Month: Sep 2020

Projective Exercise 8

drzeyd

As a transfusion medicine physician, I must know if I can trust my staff’s interpretation of immunohematology testing.  I may be called at night and they will provide me with results and I must use these to make a medical judgment.  If their interpretation is flawed, I might make a decision that harms the patient.

I really don’t like multiple-choice questions, but nowadays this is often the norm.  For my staff, especially senior staff and those who want to be promoted to senior staff, I have developed a series of projective exercises to help me understand their thought processes.  I emphasize that I do not want a mere regurgitation of isolated facts:  I want integration of the facts into useful information!!

The following is my favorite assessment, offered to advanced staff and candidates for senior technologist, supervisors, and technical manager positions.  Usually, these staff have SBB, ART, FIBLS or equivalent qualifications.

You are reviewing abnormal test results and receive the following case:

Anti-A:           4+

Anti-B:           0

Anti-A,B        4+

A1 cells         0

B cells           3+

Anti-D            3+

D-control      0

Antibody Screen:  3+ in SC1 (R1R1), 4+ in SC2 (R2R2), 0 in SC3 (rr)

Antibody Identification:  Anti-D

Give possible explanation(s) for this situation.  Request any additional information you need.

What blood type will you transfuse?

Solution will follow in a subsequent post.

30/9/20

Direct Antiglobulin Test and Selection of RBC Units for Transfusion

drzeyd

Principle:

In 1984 effective with the 13th Edition AABB Standards, the requirements for performing a direct antiglobulin test and autocontrol for compatibility testing were eliminated.  The DAT is very important to detect delayed hemolytic transfusion reactions, certain autoimmune conditions, and drug-related hemolysis.

Since that time, the immediate-spin crossmatch and now the electronic computer paperless crossmatch may be used for most compatibility testing in place of the classic, antiglobulin-phase (indirect antiglobulin test) crossmatch.

If an antiglobulin phase (IAT) crossmatch is performed, an RBC unit with a positive DAT will cause a false-positive reaction.  Since most crossmatching does not include the IAT, it will not be affected by the DAT status of a donor unit.

Policy:

  1. Donor RBC units will NOT be routinely tested for DAT as part of component processing.
  2. The type of compatibility testing selected for a particular patient should be the technically simplest one (no need to do extra work unless so instructed by the transfusion medicine consultant/designate):
  3. Do a full antiglobulin-phase IAT crossmatch if ANY of the following applies:
    1. There are no two independent ABO/D typings on the patient during the current admission.
    2. The ABO/D type of the current admission does not match the historical information.
    3. The patient has a detectable antibody at 37C
    4. The patient has a history of a clinically significant antibody but no current antibody
    5. Whenever the consultant, transfusion medicine/designate requests it.
    6. Whenever the Medinfo HIIG record so indicates (in comment section)
  4. Do the immediate-spin crossmatch if ALL of the following apply:
    1. Only one determination of the ABO/D type
    2. The historical ABO/D type agrees with the current type.
    3. There are no antibodies reacting at 37C AND there is no history of antibodies at 37C.
  5. Use the computer/electronic crossmatch if ALL of the following apply:
    1. There are two determinations of the ABO/D type and they both agree with each other.
    2. The historical ABO/D type agrees with the current type.
    3. There are no antibodies reacting at 37C AND there is no history of antibodies at 37C.
  6. When to do a DAT on a donor unit:
    1. Patient antibody screen is negative but the full AHG crossmatch is incompatible.
    2. Part of a transfusion reaction workup where the AHG crossmatch of donor cells and patient serum is incompatible.
    3. Whenever the consultant, transfusion medicine/designate requests it.
  7. If a donor unit is found with a positive DAT:
    1. Test with polyspecific and monospecific IgG and C3d antisera
    2. Perform an acid-elution.
    3. Send the results to the transfusion medicine consultant/designate for review.
    4. The reviewer will enter his review in HIIG in the Donor Consultation Section both as global donor comment and a result-specific comment against the antibody screen result.
    5. Use of the DAT-positive donor unit:
      1. Select another RBC unit for the transfusion.
      2. The final decision to use the unit will be made by the Transfusion Medicine consultant/designate.

Important:  Don’t do a classic AHG/IAT phase crossmatch unless you have to do it  (see conditions above.)  A donor unit with a DAT is unlikely to be clinically significant and may be transfused safely to the patient in most situations.  Patients receiving electronic-crossmatch and immediate-spin crossmatch are receiving units with positive DAT without incident.

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. Technical Manual, Current Edition, AABB, Bethesda, MD, USA

Processes and Software Building 48: Donor Immunohematology Testing

drzeyd

Donor immunohematology testing of components in progress is similar to patient immunohematology testing.  The tests include:

ABO forward and reverse testing

D typing by multiple monoclonal cocktails

ABO/D confirmatory testing

Antibody screening

Antibody identification

Truth tables are prepared for each test type with interpretations.  Results falling outside these ranges will require manual review and manual interpretation by a user with an appropriate level of privilege (usually senior technologist, supervisor, or transfusion physician.)

Unlike patient D typing, we want to detect partial or variant D types as D-positive since theoretically even a few epitopes of D present may be immunogenic to the patient.  In patient D typing, we can call partial D types as D-negative and use D-negative RBCs.  We don’t want to use partial D RBCs for D-negative women of child-bearing age!

This series will show several different test algorithms including both manual and automated methods.  The criteria for acceptability of the reactions are based on the manufacturers’ recommendations. 

Reflex ordering of antibody identification will occur if the antibody screen is non-negative.

28/9/20

Donor Center Materials and Equipment Strategy

drzeyd

This is the policy I developed for HMC Doha Blood Donor Center:

Policy:

  1. This policy applies to all blood donor processing (including reagents, materials, equipment) in the Blood Donor Center.
    1. Immunohematology testing and donor infectious disease marker testing are not included.
  2. Equipment and reagents must be selected to meet/exceed productions standards set by the Council of Europe, International AABB, HMC policies and procedures, and Qatari law.
  3. Each equipment must have a fully functioning, reliable, bidirectional interface to Medinfo Hematos IIG and be fully interfaced
    1. Vendor is responsible to pay for the interface licensing for each piece of equipment.
  4. Materials/reagents/equipment must cover the following functionalities:
    1. Automated separation of whole blood and apheresis components into:
      1. Packed RBCs in additive solution
      2. Buffy coat derived platelet pools
      3. Apheresis-derived platelets, plasma, and/or RBCs
      4. Fresh frozen and FP24 plasma
    2. Pathogen inactivation of whole blood, platelets, plasma, RBCs
    3. Cryoprecipitate
    4. Cryo-poor plasma
    5. Frozen RBCs (high-glycerol method)
    6. Washed RBCs
    7. Thawed plasma
    8. Irradiated RBCs
    9. Reconstituted whole blood (PRBCs and thawed plasma)
    10. Leukodepletion of ALL components to current and future CE standards
  5. Equipment must have/meet:
    1. CE mark or equivalent (FDA, CSA, etc.)
    2. Sufficient throughput for the workload in the area assigned
    3. Scalability:  A path of upgrading to larger capacity/throughput equipment using the same reagent line of the vendor
    4. A minimum of two of each equipment type must be obtained to minimize disruption of blood supply.
  6. Vendors:
    1. Vendors must offer 24/7 service on critical equipment for donor blood component and patient compatibility testing
    2. Vendors who do not meet qualification standards must not be used.

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 (CD-P-TS), European Directorate for the Quality of Medicines and Healthcare, Current Edition, Strasbourg, France

Opinion: Selecting a Site to Assess a Candidate Software

drzeyd

You have already sent out an RFP (request for proposal) for a laboratory software and have received several responses.  Regardless what the vendor provides, you need to contact a comparable site to your own and assess how well the solution is working.

The key word is COMPARABLE.  The site should have similar functionality (breadth of test and process menus), test and activity volume.  If you have multiple sites, does the candidate site have the same?

Technically, to assess response time, you should select a site that uses the same platform (e.g. Microsoft SQL Server, Oracle, etc.) and operating system (Windows, Linux, UNIX, etc.)

At one institution I worked at, they went on a site visit, but it used the software on a different platform (UNIX). They wanted to use it on Microsoft SQL Server.  They were happy with the observed response times during the visit, but when they installed it on their chosen platform, it was very slow.  You cannot compare an apple to an orange (or in this case to a prune).

I would ask to speak to key players at the site visit without the vendor being present.  Hopefully, they will be honest with you about their experiences.  I was once very surprised that I was asked to allow for a site visit for a non-blood bank software for which I had serious concerns.  I would not serve as a site visit.

26/9/20

Re-Entry of Donors with History of Hepatitis On/After Age 11

drzeyd

Principle:

Until this guidance, everyone with hepatitis at age ≥ 11 has been permanently deferred, regardless of the type of hepatitis.  Except for confirmed cases of HCV at any age, donors with other causes may be reassessed to determine if they may be re-entered into the donor pool.  I have also included assessing levels of anti-HBs as per my previous policy at HMC Doha.

Policy:

  1. All donors with a history of HBV (confirmed HBsAg and/or HBV-NAT positive) or HCV, regardless of the age it occurred, continue to be permanently/indefinitely deferred.
  2. Donors with anti-HBc with negative HBsAg and/or HBV-NAT may be further assessed by performing anti-HBs titering.
    1. If the level of anti-HBs >= 100 IU/L (mIU/ml), then the donor may be reentered.
    1. If the donor’s antibody titer < 100 IU/L, he may be offered HBV vaccination:
      1. If the post-vaccination HBV titer >= 100 IU/L, then he may be reentered.
      1. If the donor does not receive HBV vaccination, he remains deferred.
  3. Donors with a history of HAV, CMV, or Epstein-Barr hepatitis may be reentered into the donor pool without further testing.
  4. If the donor is uncertain what type of hepatitis he had, then perform:
    1. HBV testing (HBsAg, HBcAb, HBsAb, HBV DNA NAT)
    1. HCV testing (HCV Ab, HCV LIA, HCV RNA NAT
    1. Liver enzyme testing (ALT, AST)
  5. If there is evidence of current or past HBV and/or HCV, then the donor is still permanently deferred
  6. If there is evidence of ALT or AST elevation, the donor remains indefinitely deferred.

References:

Requalification of Donors Previously Deferred for a History of Viral Hepatitis after the 11th Birthday, FDA-2017-D-5152–Requalification for History of Hepatitis Guidance-Final, US FDA/CBER, September 2017

Processes and Software Building 47: Apheresis Plasma

drzeyd

At HMC during my tenure, all plasma products—whole-blood and apheresis-derived were pathogen inactivated with riboflavin (Mirasol).  In our software processes, I had options to release both Mirasol-treated and untreated (the latter in emergencies) and to aliquot either as needed.  The same processes applied to COVID-19 convalescent plasma CCP except that they were performed in a quarantine production area.  There were specific ISBT codes for CCP.

24/9/20

Projective Exercise 7

drzeyd

As a transfusion medicine physician, I must know if I can trust my staff’s interpretation of immunohematology testing.  I may be called at night and they will provide me with results and I must use these to make a medical judgment.  If their interpretation is flawed, I might make a decision that harms the patient.

I really don’t like multiple-choice questions, but nowadays this is often the norm.  For my staff, especially senior staff and those who want to be promoted to senior staff, I have developed a series of projective exercises to help me understand their thought processes.

Here is another exercise for ABO discrepancies.  I offered this to senior technologist and supervisory candidates:

Can they name the conditions that give these results?

23/9/20

SARS-CoV-2 Vaccines and Donor Qualification

drzeyd

Principle:

Under AABB and FDA rules in the Uniform Donor History Questionnaire, unlicensed, investigational vaccines have a 12-month deferral or as indicated by a responsible physician.  In light of the anticipated vaccination trials for COVID-19, this policy gives interim guidance until more definitive information is available.

For COVID-19 Convalescent Plasma CCP donation, investigational vaccine recipients should not donate COVID-19 convalescent plasma until further information is available about their antibody profile.

Policy:

Any donor who has received a COVID-19 (SARS-CoV-2) vaccine will be deferred as follows:

  1. Whole blood or apheresis donation (except COVID-19 convalescent plasma):
    1. Live, attenuated vaccine:  14 days post vaccination
    2. Non-replicating, inactivated, or RNA-based vaccine:  NO DEFERRAL
  2. COVID-19 Convalescent Plasma CCP Donation:  DO NOT ACCEPT

Reference:

Text from the AABB Weekly Report:

Novel Coronavirus Update, Regulatory Update:  Investigational Vaccines and Deferral for Donor of Blood and Convalescent Plasma, AABB Weekly Report, 7 August 2020

“FDA recognizes AABB’s DHQ which includes unlicensed (experimental) vaccines on the medication deferral list as a 12-month deferral or as indicated by the responsible physician.

“For routine blood donation, the responsible physician may wish to consider the potential infectious risk associated with the vaccines, and the use of short deferral periods (e.g., 14 days) for live attenuated vaccines and no deferral for non-replicating, inactivated or RNA-based vaccines.

“We agree that no deferral is necessary for routine blood donors who might have received the mRNA-1273 Moderna vaccine.

“At this time, we suggest that individuals who have received a COVID-19 investigational vaccine should not donate COVID-19 convalescent plasma until further information is available about their antibody profile.”

Projective Exercise 6

drzeyd

Projective Assessment Exercise 6

Zeyd Merenkov, MD, FCAP, FASCP

Independent Consultant in Transfusion Medicine

As a transfusion medicine physician, I must know if I can trust my staff’s interpretation of immunohematology testing.  I may be called at night and they will provide me with results and I must use these to make a medical judgment.  If their interpretation is flawed, I might make a decision that harms the patient.

I really don’t like multiple-choice questions, but nowadays this is often the norm.  For my staff, especially senior staff and those who want to be promoted to senior staff, I have developed a series of projective exercises to help me understand their thought processes.

Here is another exercise using elution:

Will they know to get the medication history?  What are the mechanisms by which a drug may cause a positive DAT?

21/9/20