SbbPerson

I actually didn't have to google the answer for this one! I knew that Landsteiner discovered ABO typing at the beginning of the 20th century :)

Are you doing the immediate spin for a crossmatch or antibody screen? Well, we use the prewarm method for Cold agglutinins. We enter the results to the prewarm technique which is Negative, so the computer doesn't have a cow. Then we write in the test comments that the prewarm technique was used due to cold agglutinin, or history of cold agglutinin.

I think there are a lot of variables that you, and your medical director, need to consider.
The biggest is your patient population. 
Do you have a lot of cancer patients taking monoclonal antibody drugs? Do you have a lot of maternity patients? Do you have a lot of antibody positive patients? The only correct answer is to test 100% of the samples to be 100% sure.  That is not practical, and no one would ever suggest that.
Scan the FDA guidance documents to see if you find any relevant ones.
Here are a couple of unrelated ones:
https://www.fda.gov/files/drugs/published/Process-Validation--General-Principles-and-Practices.pdf
https://www.fda.gov/files/drugs/published/Bioanalytical-Method-Validation-Guidance-for-Industry.pdf
For a NEW process that we were unfamiliar with, I always went with 385, regardless of the population size.  We migrated a patient database with millions of records from our homegrown system to a commercial system, we tested different scenarios 385 times.
As time went on, and we grew more confident with that particular software system, and continuously found no errors, we reduced it, slowly, over each validation.
The key point is that you and your medical director need to have a sound, and justified plan.  Your primary goal is to protect your patients.  Your secondary goal is not to get closed down.
Should you test every sample, no.
Should you test 20 samples for a process you have never performed before, no.
I suggest looking at some statistics sites and determining what works best for you.
Here's just one, there are MANY: https://www.calculator.net/sample-size-calculator.html?type=1&cl=95&ci=5&pp=50&ps=&x=Calculate
 

I have never used the Vision, but I googled it and looks like the FDA did a carryover study on it. I attached it. It is from 2019, sorry. Maybe you can find something more current. Good luck. 
BK190399-Summary.pdf

Either way, you learned. 

To be honest,  I really had no clue on what the answer was. I googled it. 

I worked with Harvey at a hospital in Boston.  Then when he went out on his own, we worked together to develop several products.  One was corrugated plastic boxes to put in Igloo coolers that kept the blood away from the ice.  He bought sheets of plastic and experimented with welding and gluing the boxes together.  We finally got one that worked, so we bought a ton of them from him.  Then we moved on to Credo coolers.  He was great like that.  We'd present a problem, he'd help us build it, and then he'd often add it to his product list.
Yes, he made us custom racks, but those have all died, and I have not been with that hospital for a while now, so I am not sure what they are doing.

Thank you so much everyone!

Gosh this topic is kinda of wild, lol

https://www.bio-rad.com/en-us/product/id-working-tables?ID=M17LIB15
Home Products Clinical Diagnostics Blood Typing & Antibody Detection Semi Automated Systems and Manual Workplace ID-Working Tables Bio-Rad has Gel and Tube Racks that should work, maybe better.   "ID-Working Tables" item 009660
You will have to log in at their website to get the price.  
Hope this helps.
 

Hello everyone, 
Here is a new 100% educational opportunity (with PACE credits) for those who are interested in FNAIT. Here is the link to register Webinar | Bio-Rad
 

Wescott Labs used to custom make them,  Sadly, Harvey passed away and his wife gave up the business. 

That's a VERY specialized rack. I suspect the originals must have come from Ortho many moons ago. If Ortho doesn't have any more, I doubt any of the typical suppliers would carry them. Perhaps one of the new suppliers of gel cards might have something (e.g., Grifols) ?
One can always get something custom-made, but $$$$$.
Good luck.

Does anyone have a lead where I can find the gel crossmatch rack?

Marketlab has none. I tried Fisher Scientific.. nothing. 

I am looking for this type of crossmatch rack where I can do tube and gel on the side... Orto doesn't have one either..  Help. Thank you!
 

Aah okay, I guess you answered your own question. The mixed field C result is perhaps due to the dual population of blood transfused. Some may have been C+ and some C-. c+ is a common antigen, almost 80% of Caucasians have it.  That could explain the strong c 4+.  Most place don't do phenotyping after multiple transfusions because of possible dual rbc population , so yes, Townsend is right, "honor the genotyping and provide E-, c-, and K- red cells for this patient moving forward"(Townsend). 

I have the official conversion guide from Ortho and it doesn't recommend any specific QC apart from the general QC of the method it alludes to (the general MTS procedure manual).  I mention visual inspection of cell button size in my SOP.  Has always covered it in the past, but you know how it goes...
Quick Reference Quide - Conversion.pdf

I thought for the first time I would share one of the educational webinars we have been producing with the ISBT because it is a fascinating topic addressed by a great lecturer (Sue Johnson).
So do miss out on the opportunity to watch the recording of this ISBT educational webinar Could it be drugs? How to differentiate AIHA from DIIHA Start zoom webinar | The International Society of Blood Transfusion (ISBT)
 

We would honor the molecular typing and provide E-, c-, and K- red cells for this patient moving forward.  Your serologic typing results are not valid due to recent transfusion, and this isn't an uncommon genotype for a thalassemia patient.  Unfortunately this means that the patient received c pos units (when you gave C-, K- red cells), but that was the best you could do without knowing that information before the first transfusion was ordered at your facility.  We come across this frequently with new/relocated sickle and thalassemia patients.

Hi! My facility performs antibody titers in Ortho pre-buffered anti-IgG cards and Ortho workstation using Universal Gel Protocol. I am not permitted to straight up share my procedure per facility rules, but I can copy+paste the language for the actual recipe. Note that we use double-dose antigen cells when possible, and ALWAYS maintain the dose of reagent cell throughout preg. I recommend purchasing Ortho's Panel B to always keep a double K. Even though Kell doesn't dose, until it does 
 
Principle:
Antibody titration is a semi quantitative method of determining antibody concentration. Serial twofold dilutions of plasma are prepared and tested for antibody activity. The reciprocal of the highest dilution of serum or plasma that gives a 1+ reaction is referred to as the titer (i.e. 1 in 128 dilution; titer=128). In pregnancy, antibody titration is performed to identify women with significant levels of antibodies which may lead to HDFN, and, for low-titer antibodies, to establish a baseline for comparison with titers found later in pregnancy. The titer and the antibody specificity (in the absence of more invasive tests) guide the obstetrician’s decision to deliver the fetus to avoid fetal complications.
 
Process:
Prepare doubling dilution.
1. Prepare 11 tubes for the master dilution by labeling with the titer "2 4 8 16 32 64 128 256 512 1024 2048"
2. Add 250 uL saline to each tube using a calibrated pipette.
3. To master dilution tube #2, use a calibrated pipette to add 250 uL patient plasma.
4. Discard the pipette tip.
5. With a clean tip, return to master dilution tube #2 and use the pipette to mix contents. Depress and release the plunger in a slow and controlled manner (do not cause frothing) 8-10 times.
6. Express any residual fluid back into the tube and retrieve 250 uL from that tube to be placed in the next tube (tube #4).
7. After expressing the contents of the pipette into tube #4, discard the pipette tip. 8. Using a clean pipette tip, repeat the mixing step in tube #4, and transfer 250 uL of this mixture to tube #8. Discard the pipette tip. Get a clean pipette tip and continue this pattern until you have mixed the contents of tube 2048.
9. Visually inspect the volumes in the tubes. Tubes 2-1024 should have equal volumes (250 uL). Tube 2048 should have a double volume (500 uL). Perform the gel test
10.Label 2 gel cards with the patient’s identifying info.
11.Label 12 wells as follows "neat 2 4 8 16 32 64 128 256 512 1024 2048"
12.For each well, use a calibrated pipette to add 50µL 0.8% reagent red cell. See above for choosing red cell.
13.In the “neat” well, use a calibrated pipette to add 25µL plasma.
14.In the remaining wells, use a calibrated pipette to add 25µL of the master dilution corresponding to each well’s label.
15.Incubate at 37±2°C for the 15 minutes, but no longer than 40 minutes.
16.Centrifuge the gel cards at the preset conditions of 1032±10 RPMs for 10 minutes.
17.Read the front and the back of each microtube macroscopically and record reactions as described in the interpretation section of the corresponding MTS Gel Card package
 
Results: The titer is reported as the reciprocal of the highest dilution of serum at which 1+ agglutination is observed. A titer ≥64i (anti-D) is considered significant and may warrant monitoring for HDFN by cordocentesis, high-resolution ultra-sound, or examination of the amniotic fluid for bilirubin pigmentation.
 
Notes:
1. Titration studies should be performed upon initial detection of the antibody.
2. When the decision has been made to monitor the pregnancy by an invasive procedure such as amniocentesis, no further titrations are warranted.
3. For antibodies to low-incidence antigens, consider using paternal RBC’s having established that father carries the low-incidence antigen.
4. Failure to obtain the correct result may be cause by a. Incorrect technique, notably, failure to use separate pipette tips for each dilution. b. Failure to mix thawed frozen plasma.
5. The gel technique is more sensitive than earlier traditional tube methods and typically results 2 dilutions higher than the tube method. The historic literature describing the clinical importance of different titers tacitly assumes the tube method, so caution should be used when referencing texts that do not specify “by gel technique”.

I just answered this question.

My Score PASS  

Immunoglobulin
This question and answer was originally published on Lab Tests Guide.
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Submitter Cliff Category BloodBankTalk Submitted 10/03/2024  

This is a great book :)

Thank you so much I will have a look at that! 😊

Thanks Lorna.  I'll have a look and see what I can provide but, as I see that you are working in the Isle of Man, may I suggest you get a copy of the BCSH Guideline "Pre-Transfusion Compatibility Procedures in Blood Transfusion Laboratories" from 2012 (which is available free on-line - just put in BCSH Guidelines), and these have a few at the end of the Guideline.

In addition, have a look on this site under "Library" at the top of the page, where you might find more than one thing (probably under "Education", but not only there), that will be of use to you.

I have a book called "Antibody Identification: Art of science" . It's by the AABB, and it's chock full of case studies, over 500 pages of them, with questions for all of them.