Auntie-D Posted October 2, 2015 Share Posted October 2, 2015 (edited) We have a lady who had a negative antibody screen at booking and 28 weeks (Rh pos to make things easier). She had pre induction bloods taken and came back with a 3+ reaction in cell one only but with a dual population effect. A panel was done and the IAT and enzymes were both negative. A repeat sample was taken and it reacted again on the analyser but this time 3+3+2+ reactivity. The plasma was removed from both samples and hard spun and the resulting plasma yielded negative antibody screens when done manually. The cards on the analsyer don't look like genuine agglutination - there is too clearly defined a gap between the two populations and it looks more like a 4+ reaction MF rather than a 3+ or 2+. We use Ortho and centrifuge at 1000 RCF for 5 minutes to give the correct dilution for the (awkwardly sensitive to TMC issues) analyser. Both samples we tested using the same lot of cards and cells. So my question is - what on earth is going on? Edited October 2, 2015 by Auntie-D Link to comment Share on other sites More sharing options...
Auntie-D Posted October 2, 2015 Author Share Posted October 2, 2015 Post delivery samples have now arrived and they are clean as a whistle, negative! Link to comment Share on other sites More sharing options...
Auntie-D Posted October 2, 2015 Author Share Posted October 2, 2015 Further update - both prior samples were sent to our sister hospital and came up negative. Stranger... Link to comment Share on other sites More sharing options...
galvania Posted October 2, 2015 Share Posted October 2, 2015 Fibrin?Cold ants? Did you put up a panel in the IgG cards with incubation at RT?Interference from white cells? Link to comment Share on other sites More sharing options...
Auntie-D Posted October 2, 2015 Author Share Posted October 2, 2015 (edited) Fibrin?Cold ants? Did you put up a panel in the IgG cards with incubation at RT?Interference from white cells? No to fibrin. We haven't done RT panels - with 3 samples showing different results all taken within 3 hours of each other I couldn't see the point - especially now we know that the samples are negative in our sister lab with the same technology and same batches of reagents. Plus the 3rd (post delivery) sample is negative. Also the reverse group is fine. White cell interference is unlikely as the analsyer samples at the top of the tube, well away from the buffy layer. Edited October 2, 2015 by Auntie-D Link to comment Share on other sites More sharing options...
galvania Posted October 2, 2015 Share Posted October 2, 2015 What about the wells in your cards? Any signs of dried gel? Link to comment Share on other sites More sharing options...
catchmenow51 Posted October 2, 2015 Share Posted October 2, 2015 Cold would have been my guess. The sister sample could have been shipped in a cold environment and antibody adsorbed onto cells before testing? But other than that, I got nothing.... Link to comment Share on other sites More sharing options...
Yanxia Posted October 3, 2015 Share Posted October 3, 2015 I had met specimen showed different reaction in our lab and reference lab, we guess it was because drugs. The drugs concentration in the patient's blood will reduce along with time Link to comment Share on other sites More sharing options...
Yanxia Posted October 3, 2015 Share Posted October 3, 2015 But this can not explain why the same specimen got different result in two labs Link to comment Share on other sites More sharing options...
Joanne P. Scannell Posted October 5, 2015 Share Posted October 5, 2015 Cold Antibody: Anti-M? (Gel is notorious for picking up Anti-M due to it's acidy ... so don't expect duplication with tube.) And Anti-M is so persnickity ... reacts with homozygous-only sometimes, reactive cold-only sometimes, reactive warm sometimes ... and sometimes the screening cells are all M Positive ... temperature of the plasma/gel card/room at time of testing ... etc. We find 'a lot' of Anti-M's on our prenatals ... just a thought to chase down. Link to comment Share on other sites More sharing options...
R1R2 Posted October 5, 2015 Share Posted October 5, 2015 Have you considered sample contaminated with IV fluid. Link to comment Share on other sites More sharing options...
Auntie-D Posted October 5, 2015 Author Share Posted October 5, 2015 Wouldn't an Anti-M or contamination give the same results at our sister lab though? Link to comment Share on other sites More sharing options...
galvania Posted October 6, 2015 Share Posted October 6, 2015 OK - so let's start from the beginning. What is wrong with this patient? Was the patient receiving any fluids at the time of taking the sample? what were the other results? Link to comment Share on other sites More sharing options...
Auntie-D Posted October 6, 2015 Author Share Posted October 6, 2015 Patient was in labour - 1st sample on admission, 2nd repeat and 3rd post natally. The medics claim she wasn't on any IV infusions and had gone into labour naturally, not induced. All haematology and chemistry results within normal parameters. DCT negative. Link to comment Share on other sites More sharing options...
Malcolm Needs ☆ Posted October 6, 2015 Share Posted October 6, 2015 DCT???????????????????????? Link to comment Share on other sites More sharing options...
galvania Posted October 7, 2015 Share Posted October 7, 2015 I was sort of looking for the other IH results. But I've gone back to the original posting. I am convinced that this was fibrin. Sorry, but it disappeared when you hard spun the plasma - that is screaming fibrin to me. Even if it IS an EDTA sample Link to comment Share on other sites More sharing options...
David Saikin Posted October 7, 2015 Share Posted October 7, 2015 I agree Anna - especially since it is a pregnancy specimen. EDTA is not immune to fibrin formation. That strong mf rx usually shouts anti-M to me but a strong alternative is fibrin in the specimen. Link to comment Share on other sites More sharing options...
BloodBankBlake Posted October 7, 2015 Share Posted October 7, 2015 I have seen this before, cold auto. We did an auto adsorption at 4C, and reran the sample; like yours, clean as a whistle. And I agree with catchmenow51 about the potential adsorption in transport. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now