Washed RBCs

Note:  This is an updated version of a previous post.

Principle:

Washing RBCs removes plasma and reduces the leukocyte count only by 1 log.  For leukodepletion, we must rely on filtration to reduce the WBCs to less than 1 x 106 per unit according to CE rules.  Red cells or platelets in additive solution contain only minimal plasma (about 35 ml).  There are few definite indications for washing RBCs and it should be rarely necessary.

Policy:

Washing RBCs should only be done in the following circumstances:

  1. Deglycerolization of frozen RBCs.
  2. Severe allergic or anaphylactic reactions to plasma proteins
  3. IgA deficiency with anti-IgA
  4. Paroxysmal nocturnal hemoglobinuria PNH—relative indication (often these patients receive RBCs before the diagnosis of PNH is confirmed)
  5. Transfusing a previously irradiated RBC unit for pediatric use if more than 24 hours has passed since it was irradiated.
  6. Any other time when so designated by a transfusion medicine consultant.

Note:

  1. If anyone requests washed RBCs and it does not fit into one of the above categories, contact the transfusion medicine consultant.
  2. Washed RBCs are NO substitute for leukodepleting RBCs by filtration NOR can they be used in place of irradiation for prophylaxis against transfusion-associated-graft-versus-host disease TAGVHD.  Using the Reveos automated component processing system, all components are leukodepleted—RBCs are released in SAGM.

Reference:

Standards for Blood Banks and Transfusion Services, Current Edition, AABB, Bethesda, MD, USA

COVID-19 Convalescent Plasma CCP Donor Questionnaire and Collection

This is a part of a series of posts on the actual Medinfo design of the CCP donation and release processes.  The site and donor registrations were covered in a recent previous post.

Donor Questionnaire and Physical Examination:

After registration, there is the online CCP donor questionnaire and vital signs entry.

Note that the CCP donor will automatically be excluded from other types of donation.  All other types will appear as contraindications in RED below.

Donor Apheresis Collection:

The actual donation process is the same as for plasmapheresis donors:

Further Thoughts on Inter-Depot Transfer, Blood Delivery, Type and Antigen Matching

In my recent post, I provided sample flows and parameter mapping for delivery of blood components.  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.  In Medinfo, they can be added as a hospital blood bank site.

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-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).  With Medinfo, I can define rules (e.g. IgM titer < 1:64) to accept these units as a universal type for all ABO groups.

Special rules can be built into the software so that production, transfer, storage, and release of COVID convalescent plasma CCP are only performed at special quarantine sites by designated personnel.  This means there can be dedicated transport pathways built into the inter-depot transfer process to keep this inventory separate at all times.

Logistics and Processes for a COVID-19 Convalescent Plasma Program

I prepared the following plan for a CCP program for HMC Qatar in March, 2020.  The workflow is divided into four (4) modules:

  1. Registration/Interview/Physical Examination/Apheresis Collection
  2. Donor Marker Testing and Immunohematology Testing
  3. Production/Aliquoting/Pathogen-Inactivation/Storage
  4. Product Thawing/Product Release

Module 1:

  1. Collection/registration/screening must be in a separate area from regular blood and apheresis donations.
  2. Donors must provide consent.
  3. ISBT specimen labels must be used on each tube collected.
  4. We need a minimum of two apheresis nurses, one for the registration/screening/post-donation observation and one for the actual apheresis procedure.
  5. If there will be multiple serial donors, then we need a waiting area (each donor at least 2 meters apart).
  6. Donor screening must be in sound-proof area so that other waiting donors cannot hear the interview/questionnaire process.
  7. Amount that can be collected depends on body weight:  500 ml for <80 kg and 600 ml for >= 80 kg, collection may occur twice per week
  8. Collection time includes 15 minutes for registration/interview/physical examination, 60-75 minutes and 15 minutes for cleanup/disinfection before the next case, approximately 2 hours per donation.
  9. A post-donation observation area (minimum 15 minutes after collection) with apheresis nurse nearby in case of reactions is needed if there will be multiple donors.
  10. Specimens will

Module 2:

  1. Donor testing and donor immunohematology will be done with other donor specimens in our regular location

Module 3:

  1. Apheresis collection must be processed and stored separately from regular blood/apheresis donations.
  2. Processing will occur only after the results are shown to meet all criteria.
  3. Pre-collection testing (test-only donation) would permit processing without waiting for results.
  4. Storage at minus 80C may be for a minimum of six (6) years but this may be extended if needed.
  5. All acceptable components will have a final ISBT label—no products without the ISBT label will be transfused.  The ISBT label indicates that the unit meets all donor criteria for convalescent plasma.

Module 4:

  1. Product modification (thawing) and release (sign out from blood bank) must be in a separate area(s) from the regular hospital blood bank.
  2. Release of convalescent plasma follows the same process as regular component release
  3. Transfusion of convalescent plasma at the patient’s bedside follows same process as regular component transfusion
  4. Nursing and other staff performing the transfusion must pass competency assessment.
  5. Plasma will be transfused as ABO-identical or compatible unless low ABO-titer group A is used.
  6. Plasma must be free of clinically significant antibodies

Workflow Considerations:

  1. Donors must be restricted to the waiting, collection, or post-donation observation areas.
  2. Donors must NOT pass through production, testing, or component release areas (just as they are currently restricted in the Blood Donor Center and HMC hospital blood banks/transfusion services).

Logistics:

  1. Throughput is a maximum of 4 donors (2000 to 2400 ml plasma) per eight-hour shift with one apheresis nurse and one donor apheresis (Trima) machine.
  2. The processes are scalable with additional staff and machines (e.g. with 3 machines and nurses, then 12 donors and 6000 to 7200 ml of plasma collected).
  3. Thawing of 1-2 units of plasma takes up to one hour.  Contact the quarantine blood bank at least one hour before the desired pick-up time.
  4. The four modules above can be in separate areas not adjacent to one another.  Modules 1, 3, and 4 must be quarantine areas where access is limited.  Module 2 can be performed with regular donor specimens using standard precautions.
  5. We can provide training for transfusion of blood components and competency assessment to any location transfusing this product.

Information Technology:

  1. All modules will be connected to the Medinfo Hematos IIG dedicated blood bank computer system.
  2. All records of collection/production/testing/storage/modification/release will be stored therein.
  3. All ordering of convalescent plasma components will be through Medinfo.
  4. External test results (e.g. future antibody titering) can be added to the component information.
  5. Links to the Hospital Information System (Cerner) may be considered after the Medinfo processes are fully functional.

International Perspective

When I first moved overseas from the United States, I brought the perspective of my American training and experience.  I saw everything in my new blood bank through those eyes.

Yet, most of my staff were not American or even North American.  Few were even native in English, and most of those  were not American.  They had different qualifications, many of which would not have been accepted by the American schemes.  Still, they functioned well.

I also worked with the US military technologist staff during Gulf War One.  Some did not even have a Bachelor’s degree;  yet, they performed the work well.

I used many technologies that were not yet (or never) US FDA approved such as gel or glass bead typings and pooled buffy coat platelet production.  There were rare reagents I could buy off the shelf (e.g. anti-Tja/PP1Pk).

Later, I adopted pathogen-reduction technology (Mirasol), automated component production (Atreus then Reveos), and platelet additive solution.  I achieve a level of good manufacturing practice that would have been difficult to achieve by the FDA-approved methods.

My perspective had changed.  In the Middle East, I studied many frameworks and came to the conclusion that the best approach was to customize them to our local needs.  My particular experience was to start with one framework, i.e. Council of Europe CE, and then localize it.

To do this, I could not use an American turnkey blood bank software for either the donor or patient operations.  I needed a flexible system that could be customized to my needs.  Again, I chose a CE-marked system, Medinfo Hematos IIG that had already been adapted to many frameworks.

It is much easier to work solely within one system such as FDA.  However, if I had done that, I would have lost so much flexibility and not had a system optimized for local conditions.  I would not have used Mirasol, Reveos, Diamed, and many other reagents.

One big disappointment at such international meetings is the perspective by one country’s regulatory agency that they feel its regulations and framework will work well overseas.  I would wager that those people were not well acquainted with international conditions.

Another frustration was attending another international meeting in which the presenters apologized for the source of information since it came from a foreign country (France) and not their own (United States).

No country has a monopoly on what is best for everyone.  To share our experiences and compare is so valuable.  No one assume his way is the best.  In my career, I have had the richest experiences studying other perspectives and my organizations have benefited greatly from the exchange.  We can all learn from each other.  We are citizens of the world.

Reposted: Granulocyte Concentrates Prepared from Reveos Buffy Coats

The Reveos buffy coat is not approved for clinical use.  In my laboratory, I have offered this discard product to the stem cell laboratory and researchers as a quality control QC and a substrate to extract CD34+ cells for expansion and modification.

In this article (abstract attached) from Transfusion and Apheresis Science 59 (2020) 102682, the authors study pools of ABO-identical Reveos buffy coats for their granulocyte functionality and as a possible emergency replacement for granulocyte concentrates when the latter are not available.

I want to thank Terumo BCT (Brussels, Belgium) for referring me to this article and to the authors for a very interesting paper.

1/1/21