Trek Tech Posted December 17, 2009 Share Posted December 17, 2009 I wouldn't want to be the "rare mom" who did make Anti-D and had problems with subsequent pregnancies.....life is too precious. Link to comment Share on other sites More sharing options...
jcdayaz Posted December 18, 2009 Share Posted December 18, 2009 I wouldn't want to be the "rare mom" who did make Anti-D and had problems with subsequent pregnancies.....life is too precious.I agree Trektech2..I would not either. We are "wringing our hands" in frustration right now. Like a previous post said...we believe there are "issues" with the fetal screen kits. According to the package insert, if you see 3 rosettes per 9 low power fields you have a positive screen. If you see 2 rosettes per 9 low power fields you have a negative screen. hmmm....1 rosette difference?? Link to comment Share on other sites More sharing options...
jhodam Posted December 18, 2009 Share Posted December 18, 2009 The rosette test is a screening test. That's why it's called the fetalSCREEN from Immucor. The confirmatory test is a Kleihauer stain or flow cytometry. If you're going to get false anything from your screening test I'd hope it would be a false posive. The rosette test is quicker and easier than a K-B or flow, that's probably why it's remained in use despite the false positive problem, which I'd estimate at around 15-20% at my facility (~20% of positive FetalScreens come back below 0.3% fetal cells with KB stain). I'm not sure how that works out overall, but obviously far less than the 66% Sandra quoted as discrepant among responders on the CAP survey. It seems more likely to me the specimen was to blame than the kit, we're not all getting 66% positive FetalScreen results. Link to comment Share on other sites More sharing options...
tcoyle Posted December 29, 2009 Share Posted December 29, 2009 Does anyone have recipes for manufacturing samples for a new kit validation for the FMB screening test? Link to comment Share on other sites More sharing options...
Joseph78 Posted January 8, 2010 Share Posted January 8, 2010 Hi! I'm having problems with the Immucor Fetal Bleed Screen kit (I'm sure there's a lot of labs out there that has this problem). I was advised by Immucor to use buffered saline (pH 6.9-7.2). We are using buffered saline since I started working in this lab. I had two false positives last year that were K-B stain negative. The recent CAP survey for HBF reported that 30% of the participants reported it as "positive" (intended response = negative as specified by the vendor). 30% of false positive is not negligible. I'm planning to order reagents from Ortho. Can anyone share on where to order validation kit for FMH? I need 10 positives and 10 negatives. Thanks in advance. Link to comment Share on other sites More sharing options...
Joseph78 Posted January 8, 2010 Share Posted January 8, 2010 Does anyone have recipes for manufacturing samples for a new kit validation for the FMB screening test? Hi! Do you have the recipes for manufacturing samples for FMH? I already ordered the reagent from Ortho and I will start my validation next week. I have already 3 positive samples though. Link to comment Share on other sites More sharing options...
jcdayaz Posted January 8, 2010 Share Posted January 8, 2010 Hi! I'm having problems with the Immucor Fetal Bleed Screen kit (I'm sure there's a lot of labs out there that has this problem). I was advised by Immucor to use buffered saline (pH 6.9-7.2). We are using buffered saline since I started working in this lab. I had two false positives last year that were K-B stain negative. The recent CAP survey for HBF reported that 30% of the participants reported it as "positive" (intended response = negative as specified by the vendor). 30% of false positive is not negligible. I'm planning to order reagents from Ortho. Can anyone share on where to order validation kit for FMH? I need 10 positives and 10 negatives. Thanks in advance.Consider yourself lucky that you only had two false-positives last year!! We were seeing two per month!!!!!!!!I guess, however, it is better to get a false-positive result than a false-negative result!! Link to comment Share on other sites More sharing options...
kate murphy Posted January 8, 2010 Share Posted January 8, 2010 Okay - everybody take a deep breath now...Fetal rosetting test is based on dilute anti-D.Our bench anti-D reagents now are all monoclonal - to very specific epitopes of the D antigen. Different manufacturers have antibodies to different epitopes of the D antigen. We're seeing that many of our "D neg" moms are actually D pos when tested with another manufacturer's antisera. These patients are weak D, D variants or partial D's. The mom's I am concerned about are the partial D's, as they may make anti-D; variants and weak D's generally do not.There is nothing wrong with the kit. It's the monoclonal anti-D we use to test moms that's different. We use Immucor's kit for screening. I also would much rather have a positive screening, and a neg K-B or flow, than the other way around.So, a little sleuthing, a little logic....and Bob's your uncle. Link to comment Share on other sites More sharing options...
Joseph78 Posted January 8, 2010 Share Posted January 8, 2010 Consider yourself lucky that you only had two false-positives last year!! We were seeing two per month!!!!!!!!I guess, however, it is better to get a false-positive result than a false-negative result!!I concur. Are you planning to switch to other reagent kits? I hope that they will resolve this problem so I won't waste my time doing the validation. Link to comment Share on other sites More sharing options...
AMcCord Posted January 8, 2010 Share Posted January 8, 2010 I talked to someone in Tech Supporrt at Immucor about this problem again yesterday. He gave me a LONG list of things they have considered or are considering as the cause of the problem. Add in the variables that come in to play with all of us doing the test in whatever way we do it and you've got yourself a major headache. I was told that they are not giving up, they are not ignoring the problem. He suggested that we try washing our tests with the saline we're putting on the Echo (ie. unbuffered saline with pHix added). I'm going to do parallel testing with our normal buffered saline and see what happens. I also agree that a false-positive test beats a false negative. Link to comment Share on other sites More sharing options...
LaraT23 Posted January 8, 2010 Share Posted January 8, 2010 Just wanted you all to know that Ortho has its Fetalscreen II out on the market! I just got mine in and plan to switch to it from Immucor ASAP. What is nice is that you only have to examine 5 fields on this one, and on the first try today it worked really well. Oh, and Malcom, it is made in the UK! I was writing the procedure to day from Ortho's instructions for use and found this phrase: " Do not use any component of this kit beyond their expiry". It is like the procedure has an accent!!! Link to comment Share on other sites More sharing options...
Mary Ann Posted January 9, 2010 Share Posted January 9, 2010 1 vial of rhogam-false pos on fbs due to Mom's weak D. Link to comment Share on other sites More sharing options...
jcdayaz Posted January 9, 2010 Share Posted January 9, 2010 I concur. Are you planning to switch to other reagent kits? I hope that they will resolve this problem so I won't waste my time doing the validation. Right now we are trying to wait it out until they find a resolution. That may change.Previous post is correct. Fetal Screen Rosette test is only a "screening" test. By definition it's not as accurate as a KB stain for detecting/quantifying fetal-maternal bleed. HOWEVER, WE ARE BLOOD BANKERS AND WANT TESTS TO WORK RIGHT AND BE ACCURATE. WE ARE NOT COMFORTABLE WITH "WELL, MAYBE". That's why we are Blood Bankers!!As a matter of fact, I often wonder how our non-medical, non-blood banker friends/family put up with us!!!!!!! Link to comment Share on other sites More sharing options...
jcdayaz Posted January 9, 2010 Share Posted January 9, 2010 Okay - everybody take a deep breath now...Fetal rosetting test is based on dilute anti-D.Our bench anti-D reagents now are all monoclonal - to very specific epitopes of the D antigen. Different manufacturers have antibodies to different epitopes of the D antigen. We're seeing that many of our "D neg" moms are actually D pos when tested with another manufacturer's antisera. These patients are weak D, D variants or partial D's. The mom's I am concerned about are the partial D's, as they may make anti-D; variants and weak D's generally do not.There is nothing wrong with the kit. It's the monoclonal anti-D we use to test moms that's different. and Bob's your uncle.We do our testing in gel. It is an extremely sensitive testing method, sometimes too sensitive. Are you still doing tube-testing?? The gel method typically detects partials, mosaics, whatever. Okay...what's the "Bob's your uncle" comment about???? Sounds like a good one!:cool: Link to comment Share on other sites More sharing options...
Joseph78 Posted January 9, 2010 Share Posted January 9, 2010 Just wanted you all to know that Ortho has its Fetalscreen II out on the market! I just got mine in and plan to switch to it from Immucor ASAP. What is nice is that you only have to examine 5 fields on this one, and on the first try today it worked really well. Oh, and Malcom, it is made in the UK! I was writing the procedure to day from Ortho's instructions for use and found this phrase: " Do not use any component of this kit beyond their expiry". It is like the procedure has an accent!!!Hi Lara! I ordered the fetal screen from Ortho and it will get here next week. Did you do validation? If so, do you know I could order a validation kit? If not, what did you use for validation? Can you manufacture your own specimen? Thanks in advance. Link to comment Share on other sites More sharing options...
AMcCord Posted January 12, 2010 Share Posted January 12, 2010 "Bob's your uncle" means everything is fine or going well. Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted January 12, 2010 Share Posted January 12, 2010 "Bob's your uncle" means everything is fine or going well.How true this is I don't know, but I've heard it comes from a particular bit of nepotism that took place in the UK in 1887.The (then) very young Arthur Balfour was appointed to the important post of Secretary for Ireland by the (then) British Prime Minister, Lord Salisbury, who happened to be his uncle.Lord Salisbury's forename was Robert, and, of course, the diminutive of Robert is Bob.:D:D:D Link to comment Share on other sites More sharing options...
adiescast Posted January 12, 2010 Share Posted January 12, 2010 That is too funny...I wish Bob was my uncle! Link to comment Share on other sites More sharing options...
TimOz Posted January 12, 2010 Share Posted January 12, 2010 Sorry for coming in late but I want to comment on the first post in nthis thread from GilTphoto.the statement "The AABB Technical Manual states that the K/B procedure's accuracy is poor, and any time the K/B is questionable" is a mostly true. Australia has done a lot of work in this area and to sum it up in points:1. The K-B test is an excellent and sensitive screen for FMH IF the method is done well. It is a very poor method for quantiitation. The commonest error is the accohol used a a cell fixitive. If it is not pure, AR grade, fresh and from a well sealed container it will absord water from the air and the cell fixation and therefore the test will fail. "Grabbing a bit of ethanol from Histo" seems to be very poor practice.2. It is a very sensitive test and low power microscope objectives can be used to scan a large number of blood smear fields. It is very poor at quantitation due to the subjectivity and the variations on method, microscopy and the maths used to calculate the bleed volume.3. K-B tests can and will fail in cases of Hereditary persistence of Foetal Haemoglobin. In this case all cells will be non-eluted so it should be obvious. Foetal Thalasemias will also cause problems.4. Australian survey (RCPA IH QAP) advice is that K-B is the best screening method and if positive, quants should be done using flow cytometry. Anti-D and anti-HbF can be used depending on the situation and the foetal RhD group.I don't think anyone used foetal screen here but some labs use commercial K-B kits and some of these kits have had batch related problems and failed. Anyone who is interested can PM me and I can send a PPT of the survey results comparing methods used in Australia and NZ. Link to comment Share on other sites More sharing options...
jcdayaz Posted January 12, 2010 Share Posted January 12, 2010 That is too funny...I wish Bob was my uncle!I second this thought adiecast!!! How nice it would be to occasionally get a break that you didn't work your you-know-what off for!! Link to comment Share on other sites More sharing options...
TimOz Posted January 12, 2010 Share Posted January 12, 2010 Malcolm is correct as to the origin of the "Bob's your uncle" saying. Australians say it often probably due to the Irish connection. Just one point though. It translates to "all is OK" but it really has other subtle connotations from it's origin. It means that no matter how hopeless or unsuited you are to a task or job you will still be assigned it because you know someone influential. In common use it sort of means that no matter how badly you have done something and maybe even botched it, the outcome will stiill be fine. Link to comment Share on other sites More sharing options...
AMcCord Posted January 19, 2010 Share Posted January 19, 2010 How true this is I don't know, but I've heard it comes from a particular bit of nepotism that took place in the UK in 1887.The (then) very young Arthur Balfour was appointed to the important post of Secretary for Ireland by the (then) British Prime Minister, Lord Salisbury, who happened to be his uncle.Lord Salisbury's forename was Robert, and, of course, the diminutive of Robert is Bob.:D:D:D"Bob's your uncle" came up in conversation with a co-worker one day (yes, we have strange conversations - kind of Trivial Pursuit without the game) and we were so intrigued by it that we had to Google it and see where it came from. Your "uncle Bob", Lord Salisbury, was definitely our favorite version of the origin of the phrase. Did you know that nepotism comes from the Italian word for nephew? Link to comment Share on other sites More sharing options...
TimOz Posted January 19, 2010 Share Posted January 19, 2010 I think you mean "Nepos" from Latin rather than modern Italian. Italian and French have similar words but the etymology is older. Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted January 20, 2010 Share Posted January 20, 2010 Goodness me!I seem to have started something here.:eek::eek: Link to comment Share on other sites More sharing options...
LaraT23 Posted January 20, 2010 Share Posted January 20, 2010 I have to admit that I have never heard that term before and now after all the explanation, understand what you are meaning. Texans might use another version with "Bubba" inserted for Bob, lol. Link to comment Share on other sites More sharing options...
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