SarahE

I looked up Method 5-3 "Using Antibody Titration Studies to Assist in Early Detection of Hemolytic Disease of the Fetus and Newborn" in the AABB Technical Manual, 18 edition -- One of the NOTES states: "Do not use enhancement techniques [albumin, polyethylene glycol, low-ionic-strength saline (LISS)] or enzyme-treated red cells because falsely elevated titers may be obtained.  Gel testing is not recommended."
The next note states: "LISS should not be used as a diluent in titration studies; nonspecific uptake of globulins may occur in serum-LISS dilutions."

Another caveat about doing titrations on the Vision is that it always runs all 10 (or 12?) dilutions.  That will burn through a lot of reagent cells unnecessarily on a titer of 4!  I agree with those above that it is critical that the OB/GYNs know that you are using a method that gives different results than their textbooks are based on.  Every gel titer result should go out with a comment explaining how its results correlate to the literature for further evaluation of the pregnant person.  At least nowadays they are likely to follow with Doppler ultrasounds rather than riskier, invasive amniocentesis.  I think a review of the CAP survey results is very enlightening.

I am looking at the Participant Summary for latest CAP proficiency, anti-D titer.  For tube testing using the "uniform procedure tube method" that CAP suggests, they reported the following results: 333 participants, mode 64, consensus range 16 to 256.  For Gel testing "uniform procedure gel method", 138 participants, mode 256, consensus range 64 to 1024.  Per CAP, Consensus is determined by the Mode +/- two of the most frequent titers.
It looks like in the previous 2 surveys for the gel anti-D titers, the mode for gel was 1 to 2 dilutions higher than tube, but so was the consensus range.  It seems like there are a fair number of labs reporting gel and if you report that as your method you should be compared to other gel titer users.  I would also think as more instruments are implemented that can do gel titers, the number reporting gel will go up. 
And of course what ever you do, perform method correlation and communicate with the obstetricians any changes they may see in titer results.  We are contemplating this also. 
Also I am little confused by ""Do you want it to be faster and more hands-off or more exact?"  It seems to me that automated titers in gel should be much more reproducible. 
We are just starting to look in to performing titers on Vision.

We do our titers in tube. Years back when a lot of places had switched or were getting ready to switch to gel there was a conversation about the difference in titers due to sensitivity of gel. The basic conclusion at least in our geographical patient care area: we didn't want physicians to be getting different titers from different labs solely due to differing methodologies as it could lead to unnecessary concern/procedures for the patient. So we all stick with tube method.
In those instances where we detect the antibody by a more sensitive method i.e. gel or Capture but the titer is negative then we report the antibody titer as less than 1 (<1).
Jan
 

We were doing titers in the gel and kept failing our CAP surveys for titers. They were always one titer too high (CAP gives you a 3 titer range the results can be within to pass). After investigation (I was new at this job at the time) I found where the Technical Manual says that they shouldn't be performed in gel. (Like SMILLER says above). It goes on to state that there is a danger with interpretation by the physician and the higher results of unnecessary invasive procedures performed due to that combination. They, strangely, do not tell what studies they base that comment on. We switched to the tube method and haven't failed a survey since.
We are in the process of deciding on new Blood Bank automation. When we saw the Vision, that seemed to be one of the "hot" selling points - the ability to perform titers. We questioned them about how they felt about it being contrary to AABB recommendations to do titers in the gel. The response was something like, "Do you want it to be faster and more hands-off or more exact? We would rather see it be more hands-off." (Not a direct quote, but you get the picture.) Personally, I would prefer the "exact" results to one that may or may not be too high. I would also prefer to pass my CAP competency surveys!
Just saying.

We are a small facility which uses manual gel technology. We rarely see titers ordered.  However, when reporting an antibody on a pregnant patient (detected and identified in gel) we faced this dilemma: the antibody was so weak it was not detectable in tube. We then started using gel for titers with the understanding that it is the change in titer over time that is significant.  For proficiency, we use the split sample method every 6 months.  CAP and State (NJ)  inspectors have been OK with this.

On p. 563 of AABB Tech Manual 18th edition, it only mentions that titer methods other than "saline AHG 60 minute incubation" in tube may result in higher titers and "should be validated with clinical findings" (see Malcolm's post, above).  So it does not seem to say one cannot use gel or other methods, just that you need to document validation.
I have always been a bit uncomfortable with identifying an antibody with gel (for a prenatal), then doing the titers in tube.  But then again, I guess it is the comparison of the series of tube titers that they are looking at.
Scott

The AABB Technical Manual states that antibody titers should not be performed using gel technology, so we revised our procedure to go back to tube method.