hi everybody I wanted to go over another antibody ID example um just to kind of walk you through the process again so hopefully what you first did was printed out the blank version that had the reactions in ahg did your highlights did your cross-offs and now you're comparing notes here to see if it if mine looks like yours hopefully it does now I've I've added um a little extra something at the bottom um so remember antibody identification panels are usually not done in a vacuum without any previous testing done before it so there was always a screen that came up positive in ahg that would lead to a clinical lab scientist then needing to perform an antibody identification panel so um the at the very bottom of the screen here you see that I've pasted the screening cells reactions for you and because this is work that you have already performed when you have it available and you know usually use the same manufacturer for your screening cells and your panel cells um so like in this case you can see it lines up perfectly the antigens all match but even if they didn't you could still use your screening cells if you have any negative rows in your screening cells as an additional little bit of help with your antibody ID without having to do any extra work after the panel so here you see that I've included the screening cells at the bottom and that there is one of the two cells that was negative in ahg so we can highlight that row and include it in our cross-offs so how it worked during the most recent um assignment was I was hoping that you would sit down with your completed panel using the strategies and the steps that I have taught you and be able to look at your panel and answer the questions related to the panel so one of the questions that I frequently ask is which antigens across the top of the panel do you have circled meaning that there are no cross-offs homozygous or heterozygous in the entire column all the way down and in the case of this particular panel I've circled Big C and jka now CW and kPa do not have any cross-offs either however I am not ever immediately thinking that a low frequency antigen is to blame for us finding an antibody like this so um I don't Circle them right away what you see I've done in the CW column and the kPa column is circled the cells that have CW and kPa on them happens to be the same cell cell number one because I'm going to come back and revisit it after I get a little bit closer to complete with my my panel so if if I were to ask the question of you what antigens do you have circled on this panel you would be telling me just Big C and jka now you also see that there are some antigens that don't have any cross-offs or don't have um they're not marked off across the top row but you can see that they have a one or an H above them so in the case of Big K we do have one cross off in cell number five but we don't have a second cross off and so we need to remind ourselves that we have some unfinished business so to speak with the big k antigen then um keep going to the right and you'll see that I have a one above Louis a again because I still need one more cross off for Lewis a um big S also still has one cross off remaining um you can see down in the screening cells is where I got my homozygous cross off for S so any other cross off I can find using um selected cells will help us rule out s and then there's an H over the M antigen that even though M has three heterozygous cross-offs that is not enough to rule it out remember for most antigens you have to have one homozygous and one heterozygous cross-off to be able to rule it out so that M antigen is missing the the homozygous cross-off so you could say that the unfinished business that I have yet to complete are related to um Big K and Lewis a M and big S then you can also see that um there are some words written above a couple of the low frequency antigens on this particular panel we actually have a number of low frequency antigens including cwv JSA kPa um let's see here Lutheran a and WRA so um WRA I forgot to cross it out but it is ruled out by the rule two which states for a low frequency antigen only that if none of the panel sells and if you look down that entire column for WRA you see that none of the panel cells or the screening cells even have that antigen on them so there is no way that WRA could be an explanation for why we're seeing reactivity in ahg so you cross that out and Rule it out based on rule 2. then you can see um the V antigen follows the same pattern you can look down the entire column for V and see that none of the panel cells have the antigen so I've marked that off as rule two and then um you'll see that Lutheran a has rule one above it because in cell number three we were able to cross give a heterozygous cross-off for Lutheran a and for a low frequency antigen a single heterozygous or homozygous cross-off is Enough To Rule it out so those are some of the ones that we can automatically get rid of based on some low frequency rules there are three low frequencies that are still like not dealt with um so we've got the CW and the kPa and the JSA are three low frequency antigens that have the antigen on one or more cells you can see I've circled them CW and kPa are on cell one and JSA is on Cell six so those will likely eventually be ruled out by um the third rule for low frequencies and um so if we if if we just assume moving forward that we have for instance two antibodies present in this particular sample the two that we've circled Big C and jka we'll just assume that for right now the way we apply the rule three for low frequencies is that if an antigen is on the same cell as a low frequency antigen that is a far more likely culprit for an antibody to be directed against in this case we are suspecting that we have antibodies to jka and C which is a lot more likely scenario than having antibodies to kPa or CW or JSA so if we see that the low frequency antigen is on the same cell as the more likely antigen to which we think we have an antibody we can explain away the reactivity that we're seeing in ahg by the presence of that more likely antibody in our case potentially both antibodies jka and Big C so that explain away rule can be applied only to low frequencies so you know moving forward it's imperative you know what the low frequency antigens are and usually they're pretty obvious on the um panels and the screening cells I mean basically none of the cells will have the antigen or maybe just one of the cells will have the antigen so you know even if you're not good at memorizing things you can look at a panel and be able to pick out which ones are considered low frequency simply by the number of cells in the panel that have the antigen so um right now moving forward all you can really say is that you are suspicious that you might have as many as two antibodies present antibodies to Big C and jka you don't know that for sure yet because you have to actually do some additional work which I'm going to present us another video about that here in just a minute um but uh you're suspicious that you have jka and C antibodies you have some unfinished business to deal with regarding the antigens that you have ones and H's over so you still have some selected cells you need to choose to continue your your work ruling out Big K and Lewis a homozygous crossed off for Big M and another cross off for Big s and then we'll use the explain away rule three um to not considered that CW K kPa or JSA are our issues it is extremely extremely rare to have antibodies against a low frequency antigen so it's just not something that you automatically should be thinking as a suspicious thing all right let me pull together um the selected cells and how we strategize to figure out if we're dealing with antibodies to both jka and C or just one or the other so um I'll post another video so that these don't get too long and hold tight for just a minute