Tag: Donor Immunohematology

Donor ABO/D typing, antibody screening, antibody identification, ABO antibody titration

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

Framework for Establishing the Use of Universal Low-Titer Group A Plasma

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This post outlines a framework for establishing the use of low-titer group A plasma as a universal donor.  Manual titering large number of donor specimens in my organization is not practical.  Using an automated system will also increase the precision of the results.

Process:

  1. Select a cut-off anti-B titer.  This should be determined by the blood bank medical director.
    1. I selected saline 1:64 based on recent THOR (Thrombosis Hemostasis Oxygenation Research) meetings
  2. Perform a survey of the anti-B titers in your blood donor population.
    1. At my sites, about 50% had titers less than or equal to 1:64.
    2. Determine how stable the titer is:
      1. For serial donor plasmapheresis, how long could you accept the donor as low-titer?
      2. Does the titer change between whole blood donations?
  3. Determine the target inventory level for universal plasma (group AB and low-titer A) based on current/past usage.
  4. Assess availability of automated immunohematology analyzers for titration.
    1. Titration may take up to 30 minutes per sample, during which time the machine cannot be used for any other purpose.
  5. Add a new blood type AU (for group A universal) for plasma in your blood typing algorithm.
    1. AU should be used interchangeably with group AB.
  6. Software:
    1. Set up new truth table in your blood bank computer system.
    2. Validate the modification in your blood bank donor and patient modules.
    3. Update ISBT code for this new product, verify your transfusion service module can read this.

Special notes:

  1. At my last location, we had only 3 analyzers capable of doing the titration.  Thus, we could only do 6 titrations per hour at the expense of stopping all other testing.  You will have to coordinate the titration with your other immunohematology testing.  Also, verify if all these equipment interface to your production software.  In my system, any test (including titration) could be performed at any location and its results be used for production purposes.
  2. Donor ABO antibody titers may fluctuate.  I would not use previous results to qualify a donor to be AU.  I would repeat the anti-B titer each donor encounter.  If I collect donor plasmapheresis, I would determine for how long the titer can be used (see 2.2.1 above).

References:

  1. Technical Manual, Current Edition, Bethesda, MD, USA
  2. Standards for Blood Banks and Transfusion Services Current Edition, AABB, Bethesda, MD, USA
  3. Medinfo Hematos IIG Donor Production Module

Data Entry Verification: Updated Version

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This is an update from the previous version posted to include low-titer group A FFP/FP24 and low ABO-titer group O whole blood.

Principle:

This policy outlines steps taken to minimize the risk of data entry errors and is based on a dualistic approach:  review of results by a senior technologist and/or supervisor and various computer safeguards built into the Medinfo Hematos IIG blood bank computer HIIG system.  This policy also discusses the verification (here called authorization) and purge processes of HIIG.

Policy:

  1. Review by senior technical, supervisory, or transfusion medical staff:
    1. Designated test procedures require review by a second technologist before authorization.
    2. Complex immunohematology testing and specimens showing aberrant results (e.g. ABO/D discrepancies) are reviewed by the supervisors or designates and ultimately a transfusion medicine physician before authorization.
  2. Computer system HIIG rules:
    1. Privileges:
      1. System restricts which staff can perform specific tests
    2. Patient/donor identity:
      1. System asks end-users to verify patient/donor identity before starting any access to the patient/donor record.
      2. System performs historical database checking and flags any inconsistencies (e.g. historical ABO/D typing differences, etc.)
    3. Testing:
      1. Only selected staff have privileges to authorize or purge.
      2. ABO/D testing algorithms require entry of reactions, not interpretation of results and are compared to a truth table.
        1. Aberrant results require special review before ABO/D typing results can be authorized/purged.
        2. D-controls must be negative to allow D typing results to be authorized for liquid D-typing reagents.
      3. DAT results require appropriate controls to meet truth-table criteria.
      4. Eluates require last wash to be negative before authorization
    4. Blood components:
      1. Selection of RBC or plasma units requires two independent sample determinations within 72 hours of each other.
      2. ABO-incompatible RBC or FFP/FP24 transfusions are not allowed.
      3. Titer-based ABO blood group selection:
        1. Low titer group A FFP may be used as universal plasma like group AB.
        2. Group O whole blood with low anti-A and anti-B titers may be used for all ABO types.
        3. Acceptable titer threshold is specifically defined as parameters in Medinfo.
      4. Donors with any detectable clinically significant antibodies are permanently deferred.
      5. Depending on the patient’s antibody history, release of RBC units may require antigen-matched units.  Examples:
        1. Mandatory matching (only antigen negative matched units allowed—no antigen positive or antigen-untyped units):  Antibodies against H, D, c, K, k, Kpa, Kpb, Jsa, Jsb, Jka, Jkb antigens, anti-PP1Pk
        2. Priority matching (incompatible or untested can be approved by a transfusion medicine physician):  C,E, e, Fya, Fyb, M, S, s
        3. Antigen matching not required:  Lea, Leb, N
      6. Least-incompatible crossmatch require special authorization to release
      7. Protocols to force irradiation or other modified components can be setup in HIIG.
    5. Donors:
      1. Donor tests have same criteria as the same test used in patient testing for controls, etc.
      2. Donor demographics are read directly from the Ministry of Interior database—no manual entry (bar code only used).

References:

  1. Workflows for Hematos IIG (1001 through 1005), 2013-2020
  2. Standards for Blood Banks and Transfusion Services, Current Edition, AABB, Bethesda, MD, 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

Opinion: Understanding Each Step of the Process

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During an AABB inspection many years ago, I observed the Lead Assessor interacting with a medical technologist at the bench.  As expected, the Assessor asked in detail about the test and where the documentation and any teaching aids were located.  Most importantly, the tech was asked to explain the procedure step-by-step and if they knew WHY each step was done and how the various outcomes affected the test.

In my opinion, the WHY is the most important issue.  In our testing and processing, we are not baking a cake.  We do not need a mindless automaton to perform the steps without knowing what they are doing.  To get it right, the technologist must understand why he/she does each and everything—and what are the consequences for not following the procedure precisely.  If the staff member knows this, he/she has respect for the process and is more likely to adhere to the proper method.

In my interactions with my staff, I want to engage them in the importance of their testing to the patient’s care.  If they know that the result may affect the care, they may become more respectful of their work since they are part of the patient care team.

I want them to understand what each of the various results will mean to the patient, i.e. how he will be handled.  I give them updates about the patient’s condition.  A caring technologist is more likely to follow the steps properly.  They understand that a deviation from the process may adversely affect the patient.

To this day, I often go to the technologists and quiz them about what they are doing, e.g. why do they add a particular reagent, why the incubation time is 15 minutes versus 60 minutes.  I encourage them to check and recheck what they are doing if they have any doubts.  Working the bench is not a quiz or examination.  If they are uncertain, I want them to seek out the information, ask questions.  In fact, I tell them there is no shame in saying, “I don’t know”—but be certain to add, “I will find out what to do.”

Blood bank can be fatal to those who guess.  Each of us must know our individual limitations and seek the necessary knowledge.  In fact, many of my assessments are open-book.  They can use any resource in the blood bank or references on-line.  This is real life:  I discourage them from relying on memory if they are understand.  Our end point is the correct action.

13/12/20

Enzyme Panel Details

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Principle:

Performing antibody panels using both enzyme (ficin, bromelin, and/or papain)-treated  and routine panel cells may be necessary to detect most clinically significant antibodies

Policy:

  1. Regular (LISS) panels are to be performed using AHG reagents whereas enzyme panels done by the gel technology must use the saline (NaCl)-enzyme card.
  2. Perform BOTH enzyme and routine panels in the following situations
    1. All patients with sickle cell anemia and thalassemia
    2. Antibody pattern of panreactivity with a negative autocontrol (see attached examples)
    3. Antibody workup that does not show a specific pattern with the regular panel alone
    4. Any case with a previous history of antibodies with a current negative antibody screen
    5. Any other case that you are directed to do so by the transfusion medicine consultant, supervisor, or senior technologist.
  3. Remember the reactivities of the following antibody specificities with enzyme-treated cells:
    1. Reactions may not be the same with papain vs ficin-treated cells!
    2. Enzyme-labile with both papain- and ficin-treated cells:  Fya, Fyb, M, N, Ge2, Yta, Rg, Ch, Pr, Tn, Mg, Mia, Cla, Jea, Nya, JMH, Inb
    3. Variable, enzyme-labile or weakened, some unchanged with both papain and ficin-treated cells:  S, s, U
    4. Variable reactions with papain (labile, weakened, unchanged, or increased) but usually increased or unchanged with ficin-treated cells:  Kell system (K, k, Kpa, Kpb)
    5. Reactions are increased or unchanged with both papain and ficin-treated cells:  Rh (D, C, c, E, e), Jka, Jkb, Lea, Leb, Lua, Lub, P1, H, most cold antibodies, autoantibodies, Tja (PP1Pk)

Example 1:

Antibody to High-Incidence/Prevalence or Public Antigen:

Reactions destroyed by enzyme (typical of anti-Ge2):

Example 2:

Antibody to high-incidence antigen, reactions unchanged or enhanced by enzyme—VERY DANGEROUS PATTERN:  Examples:  Anti-H, Anti-Tja (PP1Pk), anti-k (cellano), anti-U

Processes and Software Building 56: Multi-Site Patient and Donor Considerations

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As our hospital network expanded, there were many patients who moved between locations.  They might first start in an emergency room and then be transferred to a specialty hospital.  These locations might be served from different hospital blood banks/transfusion services.  What happens if work is progress from one site when the new site receives the patient.  Must the previous workup be repeated or could it be used for transfusion at the next site?

For example, the ABO typing could be performed at one site and the antibody screen at a second site, and the antibody identification at still another site.  Could the results be used across the entire system?

I had multiple hospital blood banks and blood donor centers.  The general and specialty laboratories had multiple sites.  The hospital information system was set up so that the various tests could only be performed at specific designated sites.  This posed problems as patients were moved around or if some site(s) became inoperative since the specimens then had to transported at great distances for testing.  Only a few basic STAT tests were available at all sites.

It was my decision to allow all test categories at all sites, e.g. a DAT request from any site, any methodology, could be used to satisfy the order.  Similarly, all donor processes were available at all donor centers (the processes could be completed at one or more sites).  Different hospital blood banks had different equipment but all the test categories were the same across site—the methodologies might differ.  We had at least four different DATs across our system.

The interface between the blood bank and hospital system worked as follows:  In the hospital information system HIS, test orders pointed to a category of testing and any methodology for that category at any site could be used in the blood bank system for testing and reporting back to the HIS.  Any test in a category from any site could be used to satisfy the test request.  Blood bank staff would choose the particular test methodology to use.  It was NOT specified by the HIS!

In summary, for blood banks and donor centers within our system, the work could be flexibly moved between sites.  There was no need to repeat testing when a patient transferred to a new site.  The only type the work was repeated if testing was done at an institution outside our system.

Training Future Transfusion Medicine Physicians: Need for Technical-Medical Expertise

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In a previous post, I discussed transfusion training for hematology fellows and general pathology residents.  I have no expectations that most of them have any interest in the field so I suggested concentrating on the interpretation of the direct antiglobulin test DAT and turn-around-times for services.

In contrast, the transfusion medicine physician in-training needs to understand in detail all processes, donor and patient—especially test interpretation so that he/she can make medical decisions and variances.

During my training, I was fortunate to be in a residency training program that also had an American Specialist-in-Blood Bank SBB training program.  To a large extent, I attended the SBB program and even worked on the “wet” specimens.

I had no delusions that I would ever function as technologist or SBB in the blood bank.  However, that extended blood bank training has made me the physician I am.  I can correlate advanced, even reference, procedures to my medical knowledge and thus provide a unique offering.  In contrast, even the SBB is not a physician and cannot make the medical correlations.  Recently, I was flattered at an AABB meeting when the speaker thought that I was an SBB.

In certain regions where reference immunohematology laboratories and SBBs or equivalent are rare, the transfusion medicine should have sufficient technical background to help fill this gap.  In my practice, I review all antibody and DAT workups and make interpretative comments for the physicians and nursing staff.  These comments are entered into the blood bank computer system.

I personally tutor the trainees and make certain that they understand potentially dangerous patterns such as antibodies to high-incidence antigens, significance of the autocontrol in panreactivity, and assessing for fatal acute transfusion reactions—both hemolytic and non-hemolytic.

It also helps when I can discuss with my technical staff my interpretations and choices for clinical management.  They get a better idea how important their work is for patient care and understand how any errors may adversely affect the patient.

In regions where there are good immunohematology reference laboratories, some of this may be less necessary.  I lament that transfusion medicine physicians may not maintain these skills and must rely on others to their detriment.  Even if one is comfortable with this, the physician is still ultimately responsible for making the clinical decision.

ABO Subgroup Testing for Organ Donors

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Principle:

Organ donors with a history of RBC transfusion within the past three months must have ABO subgroup (weak A as detected by A2 cells and anti-A1 lectin) if the transfusion included group A RBCs.

Policy:

  1. Organ donors who are typed as A should be tested to distinguish group A1 from weak subgroups of A.
  2. Use anti-A1 lectin and A2 cells as indicated.

Reference:

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

Clarification on Quality Control of Reagents for Antibody Screening and Identification

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Principle:

This policy is a reiteration of current policy to QC reagents used for antibody screening and identification to document how current practice meets these requirements.  This policy is NOT a change from current practice.

Policy:

  1. Each cell used for antibody detection must be checked each day of use for reactivity of at least one antigen using antisera of 1+ or greater avidity:
    1. We will use reactivity encountered during the daily antibody testing:  reactions of 1+ in each screening cell will be deemed acceptable.  For panel cells, reactions of 1+ or greater for any specificity will be deemed acceptable.
  2. Typing reagents such as anti-D, anti-K, anti-Fya, etc. must be checked each day of use.
    1. Already defined explicitly in SOPs
  3. Anti-IgG reactivity of antiglobulin reagents may be checked during antibody screening and crossmatching:
    1. Currently performed as per manufacturer’s instructions (e.g., Immunocor, Biorad, Grifols, Ortho) for gel and tube reagents.
  4. Typing sera and reagent cells must be checked for reactivity and specificity on each day of use, including a check against known positive and negative cells or antisera:
    1. Already defined explicitly in SOPs

References:

  1. Standards for Blood Banks and Transfusion Services, Current Edition, AABB, Bethesda, MD, USA
  2. Guidelines to the Preparation, Use, and Quality Assurance of Blood Components, European Committee (Partial Agreement) on Blood Transfusion (CD-P-TS), Current Edition
  3. TRM.31400, CAP Checklist, current version

Donor Unit Discrepancies

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Principle:

All donor unit mislabeling is potentially life-threatening and must be stringently investigated as soon as possible after the discrepancy is detected.  Most importantly, if there is one error, there may be possibly ADDITIONAL donor unit errors (e.g. switch of donor tubes or units, etc.).  All donor units processed in the same batch must be also quarantined until the discrepancies are resolved.

The blood bank computer system will detect many errors;  however, if the donor unit or its samples are mislabeled in the beginning, these may not be detected.  Medinfo enforces checks on the final ISBT label and will compare current results to the historical record and will alert to any errors. Additionally, the use of ISBT specimen labels will obviate the risk of barcode reading errors.

Definitions:

Responsible blood bank physician:  specialist or consultant physician on-call at the time the discrepancy is detected

Policy Details:

The following steps MUST be performed as soon as possible:

  1. The Component Processing Supervisor or Senior Technologist must be IMMEDIATELY notified of any discrepancy.
  2. The Blood Bank Supervisor will inform the Division Head, Transfusion Medicine.  If the Head is not available, notify the Transfusion Medicine on-call.
  3. Quarantine ALL donor units collected and processed in the same batch.
  4. Obtain copies of all testing including photos of the gel/glass bead cards documenting the discrepancy.
  5. Obtain copies of all worksheets used in donor processing for the affected batch.
  6. Perform repeat ABO/D typing of ALL DONOR UNITS in the affected batch.  Any further discrepancies must be investigated and resolved.
  7. Identify all staff who were involved in handling the donor unit (phlebotomist, blood bank technicians processing and labelling the unit).  Identify those associated directly with the error.
  8. Submit all documents and photos to the Blood Bank Supervisor or designate.
  9. Prepare an occurrence/variance OVA report documenting all the data, findings, and interpretations.
  10. All investigations must be reviewed by the Supervisor, responsible blood bank physician, and one of the senior consultants.
  11. All such investigations must then be finally reviewed and approved by the Division Head, Transfusion Medicine or his designate.  Only when the issue(s) are completely resolved and investigation is approved may the donor unit be properly relabeled and released into available stock.  Also, only at that time may the other units in the affected batch be released into available stock!!
  12. Photograph the correctly relabeled unit and attach it to the other documentation of the incident.
  13. If the discrepancy cannot be resolved, ALL units in the affected batch must be discarded.
  14.  The implicated staff’s personnel record should be reviewed for previous errors.   Appropriate disciplinary action should be taken and documented in the personnel record.  If a verbal warning is given, it should still be documented in the written record.
  15. If there is a systemic cause for the error, appropriate measures should be taken to minimize reoccurrence.
  16. All actions must be in accordance with the institution’s policies and regulations.

2/11/20