Processes and Software Building 56: RBC Distribution Rules

In Medinfo HIIG, one sets parameters to determine which antigens must be matched to allow a RBC product to be released.  These criteria may include:

Number of and timing of ABO/D typings

Permissible ABO/D substitutions

Emergency release

Required antigen matches

Optional antigen matches

Exact wording of conditional and blocked combinations

For ABO/D typing, a minimum of two typings must be on record for routine release and the last typing done within 72 hours.  If not, emergency release must be selected.  ABO-incompatible selections must be blocked.  For D-negative patients, only D-typed units may be selected.  D-incompatible transfusions will trigger a message to use D-compatible for females <50 years.

Required antigen typings include using antigen-negative for patients having antibodies against the specified antigen, e.g. D-negative RBCs for patients with active anti-D, c-negative for patients with anti-c, K-negative for anti-K, etc.

Certain antibodies will trigger a message to flag the use of unmatched units but not block the release.

The attached document shows sample settings for RBC release.  Note that these rules are user-definable.

31/10/20

CMV Prophylaxis Policy

I developed this policy for HMC Doha where most of the local population are CMV-seropositive. Note that I used the CE definition of <1E6 instead of the American <5E6.

Principle:

Since most of the local population (>90%) are CMV-seropositive, it is impractical to rely on CMV-negative donors as our basis for CMV prophylaxis.  Instead, we perform universal leukodepletion and pathogen-inactivation to greatly reduce this risk:

  1. CMV transmission risk can be lowered to a level comparable to using CMV-seronegative components by universal leukodepletion to levels <1E6.
  2. Pathogen inactivation greatly reduces (at least 2 log10) the number of organisms with nucleic acid (DNA or RNA) and is used for all platelet (pools and apheresis) and plasma components.
  3. Platelet additive solution reduces the amount of original plasma to about 35 ml and further reduces donor exposure to foreign material.

Policy:

  1. All blood components (platelets, plasma, RBCs) are universally leukodepleted to residual levels below 1E6.
  2. All platelet and plasma components are pathogen-inactivated using the Mirasol system (riboflavin added and then exposed to ultraviolet light).
  3. All platelet components (pooled buffy coat and apheresis) are prepared in platelet additive solution PAS.

References:

  1. Technical Manual, AABB, Current Edition, Bethesda, Maryland, USA
  2. Standards for Blood Banks and Transfusion Services, Current Edition, AABB, Bethesda, Maryland, USA
  3. Guidelines to the Preparation, Use, and Quality Assurance of Blood Components, European Committee (Partial Agreement) on Blood Transfusion (CD-P-TS), Current Edition

Processes and Software Building 46: Reconstituted Whole Blood

Exchange transfusions using reconstituted whole blood were much more common in the past.  Much of the time IVIG now takes care of hemolytic disease of the fetus/newborn HDFN.

In Medinfo, we took a fresh (<= 14 day old) packed RBC in SAGM, group O, Rh-compatible and mixed it with a unit of group AB plasma—the desired hematocrit could be achieved by adjusting the amount thawed plasma that we added.  The product could then be aliquoted and irradiated.  Note that I medically chose to use either FP24 or FFP.

Here is the Medinfo process:

19/9/20

Laboratory Software from Hell 1

In my career, I have dealt with many different laboratory software vendors.  Regretfully, not all encounters have been straight-forward. 

Things that bother me:

  • Current state:  whoever prepared it for the client, didn’t care or understand the local processes and came up with a generic:  order it, collect it, receive it, do it, report it for each and every test
  • No training for super users:  more like lambs being led to the slaughter
  • No discussion of options:  pushing client to take the default settings
  • Corrections to build:  only giving one shot to do it right, further corrections cost $$
  • Scenarios:  vendor shows specially crafted scenarios that “work” but when you ask the vendor to do a random, non-scripted scenario, it crashes
  • Scalability:  limited scalability on client’s chosen platform
  • Reference site does not match the test volume or activities of the client, uses different platform, and thus cannot be compared

I will give further examples in upcoming posts.

18/9/20

Donor Deferrals for Body Fluid Exposure

Principle:

New rules have been approved by US FDA CBER for body fluid exposure, tattooing, body fluid exposure, and body-piercing.  By similar logic we will extend this also to HIJAMA.  We will not make any changes to our sexual history/practices or history of sexually transmitted disease treatment.

Policy:

  1. Effective immediately, we will accept donors AFTER THREE MONTHS from the following activities:
    1. HIJAMA (ritual blood-letting)
    2. Tattooing
    3. Body piercing (e.g. piercing for ear-rings)
    4. Contact with blood of another individual through percutaneous inoculation such as a needle stick or through contact with a donor’s open wound or mucous membranes
  2. A TWELVE-MONTH DEFERRAL still applies after receiving a blood component or blood derivative except clotting factors.
  3. Transfusion of clotting factors remains a permanent/indefinite deferral.

Reference:

Revised Recommendations for Reducing the Risk of Human Immunodeficiency Virus Transmission by Blood and Blood Products, Guidance for Industry,  U.S. Department of Health and Human Services, Food and Drug Administration, Center for Biologics Evaluation and Research, April 2020

Processes and Software Building 45: Modifying RBC Components

Components may be modified either in the Blood Donor Center or in the hospital blood bank.  In either case, they use the PRODUCTION section of Medinfo to perform these operations.

These operations may include:

  • Irradiation
  • Tight-packing (removal of the supernatant, especially for intrauterine or neonatal transfusions)
  • Washing
  • Aliquoting (division of the primary RBC bag and possibly further division of one of the secondary bags)
  • Final labelling of the modified component

The weight of the component is converted to the volume by the software.

The end-user can specify which modified components were available.  As with any ISBT-labelled products, any changes will trigger a new ISBT E code and label.

16/9/20

Selection of Components for ABO-Incompatible Renal Transplants

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.

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

Policy: ABO-Incompatible Plasma for Infants

Principle:

HMC Blood Donor Center used platelets (buffy coat pools) and/or apheresis-derived suspended in PAS (platelet additive solution).  In each platelet pool or apheresis platelet, less than 35 ml (average < 20%) of the original plasma. This was much less than would remain if volume-reduced platelets had been prepared by centrifugation. Furthermore, the platelets would NOT be traumatized by the centrifugation.

Policy:

  1. For neonates (< 4 months old) and infants (<20 kg), we will give preference to use plasma-compatible platelet and plasma type.
  2. In any case, PAS-suspended platelets will be used with little residual plasma (far less than if we had centrifuged them).
  3. In the rare event that plasma-compatible platelet types are not available, the transfusion medicine physician must approve the release.

References:

  1. Standards for Blood Banks and Transfusion Services, Current Edition, AABB, Bethesda, MD, USA
  2. Guide to the Preparation, Use, and Quality Assurance of Blood Components, European Committee (Partial Agreement) on Blood Transfusion, Council of Europe, Strasbourg, France

Processes and Software Building 44: Pooling Components

Medinfo Hematos IIG has a pooling operation that can be used for pooling platelets, plasma, cryoprecipitate, etc.  It is a one-step operation.  In the set-up, one specifies the maximum number of components to pool together for each component type.  In general, they are of the same ABO type;  however, at HMC Doha I did allow mixed ABO platelet pools to avoid wastage of platelets that would otherwise be discarded—this may not be allowed in all jurisdictions.

The following examples show pooling of FFP, FP24, cryoprecipitate, and cryo-poor plasma:

13/9/20