Month: Aug 2020

Time: Appreciating How Long Testing Takes

drzeyd

I have had many medical students, residents, and fellows rotate through my Transfusion Medicine department.  Hardly anyone has had any interest in making my discipline his/her career.  It is a required rotation or an “easy” rotation during which the trainee may take his vacation.  The trainee will cram for the examination and then promptly forget it.

I left practice in the USA in 1990, in what I consider the golden age of laboratory medicine.  We had supervisors for each laboratory section.  In the blood bank, we had many staff with SBBs or who were SBB students.  We were very self-sufficient in handling immunohematology problems except for rare blood types or antibodies to high incidence/prevalence antigens.

When I returned to visit my old laboratory.  I sensed a deprofessionalization of the laboratory and blood bank in particular.  Blood Bank now is a cost center, not an area of revenue.  Why hire experienced blood bankers for most hospitals?  Send the antibody workups to the Blood Center.  There are limited jobs for transfusion medicine consultants.  Minimize testing, don’t do extended antigen typings, etc.

Nowadays, I feel like one of the dinosaurs marching into oblivion as in Walt Disney’s Fantasia film, the section called The Rite of Spring.  Who will replace those of us retiring?  Have you ever noted the average age of attendees at the AABB annual convention?  I feel young when I go there (and don’t worry about the gray hair!)

I want to attract new doctors and scientists to Transfusion Medicine.  I really try, but most have no interest and look on their rotations as a necessary evil.

I have lowered my expectations for most medical trainees in Transfusion Medicine.  They don’t like it, they just want to pass it, and move on.  What must I impress them with for their future careers?  What is essential for them to remember?

I have had both pathology and non-pathology trainees.  Surgical and ob/gyn doctors used to spend one month whereas the hematology and pathology residents/fellows spent on average three months.  The few interested in the field might do multiple rotations.

I still gave them lectures on a variety of topics, especially how to transfuse blood components, basic ABO/Rh antigens, compatibility testing, and direct antiglobulin testing.  They would forget most of this, but I wanted them to remember TURN-AROUND-TIMES:

How long does it take to perform the test?

Find compatible blood?

Thaw the plasma?

Release a massive transfusion protocol shipment?

Complete a transfusion reaction workup before releasing more blood?

I am not discouraging people from entering the field, but I am a realist to know that few will share my passion for serology or want to take call on difficult immunohematology cases.  At least if they understand the pressure the technical staff are in and these turn-around-times this will make both their work as clinicians and mine as transfusion medicine more congenial.

Processes and Software Building 26: Donor Collection 4

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Deferral Intervals for Each Donation Type

Donation can be whole blood or apheresis-based.  The sex and age for each donation type is specified.  At HMC, we did not accept females for platelet or plasma donations, so the starting age is listed as 99 years.  Otherwise, in accordance with Qatari law, the starting age for donation is 18.  All these parameters are user-definable, and a transfusion medicine physician can override the rules if necessary.

For each and every combination of donations, the deferral interval must be specified.  Examples follow.  The temporary deferral period is in days:

Previous donation whole blood, current donation whole blood:  56

Previous donor platelets, current donation whole blood:  2

Previous donation whole blood, current donation platelets:  56

Also note how for each possible combination there is an entry for male AND female.  Females are restricted to whole blood donation and only RBCs will be made from the collection.

If there is a collection incident and the apheresis procedure is not completed, the interval will be set to 56 days.  This will be covered in the post on donor adverse effect reporting.

To Be Continued:

3/8/20

Daratumumab Anti-CD38 Interference with Compatibility Testing

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Principle:

Daratumumab is a monoclonal antibody that binds to CD38 antigen, which is expressed weakly on the surface of all RBCs.  It may thus cause a positive direct antiglobulin test DAT and so interfere with compatibility testing if an antiglobulin phase is required.

This effect may persist up to 6 months after discontinuing the drug.  The monoclonal antibody does not interfere with routine ABO/D typing.

Special techniques (neutralization of CD38 antibodies by CD38 anti-idiotypic antibodies, or soluble CD38 antigen) may remove the panreactivity but are not generally available.  DTT, a sulfhydryl reagent may denature the native CD38 antigen on RBCs but it should be used under a biologic hood.

Kell antigens will be denatured so Kell antibodies cannot be detected after treatment so Kell-negative RBCs should be used.  In the Gulf Area, this is about 72% of RBCs. In the Medinfo software a rule to require K-negative RBCs has been built.

Policy:

  1. The clinical services must inform Transfusion Medicine of patients who will be receiving daratumumab therapy BEFORE treatment is started.
  2. Transfusion Medicine staff will enter a general comment (i.e. not associated with a particular result) in the patients Medinfo HIIG record:  PATIENT ON DARATUMUMAB.
  3. If not already done, Transfusion Medicine staff will perform an extended antigen typing:  at least C, c, E, e, K, k, Kpa, Jka, Jkb, Fya, Fyb ,M, N, S, s, Lea, Leb, P1—even if no antibodies are currently identified.
  4. Transfusion Medicine staff will send each such patient’s record to a Transfusion Medicine Physician to determine the blood type including extended antigens to match for future transfusions.
  5. When compatibility testing is requested, perform it as per our SOPs.
  6. If available, prepare DTT-treated cells for testing but realize that this will denature Kell antigens.  Use K-nell RBCs.
    1. Medinfo has a rule to automatically require K-negative RBCs if this medication is used.
  7. Release least “incompatible” RBCs must be approved by the Transfusion Medicine Physician.
  8. When the DAT becomes negative (i.e. up to SIX months after cessation of Daratumumab therapy), routine compatibility testing and RBC selection will apply.

References:

Trick or Treatment, Anti-CD38 Reactivity and How to Treat It, AABB Satellite Symposium transcript, U. Cincinnati and RedMedEd, October, 2015 (attachment)

Processes and Software Building 25–Donor Collection 3

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Donation Type and Bag Parameters

At the time of registration, the type of donation must be specified.  In my last position, this could include whole blood for automated Reveos, whole blood for cryoprecipitate, plasmapheresis, COVID 19 convalescent plasmapheresis, plateletpheresis, concurrent platelet and plasmapheresis, concurrent platelet, plasma, and RBC apheresis, RBC apheresis-one unit, and RBC apheresis-2 units.

There is also a specimen-only donation without actual collection that includes database check, assignment of an ISBT specimen number, donor questionnaire, physical examination, and specimen collection only..

We specified which bag or kit could be used for each type of donation so when it was selected, only that bag type would be accepted by Medinfo

For each of these types we must specify what type of donation is permitted:  volunteer, autologous, or directed.

Finally, we must indicate the maximum length of the procedure permitted.  This applied to whole blood only and we set this at 15 minutes—this is user definable.

The following are a sample set of parameter settings for the above:

Note how we included contingencies for old bag sets and equipment (that we later discontinued) and for granulocyte collection (which we did not actually perform).

To Be Continued:

1/8/20