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RHD Molecular Testing

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For those of you who send samples out for RHD Molecular testing do the physician need to order this test or can lab order it to aid in the investigation of D typing? Our Ref lab performs Bioarray RHD Beadchip which is RUO. Do you report molecular testing result in HIS?

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In our lab, the required additional testing is built into our procedures - which is authorized by the pathologist.  If we have weak D results or something like an auto-anti-D in an Rh pos person we can send it out without asking for approval.  We scan the report we get back into our LIS.

I'm in Canada - so the testing is done by Canadian Blood Services at no additional cost the the hospital.

sandra

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We are not yet charging the patients, so are sending out under our pathologist's name to the Immucor DX Reference Lab.  We place the results in the history comments of the patient's computer record.  If we start charging, we will also have to scan the lab report into the pt's chart for the electronic record.

Edited by cswickard

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We do the same as AuntieS.  We have it written into our procedure that if a female of child bearing age is weak D, we send for molecular with no additional order from the physician.  This was approved by our med exec committee and is in our reflex testing protocol so we can charge the patient for it.  We scan the results into EPIC

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Thank you for the replies. We sometime send the test out if it's a female of child bearing age too. We are currently not charging for it. Since it's a Research use only test I wasn't sure how the billing works and whether or not it should be scanned into patient's chart?

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2 hours ago, sunshine said:

Thank you for the replies. We sometime send the test out if it's a female of child bearing age too. We are currently not charging for it. Since it's a Research use only test I wasn't sure how the billing works and whether or not it should be scanned into patient's chart?

Sorry, but can I just point out that you should be sending out the tests if the patient is a female of child bearing POTENTIAL, rather than child bearing age.  If the female is four (for example), she is not likely to be of child bearing age, but she will be one day, and if she is an individual who has a Partial D type who can produce an anti-D, she deserves as much care as does a female of, for example, 25 years.

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Thank you for pointing that out. We are Transfusion lab. Today we call anyone with  <=1+ Rh tube typing as Rh Neg.

 

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3 hours ago, sunshine said:

Today we call anyone with  <=1+ Rh tube typing as Rh Neg.

 

Does the manufacturer's directions for your Rh tube typing reagent allow for interpreting a positive test result as Rh Neg?  If not, how would you defend your policy (that is contrary to the manufacturer's directions) to a knowledgeable inspector?

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1 hour ago, Dansket said:

Does the manufacturer's directions for your Rh tube typing reagent allow for interpreting a positive test result as Rh Neg?  If not, how would you defend your policy (that is contrary to the manufacturer's directions) to a knowledgeable inspector?

I think that this would very much depend upon whether the red cells are from a donor or a recipient.  In the UK, for example, the anti-D reagents used in hospital laboratories, where they are testing (almost exclusively) patients, are designed not to detect Partial DVI, whereas those used in the NHSBT for donors and, to a certain extent, some of the reagents used in the Reference Laboratories are designed specifically to detect Partial DVI.  This means that an individual could be designated as D Positive as a donor, and D Negative as a recipient.  This would take a bit of explaining to the individual involved and, very often, to the doctor looking after the individual if they were not too familiar with transfusion.

I would be amazed if manufacturers would make such a direction, because it is unlikely that all anti-D reagents are guaranteed to detect ALL partial D types (notably the DEL types) but WILL detect ALL Partial DIII type individuals, which can, and often do produce an allo-anti-D.

I would be very confident to defend my own policy to a knowledgeable inspector, although I HOPE such an inspector would be knowledgeable enough NOT to ask about this in the first place!  The attached diagram is of Partial DVI Type 1 (copied from a diagram by Geoff Daniels).

Partial DVI Type 1.pptx

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21 hours ago, Dansket said:

Does the manufacturer's directions for your Rh tube typing reagent allow for interpreting a positive test result as Rh Neg?  If not, how would you defend your policy (that is contrary to the manufacturer's directions) to a knowledgeable inspector?

The interpretation of patient anti-D results reacting </= 1+ is consistent w/ CAP and AABB guidelines. So there shouldn't be an issue w/ an inspector. If there was, I would contest the citation.

And yes, there are individuals who are Rh positive donors, but Rh negative patients.

Edited by AMcCord

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3 hours ago, AMcCord said:

The interpretation of patient anti-D results reacting </= 1+ is consistent w/ CAP and AABB guidelines. .

Your statement implies that users do not have to follow the manufacturer's direction insert if they are inspected by CAP and/or AABB.  May a transfusion service that is not inspected by AABB/CAP also elect to not follow manufacturer's insert?

Please provide the CAP Transfusion Medicine Checklist number from the 2018 edition that references your statement.  I am not familiar with "AABB guidelines".  Are you referring to the Standards or the Technical Manual?

Edited by Dansket
added "also" to sentence

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23 hours ago, Malcolm Needs said:

I would be amazed if manufacturers would make such a direction, because it is unlikely that all anti-D reagents are guaranteed to detect ALL partial D types (notably the DEL types) but WILL detect ALL Partial DIII type individuals, which can, and often do produce an allo-anti-D.

Partial DVI Type 1.pptx 84.86 kB · 9 downloads

For example, Ortho-Clinical Diagnostics produces three Anti-D products in the United States (see attached files).  Instructions for Use of each antiserum state that the presence of agglutination is a positive test result and is interpreted as Rh Positive when the Rh Control test is negative.

I get that the scientific community is not 'in-sync' with the regulatory or manufacturing communities, but how does one justify not following the Instructions For Use, specifically the interpretation of test results, for a product approved and licensed by the FDA?

It is curious to me that veteran posters in this forum have stated consistently that one must follow manufacturer's directions, but now say user does not have to follow the Anti-D direction insert.

e631200462_EN.pdf e631207615_EN.pdf MTS-ABDMR_J32851_3_EN (1).pdf

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2 hours ago, Dansket said:

For example, Ortho-Clinical Diagnostics produces three Anti-D products in the United States (see attached files).  Instructions for Use of each antiserum state that the presence of agglutination is a positive test result and is interpreted as Rh Positive when the Rh Control test is negative.

I get that the scientific community is not 'in-sync' with the regulatory or manufacturing communities, but how does one justify not following the Instructions For Use, specifically the interpretation of test results, for a product approved and licensed by the FDA?

It is curious to me that veteran posters in this forum have stated consistently that one must follow manufacturer's directions, but now say user does not have to follow the Anti-D direction insert.

e631200462_EN.pdf 66.16 kB · 2 downloads e631207615_EN.pdf 62.64 kB · 1 download MTS-ABDMR_J32851_3_EN (1).pdf 468.34 kB · 1 download

I don't know what happened, but I tried to answer three times on here, and each time it locked up, so Dansket, I have written a Word document in reply, and attach it should you want to read it.

PathLabTalk Answer.docx

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On 3/21/2019 at 7:59 AM, Dansket said:

Thank you for pointing that out. We are Transfusion lab. Today we call anyone with  <=1+ Rh tube typing as Rh Neg.

Malcolm,

With all due respect, you have completely misinterpreted my original response to sunshine's post quoted above.  As sunshine stated, he/she is a Transfusion lab. So his/her post refers only to recipient testing as does my response. I do not disagree with any of your statements regarding Rh typing of donors, but they are irrelevant to my response to sunshine's post .

Secondly, sunshine states that he/she interprets a 1+ test result with Rh tube typing as Rh Neg. It is this statement to which my post is directed.  If sunshine is using ORTHO Anti-D, either liquid or gel (and I don't know if he/she is using ORTHO), he/she is not following the manufacturer's Instructions For Use.

Not following direction insert (for FDA licensed antisera) is not justified by criticizing the manufacturer, or referencing some guidelines, or citing scientific literature.  Maybe this is not an issue for you in the UK, but it is in the US.

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To amaze you and challenge your statement, "I would be amazed if manufacturers would make such a direction".  I provided three examples of Anti-D typing reagents that did give such direction.

For patient testing, ORTHO requires an interpretation of Rh Positive (assuming a negative control test) if a positive test result (presence of agglutination) is demonstrated with any of their Anti-D typing antisera (liquid or Gel).

For your further amazement and amusement, please read the following from CAP announcing 2018 revisions to the Transfusion Medicine Checklist, "Also clarified in the 2018 checklist is that the use of molecular-based screening assays alone for ABO and Rh(D) blood type assignment is unacceptable for transfusion or transplantation. “We still do not know completely everything about ABO and Rh molecular typing,” Dr. Gandhi says, which is why TRM.40550, “Forward/Reverse Typing,” now says an FDA-cleared or -approved serological method must be used. ABO/Rh typing for transplant or transfusion has to be done “by an FDA-approved method, and right now that’s only serology,” Dr. Gandhi says.

“We use molecular-based testing for a lot of blood bank phenotyping now,” Dr. Park says,

“but it is not acceptable and it’s just not the right testing and methodology for ABO and Rh.” ABO and Rh typing by molecular methods is complicated and not without risk, she says, adding, “Serology is very simple, so go with the simple one that works well.”

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Sunshine I am curious as if a patient has an anti-D result of 1+ or less you enter them as Rh negative, why do you then send out for RHD Molecular testing and what do you use the results for. 

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We are starting to phase in the molecular testing for discrepant RHD testing.  (Rh neg/Weak D pos and/or weak reactions with standard FDA approved Anti-D reagents (- which may be what Sunshine is doing - only we put them in the computer as Weak D pos)).  We are going to be taking the recommendations of the 2015 workgroup ("time to phase in RHD genotyping....)" and getting a more definitive answer for ourselves and our OB doctors that is safe for our patients and less of a strain on our Rh neg blood supply. 

Can anyone share a procedure with some of the correct technical terms to help us get through this morass?  AuntiS? or JoyG? - seems like you already have it working.  We may go a head and build it in the computer reflex testing too, but that will be for another day since Meditech may take some convincing!?

 

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On 3/20/2019 at 4:17 AM, sunshine said:

For those of you who send samples out for RHD Molecular testing do the physician need to order this test or can lab order it to aid in the investigation of D typing? Our Ref lab performs Bioarray RHD Beadchip which is RUO. Do you report molecular testing result in HIS?

In this reference laboratory, either reference lab or submitting hospital decide whether to test RHD molecular or not. The RHD geno here is not by HEA beadchip but by other in-house methods. For the purpose of simplicity for our transfusion services staff, we translated the RHD results in terms of potential to produce anti-D and code them in as Antigens in our LIS. If RhD negative blood is warranted, we post D* as antibody (communicated to staffs as "give D- but patient has not make anti-D), so that LIS will stop us from issuing D+ units.

For patients with weak D type1, type2 or type 3, we used the codes WKD1, WKD2, WKD3 as antigens.

For patients with RHD variants that has potential to make anti-D. we used the code WKDV as antigens. We also put in predicted RHD variant in patient's comment (for example RHD*DAR or weakD 4.2.1 etc) Also post D* in antibody profile so LIS will stop the tech from issuing D+ units. 

For patients with RHD variant in heterozygote expression but also has normal D gene- we do not post anything in antigen or antibody profile. However we free text the predict allele in the patient's comment. For example, "Genomic RHD testing indicates a normal D allele with RHD* DAR1.2. (I suppose posting other terminology. like weakD 4.2.2 instead of allele name will be fine too) 

Hope it is helpful

Edited by dothandar

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dothandar, an excellent post if I may say so (although I don't absolutely agree 100% with the terminology you use).

I agree that Weak D Types 1, 2 and 3 are to be regarded as D Positive, if the following two papers are to be followed - which I think they should (Daniels G.  Variants of RhD – current testing and clinical consequences.  British Journal of Haematology 2013; 161: 461-470 and Sandler SG, Flegel WA, Westhoff CM, Denomme GA, Delaney M, Keller MA, Johnson ST, Katz L, Queenan JT, Vassallo RR, Simon CD.  It’s time to phase in RHD genotyping for patients with a serological weak D phenotype.  Transfusion 2015; 55: 680-689).  However, as individuals of all three weak D types have, very, very rarely produced allo-anti-D (see Daniels G.  Human Blood Groups.  3rd edition, 2013, Wiley-Blackwell), they could all be put into your computer as WKDV.

Sorry, I am mucking you about - it really is an excellent post!

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2 hours ago, Malcolm Needs said:

dothandar, an excellent post if I may say so (although I don't absolutely agree 100% with the terminology you use).

I agree that Weak D Types 1, 2 and 3 are to be regarded as D Positive, if the following two papers are to be followed - which I think they should (Daniels G.  Variants of RhD – current testing and clinical consequences.  British Journal of Haematology 2013; 161: 461-470 and Sandler SG, Flegel WA, Westhoff CM, Denomme GA, Delaney M, Keller MA, Johnson ST, Katz L, Queenan JT, Vassallo RR, Simon CD.  It’s time to phase in RHD genotyping for patients with a serological weak D phenotype.  Transfusion 2015; 55: 680-689).  However, as individuals of all three weak D types have, very, very rarely produced allo-anti-D (see Daniels G.  Human Blood Groups.  3rd edition, 2013, Wiley-Blackwell), they could all be put into your computer as WKDV.

Sorry, I am mucking you about - it really is an excellent post!

I completely agree with you with Weak D Type 1, 2 and 3. I think there are more than 3 cases of allo-anti-D so far. I am questioning the approach to give D+ blood to these patients as well (personally opinion, I know it may be an ongoing debate). Let me look up the case reports of anti-D in Weak D Type 1,2,or 3 to get back to you. I have a feeling that 3 is a bit too little. 

My other question is whether to look for other D variants when Weak D type 1,2,or 3 were detected in individuals of African origin as they may have other additional variants that can potentially lead to production of anti-D. 

I am very glad that you brought up these cases of anti-D in Weak D type 1,2 or 3. It truely is a great opportunity for further discussion. 

I admit that I can be neglectful when it comes to terminologies (which my mentors will not be happy about). I would really appreciate it if you would take the time to point our my terminology errors since it is something that I am trying to improve on. I am the type of person that constantly need to be nudged when it comes go terminology. (yes, one of those blood bankers!!!)

 

Edited by dothandar

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On 3/20/2019 at 7:43 AM, Malcolm Needs said:

In the UK, the Lead Biomedical Scientist of the NHSBT Reference Laboratory decide, but the molecular work is largely done by the International Blood Group Reference Laboratory, and so they have the final say.

You all are so lucky to have direct access to such lab! 

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19 minutes ago, dothandar said:

You all are so lucky to have direct access to such lab! 

We are indeed, but with that comes responsibility to use the service properly.  Many a time I felt like I would like to send in a sample for molecular work, but my conscience wouldn't let me because it wasn't justified.

Once or twice, it genuinely was, and one of my proudest moments was when I was convinced that one of our samples came from a patient with a mutation within the KEL gene, and I persuaded Joyce Poole that a gene sequence should be performed, and it turned out I was right.  Joyce sent me a report that began "Well done Sherlock"!  Sadly, I made many more mistakes when I should not have insisted on molecular work!

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24 minutes ago, Malcolm Needs said:

We are indeed, but with that comes responsibility to use the service properly.  Many a time I felt like I would like to send in a sample for molecular work, but my conscience wouldn't let me because it wasn't justified.

Once or twice, it genuinely was, and one of my proudest moments was when I was convinced that one of our samples came from a patient with a mutation within the KEL gene, and I persuaded Joyce Poole that a gene sequence should be performed, and it turned out I was right.  Joyce sent me a report that began "Well done Sherlock"!  Sadly, I made many more mistakes when I should not have insisted on molecular work!

Interesting!! It will be a fun case study for us to learn from if you would be kind enough to post up this case on this site!

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