Room Temperature antibody positive cell

[galvania]

I mean an AHG crossmatch at 37°C

[GilTphoto]

Most of the time it will be a cold auto or alloantibody. But a small number of patients may have a newly forming IgM antibody that only reacts at cold temps

I have seen 3 in past 2 years in my hospital, two had an IgM anti-E and one anti-K. Neither reacted at IAT.

The logic to not work it up, is that since the antibody is not yet IgG, only a mild reaction, or deceased RBC survival will occur, and spending time working up the other 95% will be wasted.

Our antibody screens already don't identify all significant antibodies, so we take a risk on the low incidence ones (Cw, V, Di(a), Kp(a), Js(a), etc)

We take the same risk again by only doing I.S. crossmatches. If an anti-Cw was not detected in the screen, a coombs XM of a Cw+ unit would detect it. What is the incidence of this happening? Both a patient with a low incidence antibody and a unit that is antigen positive, so it's considered low risk.

My personal feelings is that antibody ID is the fun part of Blood Bank. Negatives all day long is boring!

While you can attempt to not detect them by only doing a screen at 37 and IAT, they still rear their heads and are detected in the I.S. crossmatch, or the ABO reverse.

The only way to eliminate seeing them in the crossmatch, is to go electronic XM, which is essentially not doing a crossmatch at all.

Another way to avoid detecting cold antobodies, is to not delay I.S. readings and to not use a microscope. The purpose of an Immediate spin phase is to check for ABO compatibility, and those reactions are usually very strong. Don't look so close!

If still detected, we work them up by first doing a short cold panel.

Screening cells I, II, Auto Control, (an O cord is optional), and ABO compatible cells if not type O

A1, A2 cells if type A

B cells if type B

A1, A2, B cells if type AB

Immediate spin and 15 min room temp, (4C phase usually not necessary to ID as almost everyone reacts at this temp)

If the Auto is positive, we can stop right there. Cold autoantibody reported

If the patient is an A or AB, and only A1 cells reacting, then we check for subgroup of A with anti-A1 (A1 Lectin)

Otherwise we do a full panel to identify the antibody, significant or not

Being only a medium sized hospital, the workload usually allows time for identification. Having the techs gain more experience with identification, so as to not panic when they get an antibody. Small places have more General techs working multiple departments may not have a lot of antibody ID experience, so any chance to teach them more skills is taken, even if ID is for an insignifcant antibody only, it builds confidence when working up a significant one.

[Malcolm Needs ☆]

Good post!