COM.30840 Pipette Carryover

[jalomahe]

For everyone on here with automated blood bank equipment especially Immucor Echo: what do you have in place for this CAP requirement? Do you make a high titer specimen to run? How high of a titer and what do use to make it?

Immucor studies for Echo show that carryover does not occur with an antibody titer up to 5120 so where should my titer point be for the requirement?

I'm trying to think of a way to do this without making myself and everyone else in the department crazy.

COM.30840 Pipette Carryover Phase 

The laboratory evaluates its automatic pipetting systems for carryover.

NOTE: The laboratory must have written procedures for evaluating whether carryover effects are present. This requirement applies to both stand-alone pipette systems and to sample pipettes integrated with analytic instruments. One suggested method to study carryover is to run known high patient samples, followed by known low samples to see if the results of the low-level material are affected. If carryover is detected, the laboratory must determine the analyte concentration above which subsequent samples may be affected, and define this value in the procedure. Results of each analytical run must be reviewed to ensure that no results exceed this level. If results that exceed the defined level are detected, then the appropriate course of action must be defined (repeat analysis of subsequent samples, for example). Carryover studies must be performed, as applicable, as part of the initial evaluation of an instrument. (The laboratory may use the data from carryover studies performed by instrument manufacturers, as appropriate.) Carryover studies should be repeated after major maintenance or repair of the pipetting assembly of the instrument. Evaluation for carryover is not required for automatic pipettes that use disposable tips. This requirement is not applicable to coagulation.

Evidence of Compliance:   Record of carryover studies at defined frequency

 

[pbaker]

We used the carryover validation exercise provided by Immucor when we received our instrument.  No problems with CAP.

[DebbieL]

I searched the operator's manual for info and also contacted Immucor about carryover. They basically said there could be carryover but it would be extremely rare since the patient's titer would have to be higher than 5120 and humans do not reach that level. 

So I decided to use the CAP JAT or J series and test 2 or up to 5 in the same run. The positives are generally pretty strong (4+) and there is always at least 1 negative in the bunch. I also look thru the past patient testing and find at least 3 strong positive (3-4+) patients with either a negative patient in the same run or the next patient is negative and print their results. I write it all up on a form and attach the printouts to prove there is no carryover. I haven't been inspected since I came up with this but it seems reasonable, is not too hard to do.

The only alternative is to use straight antisera and I'm not willing to do that twice a year. I would be interested in what others are doing to meet this standard.

[Shelby56]

We are using a "known" high titer (4+) commercial antisera- run in line with a known negative plasma....after pipetting the 4+, the known negative is expected to be negative. 

 

[DebbieL]

Shelby56. Would you please give me an example of a "known" high titer commercial antisera? I'm thinking Anti-E or Anti-C since they usually give 4+ results. Or do you have something specific you order just for this evaluation?

THX

[Malcolm Needs ☆]

Just because an antibody is avid, it does not mean that it is high titre; the two are not identical.

[Shelby56]

Hahaha this is a great group- na just good old anti-D that is 4+ and would cling or carryover on the probe

[DebWerner]

I just contacted CAP and this was their response:

[AMcCord]

2 hours ago, DebWerner said:

I just contacted CAP and this was their response:

Thanks for sharing that info!

[RKB1988]

On 9/30/2020 at 9:18 AM, Malcolm Needs said:

Just because an antibody is avid, it does not mean that it is high titre; the two are not identical.

So Malcolm, should we perform titer on our "strong reacting antibody" before we do the carryover study to ensure that the titer is >5210?  What if we use straight Anti D and ran a patient with a known negative screen behind it?

 

 

[Malcolm Needs ☆]

1 hour ago, RKB1988 said:

So Malcolm, should we perform titer on our "strong reacting antibody" before we do the carryover study to ensure that the titer is >5210?  What if we use straight Anti D and ran a patient with a known negative screen behind it?

 

 

 

I wouldn't argue with that for a moment, but it is still true that avidity and high titre are neither synonymous, nor identical.