Category: Patient

Includes compatibility testing (AHG, electronic, immediate-spin), antigen typing, antibody screening and identification, direct antiglobulin testing, elution, transfusion reaction and drug reaction workups, component typing tests upon receipt in hospital blood bank, release and return of components

DAT-Negative Hemolytic Anemias

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This is a summary diagram for the causes of DAT-negative hemolytic anemia, both immune and non-immune. For immune cases, a negative DAT may indicate “not-detected” with the amount of immunoglobulin on the RBC being below the threshold of the test methodology being used. Also rare IgA associated cases will not be detected unless a specific alpha-heavy chain monospecific reagent is used.

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

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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.

Therapeutic Apheresis Policy

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This has been revised to recommend the use of a continuously recording portable vital signs device such as Umana’s UT1M (GPI, Italia) which includes PAO2 and heart rhythm measurements.

Principle:

All therapeutic apheresis procedures are potentially life-threatening and must only occur by an order from a transfusion medicine physician with experience/competence in such procedures.

Definitions:

  • Referring Physician is the clinical physician requesting a therapeutic apheresis procedure.
  • Transfusion Medicine Physician is a physician in the Transfusion Medicine Section with medical privileges for therapeutic apheresis procedures.  This includes the Head, Transfusion Medicine, consultants in Transfusion Medicine, and designated specialist physicians in Transfusion Medicine.  The final decision to accept/reject the patient is made by the transfusion medicine physician.
  • Covering Physician is the clinical physician designated by the referring physician to be physically present and covering the patient in case of any adverse reactions during a therapeutic apheresis procedure.
  • Apheresis Nurses are nurses in Transfusion Medicine who are designated by this section for performing therapeutic apheresis procedures.
  • Medical Privileges are determined by Transfusion Medicine in conjunction with the medical privileging by the Medical Director.

Policy:

  1. The referral physician will discuss the request for a therapeutic apheresis with the designated transfusion medicine physician.  The referral physician must certify that the patient can tolerate the procedure based on his medical condition.
  2. The transfusion medicine physician will review the patient’s clinical and laboratory data, with special note of the history of allergies, medications, previous transfusion reactions, and current vital signs.
  3. Vascular access will be initially assessed by the apheresis nurse.  Any questionable situations will be reviewed by the transfusion medicine physician.
  4. The following laboratory values (less than 24 hours old) must be available before the procedure may begin:
    1. CBC including platelet count
    2. PT and APTT
    3. Fibrinogen
    4. Serum calcium
    5. Serum protein and albumin
    6. LDH for TTP cases
  5. A valid type and screen must have been done within the previous three days of the procedure.
  6. Upon review of # 2 through 5, the transfusion medicine physician will determine if the procedure is indicated and will communicate this to the referral physician, who will sign written order in the patient chart.  Appropriate replacement fluids will also be mutually agreed upon in advance of the procedure and ordered by the transfusion medicine physician.  The order specification must include:
    1. Name of procedure and specification (e.g. therapeutic plasma exchange, isovolemic)
    2. Replacement fluid type and volume (e.g. 3 liters 5% albumin, 2 liters, FFP, cryoprecipitate, normal saline)
    3. Blood component orders if indicated (e.g. RBC exchange) and timing (before, during, and/or after the procedure)
    4. Calcium replacement (e.g. 2 grams calcium gluconate IV in 100 ml normal saline to run during the procedure)
    5. Any special laboratory testing post-procedure
  7. The apheresis nurse will follow the orders of the necessary prescribed replacement fluids (FFP, albumin, PPF) in the quantities necessary for the exchange.
  8. The referring physician will obtain the signed, informed consent from the patient.
  9. If vascular access is unsatisfactory, the referring physician will obtain the proper access (central line, AV shunt, etc.).
  10. The referring physician will arrange for a physician member of his team to be present at the actual therapeutic procedure.  This physician designate will be responsible to treat any complications arising from the procedure.
  11. Vital signs and weight will be obtained before starting the procedure.
  12. If the procedure is outside an intensive care unit and the patient is critically ill, consider the use of a portable attached monitoring patch (such as the Umana UT1M device).  The device will give alarm if any measurement is outside the defined ranges.
    1. If any blood components are administered, keep the patch attached to detect TRALI/TACO and other adverse transfusion reactions.
  13. When approved by the Blood Bank Director or designate with proper venous access and informed consent, the apheresis may start the procedure in the presence of the patient’s covering physician.  The procedure will be performed in a designated hospital area.
  14. The procedure must be documented on the appropriate therapeutic apheresis order and procedure worksheets.

References:

  1. Standards for Blood Banks and Transfusion Services Current Edition, AABB, Bethesda, MD, USA
  2. CAP Standard TRM.42245 regarding therapeutic apheresis procedures

Revised 3/1/21

International Perspective

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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.

Policy: Selection of Components for ABO-Incompatible Renal Transplants

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Principle:

Kidneys have strong expression of ABO type and must be matched the same way as RBC components.  In the case of ABO-incompatible renal transplants, we must not give significant amounts of plasma incompatible to the ABO type of the donor kidney.  Plasma must also be compatible with the patient’s ABO type for RBC transfusions.  The amount of residual plasma in PRBCs is limited since we use an additive solution SAGM.  Likewise, platelet components are suspended in platelet additive solution with only minimal residual plasma.  Cryoprecipitate has only minimal plasma and is given without regard to the patient’s ABO type.

All of the following rules can be built into the blood bank computer system Medinfo without hard coding.

Policy:

  1. RBC components:  Use ABO-compatible RBCs in SAGM.  DO NOT USE WHOLE BLOOD!!
  2. Platelet components in platelet additive solution PAS (normally available component):  Any ABO type may be given
  3. Platelet components in plasma:  Only group AB platelets may be used.
  4. Plasma (any type FFP, FP24, solvent-detergent treated, or thawed):  Only group AB plasma may be used
  5. Cryoprecipitate:  Any ABO type including mixed types may be used, mixed types are preferable to neutralize the minimal ABO-incompatible plasma.

References:

  1. Standards for Blood Banks and Transfusion Services, AABB, Current Edition, Bethesda, MD USA
  2. Technical Manual, AABB, Current Edition, Bethesda, MD, USA

My Experience: Blood Bank Considerations for Setting Up ABO-Incompatible Renal Transplantation

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Setting up ABO-incompatible renal transplants is a major undertaking and requires close coordination between Transfusion Medicine and the clinical team.  This post addresses my experience in setting up this program in 2019 at HMC in Qatar.

Like any process involving titration, it is best to automate it to minimize inter-technologist variability.  Unfortunately, doing both IgG and IgM titers takes up to 1 hour per machine and totally monopolizes the machine during that interval.  I did not have sufficient staff to even consider doing the titrations manually.  Performing automated titers disrupted my workflow so I encouraged the clinicians to send the specimens for off-peak processing.

Titration:

  1. Obtain the full clinical protocol and especially note the thresholds for transplantation.
  2. Determine the methodologies used at the reference site.  Can you do this at your local site or do you have to use an alternative method?
  3. Do you have equipment to automatically titer?  Doing both IgG and IgM may monopolize an immunohematology analyzer for one hour?  How will this affect your other testing?
  4. Regardless if it is the same method, you must still correlate your titers with the protocol site, both IgG and IgM.
  5. If you are using multiple analyzers for titration, you must do a comparison study between them.  How much does the titer vary?

Columns:

  1. Determine column inventory and order the A, B, and AB columns.  You must order enough to finish the course of treatment.  It may take weeks to get additional columns, depending on your supply chain.  Each column costs thousands of euros.
  2. Where are you going to store the columns?  Ours needed 2-8C storage.  Can you keep them away from quarantined products and patient specimens?
  3. Are your columns single-use? 
  4. If multi-use, who is going to restore them after use?  How do you ensure that it is dedicated for the right patient?

Apheresis Equipment:

  1. How are you going to attach the column to the apheresis equipment?
  2. Will you use your therapeutic apheresis equipment like Terumo Optia directly or will you use a second machine (e.g. Medicap)?
  3. Do you have all the clamps, tubing, and holder for the column?

Staffing:

  1. Do you have sufficient apheresis nurses to perform the procedures?  You may be running the apheresis for up to 8 hours.  How does this impact your other procedures or donor center operations?  Our pool of apheresis nurses was very limited.  They also covered routine blood donation.  How will doing this process impact your regular donation and other apheresis operations—donor and therapeutic?
  2. Do you have sufficient supplies of ACD-A anticoagulant and calcium gluconate?

Specimen Collection:

  1. Perform titrations expeditiously:  Can you finish titration testing before the next scheduled procedure?  In our institution, we collected specimens at 0400 and had them directly brought to the blood bank for testing.  Results were ready at 0600 so the clinicians could decide early if another procedure was needed.

Table of Permissible ABO Types:

  1. Define acceptable blood products by blood type—take into consideration pathogen inactivation and platelet additive solution if used.  At our institution, all RBCs were in additive solution and all platelets were pathogen-inactivated in platelet additive solution PAS so residual ABO antibodies were minimal in the final components.  Since the platelets contain only minimal plasma, we did not concern ourselves with matching their ABO type with the donor kidney.  Otherwise, platelet types with plasma compatible to the donor kidney must be selected.

Software:

  1. Prepare a truth table for acceptable ABO component types based on #16 above.
  2. Include the titer cutoff for IgG and IgM antibodies in the organ transplant module.

Selection of blood component for ABO-incompatible renal transplantation is discussed in a separate post that will follow.

25/12/20

COVID-19 Convalescent Plasma CCP Series Introduction

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I will be posting a detailed series about the manual and software-enhanced COVID-19 processes that I set up in Qatar at HMC Doha in March-April 2020.

In this series I will provide you with screen shots of my Medinfo Hematos IIG software design for each step in the process:  collection, processing, testing, inter-depot transfer, and hospital transfusion service/blood bank release.

This GMP-compliant software-enhanced system is based on the manual system I set up in early March 2020 at HMC.

I want to thank Medinfo Hematos IIG for their rapid response to building this parallel system based on my standard processes in so short a time (two weeks) and my special thanks to the software engineering team at Vital Health Technologies, the agent for Medinfo in Qatar.

To start the series, I am providing the basic workflow for the system.  As is normal in Medinfo software design, a full mapping of the processes are made.  This workflow shows the new CCP ISBT codes and the quarantine collection and processing steps.  The donor testing (marker and immunohematology) processes are similar to those for regular donor units.

This is basically the same process both manually and in the software.  I always say:

A good software process is based on a good manual process!!

Please note the following workflow for our initial discussion.

Leukodepletion Apheresis Form

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This form is the result of a collaborative effort between my therapeutic apheresis team and me. I want to thank Dr. Saloua Al Hmissi, Consultant, Transfusion Medicine, and Ms. Mini Paul, Head Apheresis Nurse for all their efforts.

This form can be readily converted into a computer data entry form–depending on your software’s capabilities.

Use of Universal Low-Titer Group A Plasma

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Principle:

Since group AB plasma is in short supply, use of group A plasma with low anti-B titers may be substituted based on inventory levels.

Policy:

  1. If the AB inventory is low, we will test group A donors at the time of collection for anti-B titers.
    1. The numbers to be tested will depend on the level of the shortage and the availability of equipment to perform titration.
  2. Use the automated analyzer to perform saline anti-B.
    1. If the saline titer is less than or equal to 1:64, the plasma may be used for recipients of any ABO blood group and will be labelled as group AU—A Universal.
  3. Process the unit routinely and perform pathogen-inactivation.
  4. Medinfo Hematos IIG will only label for universal use if the titer is below the cutoff.
    1. The ISBT label must explicitly show group AU plasma and the actual anti-B titer.
  5. Allocation rules for low-titer group A plasma will be identical to group AB except:
    1. For neonates, preferentially use group AB.
    2. For children < 20 kg, use ABO-compatible plasma (non-group AB) before selecting group AB or if not available, low-titer A in that order.
  6. Donors must have a new anti-B titer performed each donor encounter.

References:

  1. Technical Manual, Current Edition, Bethesda, MD, USA
  2. Standards for Blood Banks and Transfusion Services Current Edition, AABB, Bethesda, MD, USA