Now that we have automation in the transfusion service and blood bank instruments interfaced with laboratory information systems, it's time to consider adding these instruments to the core lab automation line and autoverification.
This might seem like a radical suggestion since no
automated typing and screening instrument for the transfusion service
can yet be added to an automation line and since autoverification is only
now being accepted as a standard operating procedure in other areas of
the lab. But it makes sense. Except for allogeneic stem cell transplant
patients, a person's blood type doesn't change, and negative antibody
screens predominate. Furthermore, samples requiring technologist intervention
may hold up other normal results, delaying the time that blood components
are available for the patient.
So why address this now? Because in order for instruments
and software to be interfaced in five to 10 years, blood bank and transfusion
service specialists need to start asking for such capabilities today.
Vendors want to make sure a market exists for a new product before beginning
the development process.
Federal requirements for FDA 510(k) premarket approval
of blood establishment software add to the delay in adopting new features.
Take electronic crossmatch as an example. The FDA just issued draft guidance
on electronic crossmatch, more than 10 years after the first facilities
were approved to use the technique. And LIS vendors only recently began
offering electronic crossmatch features in their software.
So we pose the question, what would it take to satisfy
you that instruments are ready for autoverification of results? For us,
the software should compare current with previous results. If the past
two times the patient has been O-positive and the patient types as O-positive
today, we feel confident the specimen and patient are O-positive. There
is no need to send the results to a technologist. Likewise, if the patient
has always had a negative antibody screen and the current specimen's results
are also negative, there is no need for technologist intervention. Just
as with hematology and biochemistry, the algorithms determine whether
autoverification is appropriate.
One caveat is that the strengths of the reactions used
by the instrument or software to determine a patient's blood type must
be controlled by the user, not hard coded by the vendor. For example,
a weakly positive (1+) result may be used by an instrument to conclude
that a patient is Rh positive, but the end user may decide that a 1+ reaction
with anti-D is not sufficient to automatically conclude that a person
is Rh positive.
Some blood bankers may be slow to embrace the concept
of autoverification because of the burden of validation. Since blood bankers,
overall, are a conservative group, many may feel more comfortable monitoring
for problems themselves. These individuals could review a daily report
of patients with positive antibody screens and typing discrepancies to
allay their concerns.
One must keep in mind that autoverification with a
hematology instrument will be different than with a blood bank instrument.
Once a hematology result is autoverified, the laboratory is finished with
it. The process is more complex for verifying a type and screen. The blood
bank may be using the sample to prepare blood components or may file it
away to be used in the future. How will the technologist know that testing
is complete and components can be prepared? For blood banks that use electronic
crossmatch, samples with one blood type need to be identified for a second
blood type. The sample would have to be located and re-tested.
To convey to instrument and LIS vendors what you want
their respective software to do, you should start documenting process
specifications. These include the goals of autoverification, the type
of results that do not need intervention, an explanation of what constitutes
a problem sample, or details of how the instrument will identify a problem
that needs technologist intervention. A process flow chart could help
define the path of a normal versus a problem sample.
Instrument limitations will continue to determine process
flow. For example, a chylous sample will influence a gel technology result
but might not be a problem with a microtiter plate. Examples of questions
that relate to process flow are, Will the repeat test be on the same instrument
or use another test method? If the instrument on the line is in another
building, and the tube is needed for additional work in the blood bank,
how will it be transported? Will the blood bank be completely paperless?
Think about process specifications now and then ask
for what you want and need for the future. In other words, ask for today
what you want tomorrow.
Suzanne Butch is administrative manager, and Theresa Downs is supervisor, Blood Bank and Transfusion Service, University of Michigan Hospitals, Ann Arbor.