How do you report a titer result when it is all negative, even the 1:1 shows no reaction?  The antibody screen was 1+ with anti-D identified, but it did not titer out.  Is it correct to report: Titer <1?

That is how we report such findings.

We report it as titer 0.5.

I though Anti-D was quantification, not titre?

No Autie-D.  The quantification of anti-D (and anti-c) is largely only performed in the UK (although I think I'm correct in saying that it is also used to a certain extent in Eire, Australia, France, New Zealand and Scandinavia) and, as the machines are coming to the end of their useful life, we (the UK Blood Services) are looking at other ways of performing anti-D and anti-c estimation, which may or may not involve titration and/or the use of a FACS machine - nothing has been decided yet.  Even when a decision is made, we then have to go through validation, change control, etc etc etc.

How do you report a titer result when it is all negative, even the 1:1 shows no reaction?  The antibody screen was 1+ with anti-D identified, but it did not titer out.  Is it correct to report: Titer <1?

too weak to titer.

This can be more common with gel screening and tube titer. 

We also use "too weak to titer"

too weak to titer, I agree with Eagle Eye.

I report as < 1:1

we report as titer <1

I report as < 1:1

Anorris, I am afraid your report looks like a dilution rather than a titer.

too weak to titer.

This can be more common with gel screening and tube titer. 

 

We've seen this occasionally with ProVue vs manual gel.

Pet peeve topic....

 

There is no such thing as a titer of "less than one".  It either meets the reaction criteria (generally 1+ is the standard, but other strengths might be in use) or it doesn't. 

 

The first tube in a standard titration contains nothing but raw sample and cells...so I'm not sure how you would treat the raw sample to obtain a titer of "less than one".

 

A sample that has a +w reaction in tube one should be reported out as a titer of 0 if your standard for interpreting a titer result is higher than the +w reaction observed.

 

Ok....I feel better now. 

I remember when I was a student, one of my  classmate report tube one no reaction with titer of less than zero, my teacher said you owe it some antibodies.

Just one of many interesting in study. I don't think report titer O.5 is wrong, because some patient they have 2 drop serum and 1 drop cells tube reaction ,some not. To differ this I will report 0.5.

I don't understand how, if you use the same technique for your antibody screen and your titre you can get a 1+ result in the antibody screen and negative in the titre - unless you are using a very different cell pheno.  I also don't understand why anyone would want to titrate an anti-D with a 1+ reaction.  What is the reasoning behind this?

Confused!

Anna, I think many places use a more sensitive technique for the screen (LISS, PEG, gel etc) than the titer.

Ok - so that would explain the difference - I am a bit confused as to why you would do that, though - and I still don't understand WHY you would want to titrate such a weak anti-D

I don't understand how, if you use the same technique for your antibody screen and your titre you can get a 1+ result in the antibody screen and negative in the titre - unless you are using a very different cell pheno.  I also don't understand why anyone would want to titrate an anti-D with a 1+ reaction.  What is the reasoning behind this?

Confused!

I don't know how to do tube one of titer in your lab, in China, we will use one drop of serum/plasma and one drop of suspended cells as tube one or we call it titer 1.

Antibodies screening and panels we use 2 drops of serum/plasma and one drop of cells to do it. So in some case, antibodies screening /panel is pos ,and antibodies titer is below 1. To report it as titer 0.5 is not about clinical significance, just to differ from some case panel is neg .

If we say its clinical significance, maybe about the appearance timing of this antibody.

We use "Titer too low to measure: Enhancment reagents used for antibody identification are not recommended for titers."  We do not enhance our titers as we do antibody identifications to prevent falsly high titers.  We treat it as in vivo where we see how it demonstrates without the addition of enhancment reagents.