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Blood group discrepancy Ortho vision analyzer


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Hey fellow PathlabTalkers,

                                             Enamul here from Australia. We have had situations with our Ortho Vision analyzer that O positive patients with very recent transfusions with Emergency O negative units have appeared as O NEG on the Ortho cards using the Vision analyzer. However, upon repeating the group and reverse using the ortho group cards manually they appeared as O positive. Now our theory is the transfusing O neg red cells are heavier and settle at the bottom after centrifugation and the Vision analyzer probe goes at the bottom to suck up the cells. However, doing it manually the lab tech usually take cells from the top. Do you guys have any article or have you experienced something. If you have please share.

Many thanks,

Enamul.

 

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Were these patients who 'changed' to Rh Negative massively transfused?  My experience with ProVue is that Rh Positive patients receiving as few as a single Rh Negative transfusion were graded by ProVue and visually confirmed by user as "dual population" in the anti-D tube of the gel card.

Edited by Dansket
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Hi Enamul, 

This is a known "Limitation" of the Vision Analyzer stated in the Operator's Manual-I've added the statement below.

"When a sample is collected from a recently transfused patient, the potential exists for the transfused red cells to concentrate after centrifugation at the bottom of the sample tube below their autologous cells. The probe aspirates from the bottom of the tube where the transfused cells generally concentrate which may lead to an unexpected result."

We actually have this statement in our SOP as it can be very confusing!

~Ann in CA

 

 

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Would you call that a limitation of the automat?  Personally I would not  - any more than saying that sampling from the top of the tube is a limitation of manual sampling.  It implies that there is a problem  and it lies with the automat - when in fact it's a simple manifestation of a biological property of red cells

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On 8/1/2018 at 6:00 AM, Ann in CA said:

Hi Enamul, 

This is a known "Limitation" of the Vision Analyzer stated in the Operator's Manual-I've added the statement below.

"When a sample is collected from a recently transfused patient, the potential exists for the transfused red cells to concentrate after centrifugation at the bottom of the sample tube below their autologous cells. The probe aspirates from the bottom of the tube where the transfused cells generally concentrate which may lead to an unexpected result."

We actually have this statement in our SOP as it can be very confusing!

~Ann in CA

 

 

Dear Anne many many thanks for the excellent reply. One of the blood bank gurus in Australia visited our lab and gave us an article regarding this. However, someone was on a cleaning spree and we lost it. I have to give a talk about this in a weeks time but I don't have a good journal or research paper or ortho operations manual or troubleshooting tips to back things up. However, I have great answers from yourself and others to back me up.

Edited by Enamul Haque
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On 8/1/2018 at 6:00 AM, Ann in CA said:

Hi Enamul, 

This is a known "Limitation" of the Vision Analyzer stated in the Operator's Manual-I've added the statement below.

"When a sample is collected from a recently transfused patient, the potential exists for the transfused red cells to concentrate after centrifugation at the bottom of the sample tube below their autologous cells. The probe aspirates from the bottom of the tube where the transfused cells generally concentrate which may lead to an unexpected result."

We actually have this statement in our SOP as it can be very confusing!

~Ann in CA

 

 

 

On 8/1/2018 at 6:00 AM, Ann in CA said:

Hi Enamul, 

This is a known "Limitation" of the Vision Analyzer stated in the Operator's Manual-I've added the statement below.

"When a sample is collected from a recently transfused patient, the potential exists for the transfused red cells to concentrate after centrifugation at the bottom of the sample tube below their autologous cells. The probe aspirates from the bottom of the tube where the transfused cells generally concentrate which may lead to an unexpected result."

We actually have this statement in our SOP as it can be very confusing!

~Ann in CA

 

 

Dear Ann, how does your lab react when they have a situation like this? Do they do the card manually and report the manual result like I did?

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On ‎8‎/‎4‎/‎2018 at 7:12 AM, galvania said:

The manual result is no more accurate than the result obtained on the analyser.  Personally I would report as unable to interpret due to mixed field post transfusion

This approach becomes very problematic when dual-population (mixed-field agglutination) is observed in ABO/Rh typing in a highly computerized transfusion service.  Do you segregate these patients to a manual system on paper or other type of non-standard handling or do you mainstream the patient in the computer system?

I prefer to mainstream these situations so that staff are not forced to rarely used manual systems.  One of the main tenets that I taught staff was 'to record what you see, not what you think it should be'.  So I designed the computer system to make this possible, without exception. For example, if you see dual-population in gel test, that is what you enter into the computer (there are results mnemonics 4+m versus 4+ to differentiate dual-population from uncomplicated agglutination).  

The computer is configured to reflex additional tests to the sample which prompt user with additional information and questions.  If there is a blood type on file (done prior to transfusion) and there are recent  ABO/Rh non-identical transfusions, computer will calculate blood type as Rh Positive when Rh Negative red cells are transfused to an Rh Positive recipient that resulted in the observation of dual-population in the anti-D tube of gel card of a post-transfusion blood sample. That's one heck of a run-on sentence.

The same thing will occur if a non-group O recipient is transfused with group O red cells.

Your computer system may/may not be able to do this.

Edited by Dansket
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