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

Teaching Document: Validation Process

drzeyd

This is a teaching document for medical technology and transfusion fellows to explain the general structure of a validation.

Principle:

All validations must be planned.  A validation protocol must be prepared with specific criteria for acceptance.  All validations with attached evidence must approved by the Head, Transfusion Medicine.

Policy:

  1. A written validation protocol must be prepared in the advance and at least including the following:
    1. Specific parameters and number of iterations to be performed
    1. Designated staff to perform validation
    1. Documentary evidence of the testing
    1. Specific acceptability criteria
  2. The completed validation protocol must be submitted to the Division Head, Transfusion Medicine, or designee for review.
  3. Once the validation plan has been reviewed, it must be performed by the designated staff.
    1. Software validations will be performed in a specific test environment, not in the live, production system.
  4. The completed validation document, including screenshots of the software functionality if applicable, must be submitted to the Division Head, Transfusion Medicine for review.
  5. The equipment or software may only be used if the acceptability are met AND the validation is approved by the Division Head, Transfusion Medicine or designee.
  6. The completed validation protocol will be stored in the document control system.

Reference:

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

Bedside Monitoring of Transfusion

drzeyd

Once the blood component has left the hospital blood bank, it should be directed transported to the patient’s bedside for immediate transfusion.

At the bedside, the transfusionist (usually a nurse or doctor) must verify the information on the blood component labels (both the ISBT and specific reservation one for the patient).  With a bedside device, this includes:

  1. Scan the patient armband for hospital number
  2. Scan ISBT label:
    1. ABO/D type and any other antigen typings
    2. Blood component type (RBCs, platelets, plasma, etc.)
    3. Expiration date/time of the component
  3. Verify Reservation Label (on back of unit)— centrally performed in blood bank computer system based on #1 and #2 above:
    1. Intended recipient name and hospital number
    2. Compatibility status (compatible, least-incompatible, etc.)
    3. Expiration date/time of the compatibility testing/crossmatch
  4. Record Documentation During Transfusion:
    1. Physical inspection of the unit
    2. Time stamp of transfusion start
    3. Vital signs before starting transfusion
    4. Periodic vital signs during transfusion
    5. Time stamp of stopping transfusion
    6. Any adverse effects during the transfusion
    7. Any adverse effects after the transfusion (remote vital signs, oxygen saturation, EKG lead—if appropriate monitoring device attached to patient (e.g. Umana T1 device).

All of these parameters can be entered into a hand-held device that transmits them to the blood bank computer system (e.g. Medinfo Hemotrace.)

The Blood bank computer system (patient module) should verify that this is the proper unit for the intended recipient and that the transfusion is starting within the reservation limit of the unit and serves to verify the information on the reservation label attached on the back of the blood unit.

With a device such as  the new Umana T1 device from the GPI group, the vital signs together with an EKG lead and oxygen saturation can be automatically uploaded into the handheld device that feeds into the blood bank computer system such as Medinfo Hematos IIG and/or directly transmitted to the blood bank software.  This device can continuously record this information for several days and detect post-transfusion adverse effects such as TRALI/TACO and delayed hemolytic transfusion reactions.

Note:

Some other nursing hand-held devices are available for recording patient data but many cannot read the ISBT unit number or descriptor information.  They also do not check with the blood bank computer system to check if the right unit of blood is being offered to the patient during the validity of the transfusion period (four hours after leaving the blood bank).

Washed RBCs

drzeyd

Note:  This is an updated version of a previous post.

Principle:

Washing RBCs removes plasma and reduces the leukocyte count only by 1 log.  For leukodepletion, we must rely on filtration to reduce the WBCs to less than 1 x 106 per unit according to CE rules.  Red cells or platelets in additive solution contain only minimal plasma (about 35 ml).  There are few definite indications for washing RBCs and it should be rarely necessary.

Policy:

Washing RBCs should only be done in the following circumstances:

  1. Deglycerolization of frozen RBCs.
  2. Severe allergic or anaphylactic reactions to plasma proteins
  3. IgA deficiency with anti-IgA
  4. Paroxysmal nocturnal hemoglobinuria PNH—relative indication (often these patients receive RBCs before the diagnosis of PNH is confirmed)
  5. Transfusing a previously irradiated RBC unit for pediatric use if more than 24 hours has passed since it was irradiated.
  6. Any other time when so designated by a transfusion medicine consultant.

Note:

  1. If anyone requests washed RBCs and it does not fit into one of the above categories, contact the transfusion medicine consultant.
  2. Washed RBCs are NO substitute for leukodepleting RBCs by filtration NOR can they be used in place of irradiation for prophylaxis against transfusion-associated-graft-versus-host disease TAGVHD.  Using the Reveos automated component processing system, all components are leukodepleted—RBCs are released in SAGM.

Reference:

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

Opinion: Ready after Fellowship?

drzeyd

I was recently interviewing a candidate for consultant in Transfusion Medicine.  Several months previously he had completed a fellowship in Transfusion Medicine in the United States.  He was applying for a position in my hospital in Qatar, which included seven hospitals and a blood donor center.  He had no training in donor management or therapeutic apheresis.

The successful candidate was to rotate on-call to cover all hospitals and the blood donor center.  He had never worked outside the United States.  Routinely, he did not review antibody panels since those workups were usually sent to the local blood provider there.  In his training, he had strictly followed US FDA and American version of AABB Standards.  His training center did not routinely do extended phenotypes (C, c, E, e, and Kell).  Extra testing and phenotyping had to be explicitly ordered by the clinician to get reimbursement.  Thus, there was no prophylactic antigen matching done on patients.  He did not feel comfortable reviewing antibody panels.

He had no experience with universal leukodepletion, pathogen-inactivation, platelet additive solutions, or automated component production such as the Terumo BCT Reveos.  He did not interpret donor marker testing results.

On the contrary in our organization, the transfusion medicine physician had to review all antibody panels (usually he was the most knowledgeable person for this).  We followed the Council of Europe CE and other practices that did prophylactic antigen matching.  We were also in charge of donor qualification and therapeutic apheresis and reviewed any product deviations from the Reveos and donor marker testing.

Clearly, this candidate did not practice transfusion medicine in the way that was necessary for our operations.  We could not cut him loose and make him responsible for a hospital transfusion service or the blood donor center.

Let us contrast this candidate for one being recruited for anatomic pathology/histopathology.  Grossing specimens, performing frozen sections, reading slides, diagnosing cases are the same everywhere in the world.  After completing his American certification, he could perform his profession almost anywhere in the world.

Transfusion medicine practices need to be localized and the selection of blood components and donor qualification are different.  Most of the world does not follow US FDA and has access to blood components, tests, and other technology that is different and maybe more advanced than his training in the USA.

I gave him a clinical scenario to interpret.  An AB patient with anti-K needs to be transfused with plasma.  Are there any special requirements for the plasma?  What if the only AB donor had anti-K would you use it?  What if the only RBCs available had not been phenotyped for Kell?  What would you do?

He did not know that we discard plasma with clinically significant alloantibodies routinely.  He did not want to phenotype the RBC unit for this patient since this had not been explicitly ordered by the clinician.

My recommendation was not to hire this candidate if there were others who had worked in European or similar systems to our own practices.  In effect, to use this physician, he would have to undergo a mini-fellowship to learn our practices since they were contrary to ours.  Unfortunately, we were very short-staffed and did not have resources to offer this training.

In summary, blood bank practices are very localized.  If you are considering to hire staff from other countries not following your standards, you must assess if the candidate is flexible to change his practices and/or whether you have the resources to train the physician.

Clinical Significance of a Negative DAT

drzeyd

In my opinion, the direct antiglobulin test is the most important concept that a transfusion medicine physician or technologist must understand in interpreting complex serology patterns.

Like all other testing, the DAT must not be interpreted alone but rather in the context of other laboratory and clinical results.  Still, it is very important to understand the significance of the DAT in hemolysis.

The mere presence of immunoglobulin on the RBC surface does not necessarily mean severe hemolysis.  The DAT strength increases with increased immunoglobulin coating of the RBCs but does not necessarily indicate how quickly the RBCs will be cleared.  That depends on the class and subclass of the antibody, whether and if so, how avidly it fixes complement, etc.

One trick question I give in my lessons to staff is, “What is the clinical significance of a negative DAT?”

In my career, I have seen severe hemolysis with either negative or weak DAT, the latter especially if there is weak C3 staining.  The DAT can be negative because there is no significant antibody OR there is a highly destructive antibody causing massive hemolysis, leaving only the antigen-negative cells (and in that case, there is still the possibility of innocent bystander hemolysis).

I show them the following case of an ABO-incompatible acute hemolytic transfusion reaction:

OLYMPUS DIGITAL CAMERA

In this case, a group A patient received a group B RBC unit intended for a patient with a similar name who was group B and was in a bed next to him.

Notice the patient’s complete loss of the reaction to group B cells in the reverse type and the supernatant hemolysis.  The DAT was negative.  The transfused B cells were not even present in the post-transfusion gel.

Here is the urine specimen from that case showing gross hematuria:

OLYMPUS DIGITAL CAMERA

So, in severe, life-threatening hemolysis, even antibody-mediated, you may have a negative DAT.  DAT negativity may also be seen in non-immune hemolysis.  I will discuss causes of DAT-negative hemolytic anemia is a future post.

In summary when doing a hemolysis investigation, a negative DAT does not mean everything is all right.  Everything must be interpreted in the context of the clinical and other laboratory findings.

Specifications for the CCP Blood Bank-Hospital Information System Interface

drzeyd

At HMC Doha, we had a limited bidirectional interface between Medinfo Hematos IIG blood bank software donor and patient modules and the hospital information system HIS Cerner Millennium for blood component and limited blood bank testing ordering and return of the blood component ordering statuses and all blood bank test results.

For the purpose of COVID Convalescent Plasma CCP, the following specifications applied:

  1. Ordering of CCP was either by number of units (average 220 ml each) or volume in ml (up to 200 ml).
    1. Maximum order was 2 units.
  2. Only designated physicians could order CCP.
  3. A valid type and screen (72 hour maximal validity) had to be in effect to place an order for CCP.
    1. If not valid, a new type and screen must be ordered before ordering CCP.
  4. Selection of the ABO type of CCP was at the discretion of blood bank using its standard algorithms.
  5. Status of order (ordered, received in blood bank, in process in blood bank, or released) would show in the HIS.

Note:  Bedside documentation of the component transfusion was the NOT the responsibility of Transfusion Medicine or Medinfo Hematos IIG.

DAT-Negative Hemolytic Anemias

drzeyd

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

drzeyd

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.