Anecdote: Serial Panels Reactivity

When I review nonspecific reactions on an antibody panel, I always check the outdate of the reagents and the age of the specimen.  Outdating reagents may show weak reactivity.  Old specimens may get contaminated and bacteria may alter the RBC surfaces (e.g. T-activation).

Here is an example of weakened reactions with an outdating antibody panel.  This panel was used one-week before its expiration:

Here is the same patient with the new panel with 5 weeks before its expiration:

Rh Discrepancy Workup

This is an old lecture I gave to medical technologists at National Guard Health Affairs in Jeddah. This was prepared in the pre-molecular blood bank era, but there is good common sense in it to deal with many interferences.

Inter-Depot Transfer, Blood Delivery, Type and Antigen Matching

This is an update of a previous post.

The final components from the component preparation center may be sent to various depots (freestanding location and/or hospital blood banks.  There should be complete traceability for every step (from donor reception, collection, testing, and processing) transport between locations, and finally the exact storage site, which might include which refrigerator/freezer/incubator and even shelf/position number for each component is stored.  The end of that document showed rules for type/antigen matching.

For disaster planning, rapid inventory enumeration by type is very important.  This can be very time-consuming manually.  With our Medinfo Hematos blood bank system, we could quickly get total inventory across the Qatar or by hospital in less than one minute.  We could also quickly find antigen-matched units across the system and reserve it at any one site for another if necessary.

Smart blood bank dispensing refrigerators, as offered by Haemonetics and Angelatoni, may also serve as depots and take the place of a hospital blood bank for some dispensing.  These solutions can also capture vital information about the storage conditions of the components and prevent release if the storage criteria are not met.  They can also interface with blood bank computer systems and use the main system’s logic for the dispensation rules.

Upon receipt at the hospitals from the blood processing center, the forward ABO and D typing must be confirmed.  We used D reagents which detected partial D so we would call such donor units as D-positive.  However, if a patient type reagent insensitive to partial D types is used, it is possible for a unit to be typed as D-negative whereas in the donor center it might be D-positive.  Sometimes, nothing types consistently as D-positive:  all you can say is that with a particular reagent and lot number, there is or isn’t reactivity.

The greatest complexity is for RBCs since potentially so many antigens exist.  Criteria for matching/ignoring certain antigens must be made.  Critically significant antibodies such as the Kell, Duffy, Kidd, and certain Rh (D and c) must be antigen matched.  A robust blood bank computer system can enforce these rules.

For other components, antigen/typing may be less important.  In fact, in most situations, any type of platelets can be given to anyone (except neonates).  Despite the potentially incompatible plasma, there is rarely significant hemolysis.  In fact, if pooling platelets without regard to blood types is done, a platelet transfusion is a common cause of a positive direct antiglobulin test DAT—something that is not clinically significant.  No one died of a positive DAT by itself for this reason.

Specific rules for compatible plasma types are important, but nowadays, low-anti-B-titer group A plasma may be used like universal AB plasma.  The challenge is to be able to perform the ABO titration (specifically anti-B) quickly—titration can be a slow process, even with automated equipment.  A similar situation for low-titer, universal group O whole blood requires both anti-A and anti-B titration (I will return to this topic in a future post).

Antiglobulin Reagents

Antiglobulin reagents are used to detect molecules bound to the RBC surface.  What they detect depends on their specificity.  Such detection can be performed in the routine immunohematology laboratory or elsewhere such as flow cytometry.  This discussion is for the blood bank laboratories, both routine and reference immunohematology.

This is how I classify and use the various reagents in my daily practice:

  • Routine use—DAT testing and compatibility testing
  • Antibody identification
  • Drug-related hemolysis and transfusion reaction workups
  • Special assays:  DAT-negative AIHA, prediction of clinical significance of reaction by IgG subclass determination

There are many types of antiglobulin reagents:

  • Polyspecific:  IgG and complement usually C3d but sometimes C3b specificity included
  • Whole Molecule IgG including mu heavy chains and kappa and lambda light chains
  • Monospecific gamma heavy chain, mu heavy chain, alpha heavy chain, C3c, C3d, C3b
  • IgG subclass:  IgG1 IgG3

Whole molecule IgG detects class-specific mu heavy chains AND light chains kappa and lambda.  Since kappa and lambda are found on all immunoglobulin classes, whole molecule reagents can detect IgM so there may be weak staining with cold antibodies that are not clinically significant.

C3d is the final breakdown product of C3b and does not cause hemolysis.  Its presence merely means that at some time—unspecified—complement was fixed.  C3c is an intermediate product in the breakdown pathway.  If detected, C3c positivity means ACTIVE complement fixation was occurring at the time of specimen collection.

General Use:

Routine DAT testing:

  • Polyspecific:  if positive, then use
  • Monospecific IgG and monospecific C3 reagents

Antibody workups:

Routine:  antibody screens and AHG crossmatch (if indicated)

  • Polyspecific
  • Gamma heavy-chain monospecific

Monospecific gamma heavy chain is preferred to minimize non-clinically significant, cold antibody interference.

Complicated—where detection of complement reactivity is especially important:

Polyspecific for drug-related hemolysis and transfusion reactions

Difficult antibody workups, e.g. to rule out anti-Jka and/or anti-Jkb

Specialty Reference Procedures:

  • DAT-negative AIHA:  mu heavy chain, alpha heavy chain for IgM and IgA mediated hemolysis (rare), C3c to detect active complement fixation
  • Predicting clinical significance:  IgG1 IgG3

Complement fixation may be important in various drug-related hemolysis and some transfusion reactions so I always use a polyspecific reagent in these situations.  Most antibodies can be detected by gamma heavy-chain specific reagents;  however, there are rare examples of anti-Jka and anti-Jkb which are only detected by complement.  Whenever I have a nonspecific reaction in an Jka-negative or Jkb-negative patient, I repeat the AHG panel using polyspecific reagents.  I do not use polyspecific routinely because of the nonspecific and non-clinically significant cold antibodies.

One way to assess for the clinical significance of an antibody is to determine its IgG subclass.  In general, IgG3 antibodies may fix complement and cause severe hemolysis.  Both IgG1 and IgG3 antibodies cross the placenta and may cause hemolytic disease of the fetus/newborn.

In summary, when reviewing immunohematologic reactions using AHG, I always remember to check which type of AHG reagent was used.  I always keep multiple types of AHG reagents in the laboratory for the reasons explained above.

Summary of Accomplishments at Hamad Medical Corporation 2011-2020

2011

Established automated component production using Atreus technology, plasma and platelet pathogen inactivation (Mirasol)—made HMC component production Good Manufacturing System GMP compliant

2011

Qatar is the first to adopt non-PCR-based NAT technology (Grifols/Novartis Tigress) and becomes world reference site for this

2011

Based on the above, Qatar can now completely process all whole blood into blood components (red cells, platelets, and plasma) in as little as 5 hours from collection!

2011-2020:

I established policies and procedures for the hospital blood banks/transfusion services, blood donor center, therapeutic apheresis, and laboratory information systems to bring HMC in compliance with the Council of Europe, international AABB, and other standards.  I customized our own standards for our local needs based on them.

2012-2013

Implemented custom build of the multilingual blood bank computer system (Medinfo) for both patient and donor services, including development of interfaces to all production equipment including Atreus and Mirasol (world’s first) and a direct link to Ministry of the Interior to obtain patient demographics in English and Arabic—Qatar became the world’s first site to combine fully-interfaced, automated component production with pathogen inactivation:  Qatar becomes world reference site for this.

2013-2014

Built, validated, and implemented laboratory build of hospital information system, Cerner Millennium

2015

Replaced and updated Atreus with Reveos automated component production to allow faster throughput and capacity with a full bidirectional interface (world’s first), introduced platelet

additive solution PAS with pathogen inactivation (Mirasol)—Medinfo interfaces updated to Reveos for all equipment:  this doubles the capacity to process whole blood into components using the same physical space

2015-2019

Updated dedicated blood bank software Medinfo Hematos IIG by several versions using Division Head, LIS, and internally trained Super Users—at great cost savings to HMC by not using outside consultants (e.g. Dell Consulting)

2019

Established column absorption technology using Terumo Optia therapeutic apheresis machine for treatment of ABO-incompatible renal transplants:  I validated using the Ortho Vision MAX to perform ABO antibody titers for this system and correlated it with the reference method at Karolinska Institutet in Stockholm (manual gel) to bring rapid throughput and labor savings—Qatar being the first-site in the world to do this.  We saved money by using the same apheresis machine to use this column absorption technology (no need for second machine to use the columns)

2020

Expedited setup (two weeks total) of COVID-19 convalescent plasma production, initially manual and then fully integrated into the Medinfo computer system as a customized module with separate quarantine collection, production, and transfusion service functions

Other:

I was awarded two HMC Star of Excellence Awards:

2013—Liver Transplantation Transfusion Support

2019—ABO-Incompatible Renal Transplantation Support