Anti-D Testing Mystery

[Auntie-D]

Maybe it is just too early in the morning and I haven't had enough coffee, but I am not understanding what you're trying to accomplish here. What do you mean by

"lab generated" wrong blood in tube and how does spinning the sample twice help prevent that?

 

If you (accidentally) pick up the wrong sample and take sample it for the forward and the back group, there is no opportunity to identify you have done this (it shouldn't happen, but it can). If you sample the tube, respin, then take your second sample, if you have inadvertently selected the wrong patient you will have a discrepancy between the forward and the reverse groups if there is an ABO incompatibility.

[Teristella]

If you (accidentally) pick up the wrong sample and take sample it for the forward and the back group, there is no opportunity to identify you have done this (it shouldn't happen, but it can). If you sample the tube, respin, then take your second sample, if you have inadvertently selected the wrong patient you will have a discrepancy between the forward and the reverse groups if there is an ABO incompatibility.

 

If you have the wrong sample the first time, wouldn't you have the wrong sample the second time as well? I don't really see how this helps. We shouldn't be doing blood typing on more than one sample at a time.

 

If you did pick up two samples, what if they were both group O or group A? Really common, and you would never know you'd picked up two samples. I'd much prefer relying on a double or triple check of the label on the tube and match with the requisition I'm working on. Maybe I am still missing something!

[Auntie-D]

If you have the wrong sample the first time, wouldn't you have the wrong sample the second time as well? I don't really see how this helps. We shouldn't be doing blood typing on more than one sample at a time.

 

If you did pick up two samples, what if they were both group O or group A? Really common, and you would never know you'd picked up two samples. I'd much prefer relying on a double or triple check of the label on the tube and match with the requisition I'm working on. Maybe I am still missing something!

 

If they are the same group ABO incompatibility isn't an issue. In an ideal world only one sample would be processed at a time, but where labs are still relying on manual technology for all testing, samples get batched (as used to happen in the 'olden days'). Not sure what CAP regulations are but the guidelines in the UK state the forward and reverse groups must be from separate aliquots.

[goodchild]

Again - please don't do this. Forward and reverse groups should be off two separate aliquots to reduce the risk of lab generated WBIT (if the wrong patient is accidentally selected there will be a descrepancy between the forward and reverse groups if there is an ABO incompatibility).

 

There are two 'correct' approaches (IMO and also has been policy in all the labs I have worked) 

 

1 - Do your forward group on whole blood with half the amount of dilutent (not ideal for patients with a low haematocrit but useful in emergency situations - though I have never seen a weak forward group due to prozone effect), then spin the sample and do the reverse group.

 

2 - spin the sample and set up your reverse group, then spin the sample again and set up your forward group. The 'waiting' time whilst the sample is respinning is a mini incubation period and will lessen the chance of you getting really weak back groups.

 

The chances are you aren't going to kill a patient due to ABO incompatibility (assuming they have a historic group), but what you could do is delay the provision of blood by crossmatching the wrong group and having to start again. But then you can't guarantee an AGH crossmatch to pick up ABO incompatibility...

 

Do other labs really do this? I've never heard of it and my initial reaction is one of confusion and opposition. Is this more common in UK/Europe and the US is behind the times?

[Teristella]

If they are the same group ABO incompatibility isn't an issue. In an ideal world only one sample would be processed at a time, but where labs are still relying on manual technology for all testing, samples get batched (as used to happen in the 'olden days'). Not sure what CAP regulations are but the guidelines in the UK state the forward and reverse groups must be from separate aliquots.

When I say we type one sample at a time, I mean from start to finish (edit: i.e. set up everything, drop patient cells, spin, read, result, move to next patient). Our sister hospital still does all manual testing and we use manual testing quite often as well. I've got no problem batching up to four samples at a time for a screen, setting up tubes for the typing and all that -- I drop all my reagents at once but I will only have one patient suspension active at a time, drop the cells and complete the typing before moving on to another patient.

 

I'm not sure what you mean by "ABO incompatibility isn't an issue" because isn't the more important issue the fact that you have the wrong patient's sample in your hand? You wouldn't catch it -- what if you'd dropped a manual screen with the plasma from it thinking it was a different patient?

Edited November 24, 2015 by Teristella

[Auntie-D]

Do other labs really do this? I've never heard of it and my initial reaction is one of confusion and opposition. Is this more common in UK/Europe and the US is behind the times?

 

 

Why are you opposed to the idea? It's effectively a serological double check that you have the right patient.

 

Very very few labs do routine manual testing now - almost every lab uses analysers. Some of the very small remote labs however do not have automation and may do 20-30 manual groups and screens a day.

 

I cannot find the direct reference and it is frustrating me... There is a reference to forward and reverse groups being separated to remove risk of errors (effectively two aliquots)

 

''4.5.4.

Where manual systems are used, the risk of error can be minimised by separating the procedure into distinct tasks and, wherever possible, using different members of staff to perform each task. Suggested options for achieving this are:

1. Separating the documentation of reaction patterns from the final interpretation.
2. Separating the interpretation and documentation of the forward and reverse groups.''

There is definitely a reference somewhere though lol

 

When I say we type one sample at a time, I mean from start to finish (edit: i.e. set up everything, drop patient cells, spin, read, result, move to next patient). Our sister hospital still does all manual testing and we use manual testing quite often as well. I've got no problem batching up to four samples at a time for a screen, setting up tubes for the typing and all that -- I drop all my reagents at once but I will only have one patient suspension active at a time, drop the cells and complete the typing before moving on to another patient.

 

I'm not sure what you mean by "ABO incompatibility isn't an issue" because isn't the more important issue the fact that you have the wrong patient's sample in your hand? You wouldn't catch it -- what if you'd dropped a manual screen with the plasma from it thinking it was a different patient?

 

But if you accidentally pick up the wrong sample? How would you know?

 

Even if you mix up two samples and one has antibodies, you are not going to (probably) get an immediate and life threatening transfusion reaction - for the wrong ABO you would. Hence why we still do immmediate spin crossmatches when crossmatching in gel.

[Auntie-D]

Do other labs really do this? I've never heard of it and my initial reaction is one of confusion and opposition. Is this more common in UK/Europe and the US is behind the times?

 

 

Why are you opposed to the idea? It's effectively a serological double check that you have the right patient.

 

Very very few labs do routine manual testing now - almost every lab uses analysers. Some of the very small remote labs however do not have automation and may do 20-30 manual groups and screens a day.

 

I cannot find the direct reference and it is frustrating me... There is a reference to forward and reverse groups being separated to remove risk of errors (effectively two aliquots)

 

''4.5.4.

Where manual systems are used, the risk of error can be minimised by separating the procedure into distinct tasks and, wherever possible, using different members of staff to perform each task. Suggested options for achieving this are:

1. Separating the documentation of reaction patterns from the final interpretation.
2. Separating the interpretation and documentation of the forward and reverse groups.''

There is definitely a reference somewhere though lol

 

When I say we type one sample at a time, I mean from start to finish (edit: i.e. set up everything, drop patient cells, spin, read, result, move to next patient). Our sister hospital still does all manual testing and we use manual testing quite often as well. I've got no problem batching up to four samples at a time for a screen, setting up tubes for the typing and all that -- I drop all my reagents at once but I will only have one patient suspension active at a time, drop the cells and complete the typing before moving on to another patient.

 

I'm not sure what you mean by "ABO incompatibility isn't an issue" because isn't the more important issue the fact that you have the wrong patient's sample in your hand? You wouldn't catch it -- what if you'd dropped a manual screen with the plasma from it thinking it was a different patient?

 

But if you accidentally pick up the wrong sample? How would you know?

 

Even if you mix up two samples and one has antibodies, you are not going to (probably) get an immediate and life threatening transfusion reaction - for the wrong ABO you would. Hence why we still do immmediate spin crossmatches when crossmatching in gel.

[Auntie-D]

Found it! It's talking about a rapid group/tube testing. Although it is only referring to testing when red cells are being selected, it would be good practice to extend this to all manual testing, including gel/column/card.

 

• 8.6.1.Following a rapid group, at least one the following should be performed before issuing group specific red cells:
  1. a reverse group, using a new aliquot from the patient's sample;
  2. a repeat forward group using a new aliquot from the patient's sample;
  3. a saline spin crossmatch (see 7.4).
•  

[goodchild]

 

Very very few labs do routine manual testing now - almost every lab uses analysers. Some of the very small remote labs however do not have automation and may do 20-30 manual groups and screens a day.

 

 

Maybe in the UK. I was actually polling other regional hospitals last week and after speaking with the blood bank supervisor/lab admin director for 31 institutions, 20 of them perform manual tube blood types. Three were still doing tube antibody screens.

[Auntie-D]

Maybe in the UK. I was actually polling other regional hospitals last week and after speaking with the blood bank supervisor/lab admin director for 31 institutions, 20 of them perform manual tube blood types. Three were still doing tube antibody screens.

 

I've never actually been able to get my head round this... In my first job when I started as a trainee in 1998 and the analysers were 3 years old even then.

[Dansket]

Tube testing is a 40+ year old dinosaur!  It has 10x the potential points of error compared to manual gel testing and even more compared to automated testing.

[Malcolm Needs ☆]

Have a care one and all!

 

When I started, we used small precipitin tubes for grouping, performed antiglobulin tests on tiles or in capillary tubes, then went on to the tube antiglobulin technique, then the microplate and eventually on to column agglutination techniques.  When I started, there were no monoclonal antibodies and we made our own AHG in sheep!  There were no computers, and so everything was written down on paper, rather like Bob Cratchett when working for Scrooge in Dickens' A Christmas Carol!

 

Bah, humbug!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

I will now go and lie down, before I fall asleep over my dinner from old age!!!!!!!!!!

 

       

[AMcCord]

Don't feel bad Malcolm. I still have to write everything down on paper, but I do have automation for testing .

 

Auntie-D...one of the reasons that automation has been slow to roll into US blood banks is the fact that capital purchase for the (expensive) equipment wasn't going to happen. Administration didn't blink an eye when putting it into chemistry and hematology (revenue in the black for those areas), but balked at putting it into blood bank. Blood bank is not a revenue generating area of the lab and since DRGs (mid 80s), has actually cost many/most hospitals money. Reimbursement for transfusions from Medicare and Medicaid (government) and probably many private insurers is less than the cost of providing the product. Once the manufacturers of blood bank instruments decided that they could do reagent lease (like the manufacturers of chem and hemo instruments), a lot more facilities started to aquire automation. And - let's be honest - blood bankers can be really anal creatures and pretty resistant to changes. I had to overcome mistrust in some of my techs when we started modernizing methods. If the supervisor is one of the mistrusting individuals, it ain't gonna happen.

 

P.S. - I don't think that the method described for blood typing in the UK is common practice in the US. It is certainly not required by CAP or AABB. I was trained and train my students to check the tube label every time you touch a tube. Different focus, same end.

[Auntie-D]

 

P.S. - I was trained and train my students to check the tube label every time you touch a tube. Different focus, same end.

 

Oh we have that focus too - each sample undergoes 3 (signed) checks against the form before 'filing' just for a G&S. When you add a (a manual) crossmatch to that you add a further 2 (signed) checks - one person doing the testing, another checking the interpretation, plus a check that is unsigned at every step - it is the unsigned checks that people may be lax with, that I am talking about splitting the testing to cover.

[galvania]

Well, Malcolm, Ill be there too, dreaming of precipitin tubes.  We had a system where one person read the froward group and wrote that on one side of the page - and the end of the page folded over to write the reverse group, but with the forward group results hidden - and then you could fold back the page and make sure the two results matched.  It actually worked quite well - for the limitations of the age  (I'm talking 40 years ago too, when we didn't even have calculators, never mind computers.  Anyone else remember log books  (as in logarithms)?

[Auntie-D]

Well, Malcolm, Ill be there too, dreaming of precipitin tubes.  We had a system where one person read the froward group and wrote that on one side of the page - and the end of the page folded over to write the reverse group, but with the forward group results hidden - and then you could fold back the page and make sure the two results matched.  It actually worked quite well - for the limitations of the age  (I'm talking 40 years ago too, when we didn't even have calculators, never mind computers.  Anyone else remember log books  (as in logarithms)?

 

I why don't we still do this for manual testing?

[Sandy L]

Another reason for the slow adoption of automation in the U.S. has to do with the slow process for FDA approval of automated instruments.  Alas, when Auntie D had her 3 instruments in 1989 there were really no approved instruments in the U.S suitable for Transfusion Services, just a few "Mega" sized instruments for batch typing mass quantities of samples in a donor center.  We purchased ProVues soon after they were 1st licensed, maybe around 2004, and at that time I believe perhaps the only other instrument was the ABS 1000.  Fortunately since then quite a few good instruments have been licensed in the U.S so things are looking up!

[Auntie-D]

Alas, when Auntie D had her 3 instruments in 1989 

 

Hey don't add years on me! I was only just starting secondary school in 1989

[Sandy L]

Oops, sorry about that Auntie-D.  That was 1998!  Dyslexia strikes.

[StevenB]

Tube testing has it's place.  As "older" more experienced techs retire, the art of "problem resolution" will eventually fade away as hospitals  become more reliant on automation.  Heck, I'm aware of hospitals that are unable to resolve a simple rouleaux problem due to abandoning all tube testing.  Of course, this results in delayed patient care and increased costs as they send them to us for resolution.  Perhaps that's OK though as it helps add to my job security!

 

 

[goodchild]

Perhaps that's OK though as it helps add to my job security!

 

I love it, ahahahahaha.

[Mabel Adams]

I am interested in the comment that really small remote labs in the UK do 20-30 Type and Screens a day.  The really small remote hospitals here do less than 10 per month!  The smallest one nearby is 130 miles from a bigger hospital (us).  We are the "big regional center" and we do maybe 20 per day.  It always amazes me that distances and population density are just so different in Europe than in the western US. And Alaska is even more remote!  UK 64 million people in 94,000 sq miles; Oregon 4 million people in 98,000 sq miles.

 

Another reason for the delay in taking up automation was the fact that Ortho lost their monopoly on gel in the US in 2012, immediately promised a new instrument to replace the Provue, yet did not get it approved by FDA until last August (2015) and Bio-Rad waited to come into the US market for a good 2 years after they could have and still isn't through FDA yet.  Through all of it we were told "just another 6 months", "early next year" ad nauseam. Throw the recession in there from 2008-12 and we are just now getting funding to finally get automated.

 

There are many ways to do your manual testing that can be safe with the correct safeguards built in and the best process in the world will fail if the people don't understand and therefore bypass the critical crosschecks and safety steps.

[tricore]

"It always amazes me that distances and population density are just so different in Europe than in the western US. And Alaska is even more remote! UK 64 million people in 94,000 sq miles; Oregon 4 million people in 98,000 sq miles."

 

Me too, Mabel.

New Mexico 17 people per square mile.

 

We have 12 hospitals and one commercial lab. Only 4 of the sites (all in the Albuquerqur/Rio Rancho area) have the volume to justify automation. The rest are manual gel with readers that will be interfaced with the LIS.

[Dansket]

"It always amazes me that distances and population density are just so different in Europe than in the western US. And Alaska is even more remote! UK 64 million people in 94,000 sq miles; Oregon 4 million people in 98,000 sq miles."

 

Me too, Mabel.

New Mexico 17 people per square mile.

 

We have 12 hospitals and one commercial lab. Only 4 of the sites (all in the Albuquerqur/Rio Rancho area) have the volume to justify automation. The rest are manual gel with readers that will be interfaced with the LIS.

Test volume is just one element, not the sole element,  that can be used to justify automation.  Patient safety, due to elimination of the endless variety of errors associated with manual testing, is an overwhelming reason to justify automation.  With automation you gain standardization. 

 

I'm in a small facility, less than 10 type and screens per day, with two ProVue instruments.  We have two (look in your core lab, do you backup your automated testing with manual testing)  so that we never have to resort to manual testing.

 

I believe that transfusion services that perform tube testing in 2015 do so, because that want to, not because they can't acquire automation.

Edited December 2, 2015 by Dansket

[macarton]

My first impression was either cold reagent or you picked up some fetal cells when you got your aliquot out for testing.