Screening Antigen Negative Units??

[Skinrash]

1) I'm simply curious if it is an acceptable practice to save patients' plasma with a known Antibody to SCREEN for antigen negative units, then confirm (Test of Record) the antigen typing with our commercially purchased antiserum? If this an acceptable practice, how do we verify and control the screening plasma for use? I was thinking of running two positives and one negative qc with each run. The positives would be one heterzygous cell and one homozygous cell, where the graded results must be at least a 2+. Then my next question is how long is would this screening plasma be good for? I was thinking 2 months, or until the qc is not valid, which ever comes first. Any help with this process would be greatly appreciated. Any procedures that I could use as references, would also be greatly appreciated. This idea has cost saving benefits, but I'm just not sure how to implement it properly.

2) Is there a web site (bloodbanktalk.com or elsewhere) that Blood Banker can swap and share policies and procedures? I'm always looking for references, to help write policies or procedures.

thanks for everyones willingness to share!!! Have a GREAT DAY!

[L106]

This would be fine. Of course, you have to think about the ABO Group of the antibody plasma and what ABO Group of donor units you want to screen.

I wouldn't slap on an arbitrary expiration date the the antibody plasma. Just test it against one heterzygous antigen Pos cell and one antigen Neg cell to assure that it is reacting respectibly. (We sometimes use expired commercial typing antisera for this same purpose of "pre-screening" to find antigen-negative donor units.

As you said, you would then want to confirm the "good" units you have found by testing them with indated commercial typing antisera (along with appropriate control, as usual.)

[David Saikin]

I don't save pt specimens to screen with but I do screen using pt plasma (essentially an AHG xm). The units I find compatible I type with the known antisera and run appropriate controls with that testing. AND I have already done the AHG xm.

[bbville]

I don't know why you would bother with a positive and negative control. You are not using it for any test of record. You are always going to confirm with appropriate antisera. I am assuming you would do this for a patient with an antibody history that is no longer reactive or you could just use the patient.

[ovrwkd]

Here's my rule for saving a patient sample for screening:

Assuming you have a patient sample saved from an identified antibody, this sample should have had all other common alloantibodies ruled out. In essence, you have an unlicensed antisera. And congatulations, you have just become a manufacturer.

If if was an A positive sample and contained anti-Fya, you could use it to screen O and A units for Fya antigen.

You should have a procedure in place to save the information on what is in the container, where it was obtained and when. You need to document the ABO and antibody contained on the container, the originating patient name, MR# and date obtained; this will be your traceable information. The expiration date is arbitrary. When it stops working to give a satisfactory result (2+ is ideal), discard it.

Storing in small alloquats in a -30C freezer reduces the chance of bacterial contamination.

You should run a heterozygous (single dose) positive control as it is necessary to prove it works. Consider the outcome if you did not check and it quit reacting.

This works best when you have a patient with an antibody to a low prevelence antigen. Save money and you can screen your units yourself.

I look at any procedure through the eyes of an inspector. What information would I want to review in your facility if you had a transfusion reaction and had to prove your work.

Good luck

[PammyDQ]

My shift partner and I have been doing this unofficially for years for certain antibodies. For example, we had an O+ patient with a nice strong anti-E and anti-c, and patient with a history of anti-c that is no longer detectable with a transfusion order. So to reduce our use of $$$ anti-c reagent antisera, we will crossmatch units with the anti-E,c plasma, then crossmatch the compatible ones we find with our patient with the anti-c, and then test the compatible units with reagent anti-c antisera.

We have a good supply of frozen positive antibody plasmas which are saved for our students. Generally the antibody reactivity is good for a couple years frozen. For unfrozen samples, we get a couple months or so.

And I ditto what vsummerville stated...why bother with controls...it's just an "off record" screening.

[VACASE]

I agree. If there is a fair amount of patient plasma and you don't want to waste a lot of antisera you can use the patient plasma to narrow down the amount of units you have to test with the commercial antisera. This is in one of our procedures and we don't do QC on the patient plasma.

[VACASE]

Sorry. I meant to say that I aggree with vsummerville.

[Joanne P. Scannell]

I don't agree that 'now you are a manufacturer' and you need to keep all this information on these patient samples, run QC, etc. You are not reporting the test results using this 'unlicensed antisera'. What IS being reported DOES use a licensed product, namely reagent antisera from a bonafide manufacturer. And I'm assuming the required QC is run with that.

Let's not get crazy here ...

[SMW]

Remember that the standard is "components shall be prepared for transfusion that do not contain the corresponding antigen and are serologically crossmtach-compatible." I am not aware of a requriement to screen or test units with a reagent antisera (licensed or unlicensed).

For example, if you can demonstrate that a patient sample is reacting at X-strength with a single dose example(s) of a cell(s) ("heterozygous cell") with the expression of the particular antigen, and you perform a serologic crossmatch by a method that antibody is known to react, and your policies and procedures specify this as the method used to select units that do not contain the corresponding antigen, then you have met the intent of the standard. This process can save both time and $$ without compromising patient safety---and, Yes, I have used this method/policy/procedure for years, met inspection criteria/assessments, saw no adverse patient outcomes with multiply transfused patients (and therefore was always able to sleep soundly at night related to this process.)

The reagent antisera (licensed or unlicensed) become a necessary tool when the patient antibody is no longer detectable, is weakly reacting and may not detect all expressions of the antigen, or is of insufficient quantity to test the large number of units which may be necessary to identify one lacking the corresponding antigen. I could never understand why some could demonstrate a 2-4+ antibody reactivity in the patient's serum but feel obligated to test the unit with a reagent antisera that might react 1+ at best with even a "homozygous" cell....

[L106]

I agree with JPCroke's comments. If I'm dealing with a patient who has an antibody, I may use his plasma to crossmatch 20 donor units, then use good commercial antisera to confirm the antigen typing on the donor units. I did not turn into a "manufacturer" because I was using the patient's plasma as a "tool" to find appropriate donor units in an economical way. (Also, I don't report out the patient's incompatible crossmatches in our computer system.) I view using some other patient's plasma to be a similar "tool."

I understand some of the other posters' point of not running controls. It's a matter of personal preference and factors such as the antibody plasma's strength and age, etc.

Donna

[Skinrash]

I can't thank everyone enough for their ideas and I'm glad that I wasn't off beat on my suggestions for my organization. I'm always looking for good suggestions on how to lower cost and increase efficiencies. Continuing with this topic then, My next question is how then does everyone label "screened, but not officially screened units" of their antigen typing. I was thinking if I got "unconfirmed" antigen negative labels for the typed units, that could assist with selecting units for the shifts following mine should the patient require additional units after I screened several. I'm curious how everyone else handles this in their processes? Secondly, I just want to make sure that I'm thinking correctly. When using a patient "screening plasma" would I simply treat it as a crossmatch and perform the testing through AHG phase or simply though the phase at which the antibody best reacts? If screening with GEL then, it would it be more appropriate to use the AHG phase using IgG cards, or should I screen using Buffer cards? Any help here is appreciated.

Everyone on here is awsome, keep it coming!

[Eagle Eye]

We use gel and if I decide to use pt's plasma to screen units, we use IgG gel cards to do crossmatch.

If you are using Gel, you might want to validate antigen typing by gel using traditional anti-sera as gel requires only 25microL of anti-sera as oppose to 1 or 2 drops for tube. All my antiglobulin antisera we use gel for donor screening and then we confirm negatives by tube.

[Mary**]

I would be interested in the details of your procedure for using commerical antiglobulin antisera in gel.

[Joanne P. Scannell]

I agree! If it's a false negative, then the typing with the reagent antisera will show that. This preliminary screening is not reportable.

If the saved serum/plasma was going to be used as the 'antigen testing', eg. an antibody unavailable as a reagent, then yes, controls would be necessary.

[Joanne P. Scannell]

I can't thank everyone enough for their ideas and I'm glad that I wasn't off beat on my suggestions for my organization. I'm always looking for good suggestions on how to lower cost and increase efficiencies. Continuing with this topic then, My next question is how then does everyone label "screened, but not officially screened units" of their antigen typing. I was thinking if I got "unconfirmed" antigen negative labels for the typed units, that could assist with selecting units for the shifts following mine should the patient require additional units after I screened several. I'm curious how everyone else handles this in their processes? Secondly, I just want to make sure that I'm thinking correctly. When using a patient "screening plasma" would I simply treat it as a crossmatch and perform the testing through AHG phase or simply though the phase at which the antibody best reacts? If screening with GEL then, it would it be more appropriate to use the AHG phase using IgG cards, or should I screen using Buffer cards? Any help here is appreciated.

Everyone on here is awsome, keep it coming!

Q1. Re: Labeling these 'prescreened' units. We are using patient plasma for prescreening more and more now that these reagent costs have gone so high. This raises a few questions: 1. Labeling: I plan to make a label that says something like 'Prescreened, Presume Negative/Positive for xxx' ... design it on your PC and print it on blank labels (Avery, Staples, etc.). 2. Information in the computer. It would be very helpful to have these units flagged in the BB IS so that they cannot be used for any patient will this antibody, etc. If they are testing positive with the 'preliminary' screen, a code for example, 'Presumed c-Pos', could be entered and the parameters set up in the system to not allow allocation of this unit to patients with Anti-c. 3. Charges: There is a CPT Code for screening using patient serum. I'm not at work right now so I can't look it up. I plan to use that when we use patient serum other than the intended recipient. If we are using the recipient's plasma, then it's a full crossmatch. And yes, we put that into our computer system (ie. allocate it). It should still be tagged for future reference/specimens since the computer cannot carry the incompatibility across for the patient.

Gel ... I suggest the IgG cards ...

[PammyDQ]

. Charges: There is a CPT Code for screening using patient serum. I'm not at work right now so I can't look it up. I plan to use that when we use patient serum other than the intended recipient.

I have the 2009 CPT codebook handy:

CPT code 86904 "antigen screening for compatible unit using patient serum, per unit screened"

Does this mean THE patient serum (then it's a crossmatch, not a screening?) or does this validate our practice of using another patient's serum for screening?

Tthis leads me to another question:

Does anybody charge the patient for units screened yet found positive/incompatible/unacceptable?

Anyplace I've ever worked we were told we can only charge for the same number of units ordered, even if you have to crossmatch/antigen type/etc many units more.

I have many other CPT questions but that will have to wait for another tme!

[Eagle Eye]

86904 is ---if you are using patient's own serum to screen units.

[ovrwkd]

Wow, I did not expect backlash to a comment! The respondents obviously have tools in place at their facilities to do it well.

There are facilities out there who have incomplete practices when it comes to storing screening materials and using them. Unfortunately there are multitudes of faciliteis who take gereralist staff with little experience and shove them into a Blood Bank.

[OPUS104]

Guys.... I almost didnt put this in, because I really hate getting involved with these potential arguments. Having said that, take this or leave it. AABB Tech Manual says "Whenever possible, red cells units selected for transfusion to a patient with a potentially clinically significant antibody should be tested and found to be negative for the appropriate antigen." It says to save cost "units can first be tested with the patient's serum. The absence of antigen, in nonreactive units, can then be confirmed with the commercial reagent." It then lists very specific criteria to use patient serum to screen cells at a later date. It does list some Abs that typing of units MAY not be necessary and the patient's serum can be used.... but these are like M,N,P1...and so on. I dont see how routinely not screening units with commonly availble commercial antisera can be acceptable. We use donor/patient serum to first screen quite often (following the criteria stated in the AABB Tech Man). We also use it to label as "unlicensed antisera" units screened with patient/donor for rare ones like Lua. (we just froze a patient's serum today for Lua as a matter of fact)

I am not trying to step on anyones toes here...but I believe the AABB is pretty clear when they say basically, whenever possible units should be tested with licensed antisera.

Hope this helps instead of stirring up trouble.

Edited April 2, 2009 by OPUS104

[Malcolm Needs ☆]

I'm afraid that I have come to the party a bit late, but that having been said, I think that it may well be worthwhile saying the following.

In the Laboratory at NHSBT-Tooting Centre, London, where I am the Reference Service Manager, we have run a screening programme to detect rare donors for well over 25 years. We use, mainly, human derived antisera for this, although we now have access to some monoclonal antibodies directed against high incidence antigens. During this time, we have screened, quite literally hundreds of thousands of donors for the presence or, more interestingly, the absence of such antigens as U, Lub, k, Kpb, Jsb, Coa, I, Vel, Lan, P+P1+Pk and Yta (to name but a few. For the last 10 years, we have kept accurate figures, and have performed 1, 514, 436 tests and found 2, 025 rare donors as a consequence (including 724 K+k- donors, 32 Kp(a+b-) donors, 86 Lu(a-b-) donors, 54 Co(a-b+) donors, 51 Vel- donors and 19 Yt(a-b+) donors).

In order to use the human derived antisera efficiently, usually obtained from a full donation from an "ex-patient", we perform titrations to find the end point, take the dilution back a couple of steps, and then use this dilution to screen (for example, we use our human derived anti-Lan at a dilution of 1 in 100, and have discovered 9 Lan- donors during this time).

We do use positive and negative controls, but, in our case, I'm not sure why we need the positive control, because if the antisera had stopped working, we would soon know! Every donor would be Vel-!

After we have done our screening, we then either test the donor's blood with accredited antisera "in house", or send a sample to the International Blood Group Reference Laboratory at NHSBT-Filton Centre, Bristol, for confirmation.

Our screening programme seems to me just to be somewhat larger version of what has been suggested by Skinrash, and I would agree with most of the answers posted that there is nothing wrong with this approach. It is cheap and it is effective.

I also agree wholeheartedly with those that have said that you do not become a manufacturer. You are checking your results with accredeted antisera after your screen. You are not relying on the original results.

I say good luck to you, and there should be encouragement for this kind of enterprise.

[LISA140]

when we order blood our area blood center sends a tracking sheet with the units. it will list the units and will list any known antigen statuses of those donors. the antigen results come from not only the blood center but area hospitals that have tested that donor before. now when that donor comes in again those antigens will print on the tracking sheet even though it is a different unit. it comes in handy to narrow down your search. you can also request the blood center to find you units that would be compatible for the antibodies found.

[SMW]

To OPUS104 and others.....

Please remember that the AABB Technical Manual is a textbook and is NOT the rules and regulations of the association. The Tech Manual even states that there are many ways to an end and the Standards are the final authority. Although a reputable text which undergoes a thorough editorial review process and may be used as one reference source when developing your processes, just because the author of a chapter iincludes a statement that something "should" be done a particular way, does not make it a requirement and there are other acceptable approaches to meet the intent of the Standards (which is the regulation and in some states considered the "law"). In the particular situation you quoted, the words "should" or 'must" were not used but rather the much less prescriptive "can then be confirmed".--which essentially just provides an example of one approach to the scenario.

[Mabel Adams]

The most current interpretation I have heard of CPT code rules for antigen typing is that you can bill for all units tested, both positive and negative--illogically, you cannot bill for more than one antigen on each unit. So, if you screen 20 units for c and find 3, then screen those 3 for E and all 3 are negative and you needed 2 units, you can charge for 20 antigen typings. Actually, it doesn't matter a whit how many you find or need, just how many different units you test. In most computer systems, these typing results aren't saved in batches so neither you nor anyone else would have much luck trying to determine after the fact how many units you tested and found positive.

You also can't bill a second patient if you already charged the first one.

[ovrwkd]

OK, OK, I take it back:) PLEASE.

My comment about manufacturing was meant from my observational stand point! of seeing poorly labeled containers and no "directions" for use in some facilities. There are many roads to a city. The hope is that you follow good practices and guidlines to get there.