware an Rh control is necessary if the patient types as AB+. Personally I've always found it easier to routinely run a 6% albumin control instead of backing up and pulling all the AB+ specimens out of a run. I think that the fact that an in-house prepared Rh control does not contain preservatives or antibiotics is really not an issue. Just an opinion!