By Mabel Adams
We have just learned that we have a 32 week pregnant IgA deficient mom admitting tomorrow for observation for the next 2 weeks with plans to deliver at about 34 weeks by C-section because of placenta previa and vasa previa. There is no record of anti-IgA testing that we can see. This is not her first pregnancy--G3P2. She is about 30 years old and was identified as IgA deficient 5 years ago. She is donating 2 autologous RBC and FFP units. I assume there is no extra risk for the baby. We are 3.5 hours' drive from our blood supplier. Any advice appreciated as we create a plan for dealing with possible hemorrhage.
We currently have a 50 year old male in house that had an accident that damaged his foot 3 weeks ago. He arrived septic and has had to have an amputation.
His ABO/Rh gives a B pos with a 4+ anti-D. His gel screen and panel give 1+ results that match up with an anti-D (all others rules out). His autocontrol was positive at 1+ by IgG, neg for compliment. The eluate results matched the original antibody ID. Presently this patient's specimen is on its way to our reference lab. Previous history at another facility lists him as B Pos, screen negative. As far as we know, he has never been transfused.
What are the possibilities (for what appears to be an D auto antibody), and how should he be treated?
By Jennifer G
Has anyone seen an Anti-D go from negative to 2+ positive to negative? We had negative antibody screens on an elderly A Negative woman from 2012 through 2018. 8 RBCs were transfused during this time. In August 2018, the antibody screen was 2+ positive, Anti-D was identified, and she received 1 RBC. In April 2019, the antibody screen was negative on 2 different occasions. The possibility of the August 2018 specimen being the wrong patient seems unlikely since we use hand-labeled separately armbanded specimens. However, I have never seen a true Anti-D behave this way.
We are about to move from using Bio-Rad IH-1000 to Immunocor NEO in our blood bank department. As most of you are already aware, the IH-1000 uses column agglutination technology (CAT), whereas the NEO uses Solid Phase Red Cell Adherence (SPRCA) assay. SPRCA is known to be more sensitive, which is great when picking up on elusive antibodies belonging to Kidd blood group system (I think ). My concern is about the techniques which employ the use of indicator cells that are coated with anti-IgG. It will only pick up on IgG antibodies and none of the IgM antibodies. How significant is this? Is there any way of picking up IgM antibodies using such technique? Or should we not worry since IgM antibody does not usually reaction at 37C?
I have a question, but firstly good old story time for some context. I came across a patient who had positive antibody screen on all three screening cells used (BioRad). I was concerned this may be an auto and pan-reactive, and required units. Performed a monospecific DAT, showing a positive reaction to IgG only. By this time antibody panel finished cooking and showed the patient may have anti-Fya , but couldn't do phenotype. By this time I was nearing my shift so handed it over to my colleague and asked for some units to be crossmatched. However, he refused as DAT was positive and said he rather send the sample to reference laboratory for them to crossmatch. The next day I crossmatched units to verify if it could have been done in our laboratory (just because I am sad that way), and turn out the unit I crossmatched was compatible (which I wasn't surprised about)
Why does positive DAT (or the cause of positive DAT) sometimes interfere with IAT techniques (such as antibody panel and crossmatch) and sometimes it does not? If both use AHG, then wouldn't positive DAT with IgG cause antibody panels shows pan-reactive with red cells? But obviously it doesn't, but I'm trying to figure out why, and I'm sure the answer is quite obvious.
My laboratory seems very hesitant whenever they see anything regarding autoantibodies or positive DAT, and thinks that sample cannot be crossmatched in-house and needs to be sent off without even trying to investigate. Hopefully, by me asking this question, I can explain it back to my colleagues (but obviously take all the credit).
Cheers in advance,