In two settings, plusses pile up for POC coag testing
perfect clinical world, surgeons could obtain a patient’s
coagulation test results as fast as they do their hemostats to control
bleeding. And patients in Coumadin clinics would get their anticoagulation
adjusted the instant their INR slipped out of therapeutic range.
In the real
world, point-of-care coagulation testing and treatment algorithms
are as close as it gets to that imaginary ideal, though everyone
agrees the POC devices are far from perfect. Yet a growing number
of studies show that the point-of-care approach appears to produce
impressive clinical and cost outcomes in cardiac surgery and outpatient
turnaround time for coagulation tests guides surgeons in controlling
surgical bleeding and in avoiding unnecessary blood transfusion,”
says Haifeng Mark Wu, MD, assistant professor of pathology and director
of the clinical coagulation laboratory at Ohio State University,
Columbus. Dr. Wu’s laboratory is considering using POC coagulation
testing for cardiac surgery and organ transplantation in its new
Ross Heart Hospital. “Without POC values, over-transfusion
tends to occur in surgery,” he adds. “And everyone understands
the importance of saving blood. Not only are blood components invaluable
products that cost our hospital alone $10 million a year, it’s
best for patients to avoid unnecessary transfusions.”
testing helps reduce blood transfusion because it gives surgeons
the information they need to determine the etiology of bleeding
during the procedure and in the immediate post-op period. “Microvascular
bleeding is a clinical, visual diagnosis,” says David Jobes,
MD, professor of anesthesia at Children’s Hospital of Philadelphia
and the Hospital of the University of Pennsylvania, also in Philadelphia.
“You look at a wound surface and make a judgment: Is that
a discreet vessel bleeding? If not, your eyes cannot tell you anything
else except it’s abnormal bleeding.”
So what did
surgeons do before POC coagulation tests? “In a sense, clinicians
used open-heart patients to test heparin dosing until the early
1970s, when they adopted activated clotting times as the first point-of-service
test to monitor heparinization during surgery,” Dr. Jobes
become a standard POC test during cardiac bypass surgery,”
he adds. “People don’t always think about it in those
terms, but that’s what it is. And the reason it’s done
POC is that no laboratory test could help us manage the patient
in a timely manner. With the huge dose of heparin administered,
all of the lab tests would be blown out of the water, and the turnaround
makes using the lab impossible.
the point of point-of-care testing—you get the test results
in proximity to the problem, when you don’t have the option
of treating a patient without just guessing what to do,” Dr.
The data are in
Outcomes data are beginning to quantify just how well activated clotting times
and other POC coagulation tests curtail transfusion and the need for re-operation.
A study performed
by Dr. Jobes and his colleagues at the University of Pennsylvania
Medical Center found that POC coagulation testing performed during
cardiac bypass virtually eliminated return to the OR for wound exploration
due to nonsurgical coagulopathic bleeding. “And where bleeding
was treated with blood products, the need for cryoprecipitate was
markedly reduced,” Dr. Jobes tells CAP TODAY. The study’s
findings were presented at the National Academy of Clinical Biochemistry’s
second point-of-care symposium last year.
employed a combination of platelet counts (using a slightly smaller
version of a standard cell counter, the Abbott Cell-Dyn 1400), prothrombin
time test, and activated partial thromboplastin time test. “All
of the POC testing,” says Dr. Jobes, “was done in the
OR suite in conjunction with a patient-specific heparin dosing system
and verification of the reversal of heparin with a thrombin time
and a heparin-neutralized thrombin time” — all International
Technidyne Corp. devices.
Once Dr. Jobes
was certain the cardiac bypass patients had no residual heparin
in their blood, he would order a PT, APTT, and platelet count. Depending
on the test results, the surgical team treated patients before they
left the operating room. Once patients left the OR, they received
routine ICU testing: a lab-based PT, APTT, fibrinogen, and platelets.
But before patients
went to the ICU, all the testing was done outside the OR complex
by a POC lab 20 feet away, “if you can call what we had a
lab,” Dr. Jobes says.
it on a small cart with four wheels. The instruments that use whole
blood are quite small—only one is big, and that’s the
platelet counter, which is now the size of a cardboard box, 2.5
by 2.5 feet.” (Many operating rooms use Plateletworks by Helena
Laboratories at the point of service to assess platelet count and
of the University of Pennsylvania Medical Center study, which looked
at patients receiving point-of-care testing from June 1994 to May
1996, are in sync with those of other randomized trials: POC coagulation
testing pays off for patients. For example, in 2001 Mayo Clinic
conducted a pilot using a POC testing algorithm for open-heart surgery
that resulted in a 60 percent reduction in the number of patients
with excessive microvascular bleeding who received platelets, fresh
frozen plasma, and cryoprecipitate, alone or in combination. The
study is reported in Anesthesia (Nuttall GA, et al. 2001;
94: 773–781) and CAP TODAY (Titus K. 2001; 15: 22–26).
now does activated clotting times during the bypass to monitor heparin
levels. Its post-bypass algorithm includes platelets, PT, APTT,
a thrombelastograph (TEG hemostasis analyzer by Haemoscope Corp.),
and fibrinogen. “TEG and the PT and APTT are done POC,”
says Paula Santrach, MD, co-director of clinical laboratories at
Mayo Clinic and a member of the CAP Point-of-Care Testing Committee.
“We have to use fresh whole blood, so the testing has to be
close.” Platelet counts and fibrinogen are done stat in the
lab removed from the OR, but the turnaround time is still about
five to 20 minutes.
The TEG monitors
the “thrombodynamic properties” of blood by getting
it to clot in an environment that mimics sluggish venous flow, according
to the manufacturer.
surgery, we do the PTs and APTTs [using a POC device], which takes
about five minutes,” Dr. Santrach says. “The TEG system
takes 15 to 20 minutes to get a partial tracing, and 60 minutes
for a complete tracing.”
the case for savings
The clinical benefits of POC coagulation testing during surgery
are replicable and dramatic. But you have to look at the big picture
to see the cost savings. “That’s because if you just
compare the cost per test, the POC is more expensive than doing
the tests in the lab,” Dr. Santrach says.
Dr. Wu concurs. “The POC reagent is expensive, and generally
more so than in the lab because the volume of POC testing is low.”
And QC, he notes, must meet CAP accreditation requirements. “Also,
one needs to have a computerized interface between the POC instrumentation
and the hospital laboratory information system,” he says.
(The latter is not a CAP Laboratory Accreditation Program requirement.)
Yet the savings
become obvious when you compare the cost of POC coagulation testing
to the cost of blood products and return visits to the OR. For example,
Dr. Santrach says, the cost of the tests Mayo Clinic does in its
algorithm for open-heart surgery patients is lower than that of
a unit of red cells—and much lower than the cost of six units
of platelets or two units of fresh frozen plasma.
testing in the OR is cost-effective, and more so when accompanied
by a treatment algorithm, Dr. Jobes says. “The problem is
... you can get into the ‘no, not my budget’ infighting
when dealing with the cost center to which you want to attribute
the expense. So you can end up going round and round until you find
someone to agree to adjust budgets on both sides.”
with lack of standardization
On the clinical side, variability in test results among various
devices remains a challenge. This lack of standardization stands
in the way of developing a universal or standardized algorithm for
managing patients during surgery.
the devices aren’t standardized, how could one standardize
the transfusion triggers?” Dr. Santrach asks. “They
tried to [standardize] PT by using the INR, but there’s experience
that shows that even that doesn’t correct for all the differences.
In addition, there’s no way to standardize the APTT.”
Medical Center, West Virginia, found a tremendous difference in
the amount of heparin the surgical team administered during cardiac
bypass when it changed to the Bayer Rapidpoint Coag analyzer. Using
the Bayer device to monitor heparin therapy in cardiovascular surgery,
the team administers, on average, 10,000 fewer units of heparin
per procedure than it did with its previous machine. “We have
also seen less bleeding and less need for blood products with the
new machine,” says Jason Newsome, lab technical specialist
in cardiovascular perfusion at the medical center.
for such a difference in ACT results? “The various types of
ACT are subject to variability due to dilution and temperature of
the blood,” Dr. Jobes says. “And smaller volumes used
in the test systems produce less variability secondary to those
testing, normal range varies markedly from one reagent vendor to
another, agrees Bayer spokesperson Jan Price. In fact, Bayer typically
discusses with its customers up front the need for the hospital
to do studies that correlate the APTT point-of-care test with the
lab APTT test. If the normal ranges are different, the hospital
should change the reporting sheet for normal ranges.
vendor has a different range that may [vary] from what’s used
in the lab,” Price cautions. “They correlate, but they
don’t match. That’s one of the biggest educational hurdles
to using POC coagulation tests. Most vendors will help the hospital
determine the correlation and normal ranges.”
of course, would prefer to have a test that matches what they’re
doing. But just as no two labs match each other on the same tests,
no POC testing for coagulation matches directly to the laboratory’s
testing for PT and APTT. And there is no similar lab device for
With ACT, you
have to compare one vendor to the next, and in most cases they don’t
match. Even multiple instruments provided by a single vendor won’t
provide matching test results, according to Price. “The results
are different enough that you want to set up ranges,” she
says. “And the user just has to understand that the test results
correlate but don’t match, so you have to set up normal ranges
and different target times from device to device. You can’t
just come out and say, ‘Shoot for a 500 [seconds] every time
for ACTs,’ because each vendor may be different.”
confronted the practical reality of variability among devices when
its POC instrument for PT and APTT testing was temporarily recalled
by the manufacturer. Since the open-heart surgery team uses the
PT and APTT for transfusion triggers, switching to a different piece
of POC equipment would have required Dr. Santrach to revalidate
the triggers and probably change them to match the previous ones.
She decided against it. “We would have had to run things in
parallel with fresh samples from real patients, which meant a good
six-month project, and we were told we would probably get the POC
equipment back by then,” she says. In the meantime, the laboratory
is running the PTs and APTTs for the cardiac surgery team.
just say you will [take action] at the upper limit of normal because
that’s going to vary from one device to another—that’s
really the underlying issue,” Dr. Santrach says. “And
once you start switching instruments and reagents, you can get quite
different results. And the upper limit of normal may not be a good
transfusion trigger, as patients may have abnormal results but no
Whether or not
the patient is bleeding is a trigger in and of itself, agrees Charleston
Area Medical Center’s Newsome. A patient may have a functional
platelet count of 30,000, with the key word being functional, he
says, but if he or she isn’t bleeding, the physician probably
won’t treat something that’s not causing a direct problem.
There are other challenges to POC coagulation testing in the OR.
For one, the devices primarily use fresh whole blood from a fingerstick,
venous sample, or heparinized arterial line. “So the preanalytical
variables and the integrity of the sample are very important,”
Dr. Santrach says. “If you don’t do that right, you
can end up with the wrong answer.”
patients given the same dose of anticoagulant may have different
results. One patient may respond to heparin with a marked prolongation
of the activated clotting time—another patient may have a
different response curve.
of patients are more difficult to manage during the intraoperative
period because they were already on low-molecular-weight heparin
before surgery, or they may have received clot busting therapy in
the emergency room or platelet aggregation inhibitors during cardiac
catheterization in an emergent situation. But the POC coagulation
test identifies the mechanism that needs treatment: protamine sulfate
to reverse too much heparinization, vitamin K for warfarin overdose,
or platelets for the platelet inhibitors.
potential stumbling blocks, POC coagulation testing and treatment
algorithms in the OR are expected to move into the mainstream. “The
advance of technology coupled with new and evolving treatment strategies
will progressively introduce POC testing,” Dr. Jobes predicts.
“Time-dependent procedures will require it, and the cost-revenue
management strategies [hospitals use] will change,” paving
the way for the testing.
may also expand from the OR into the post-recovery period. Newsome
reports that his medical center is “having conversations”
about using more POC coagulation testing after cardiac surgery,
at least during the first 12 hours of recovery.
Point-of-care INR testing in physicians’ offices and clinics
is less dramatic than in the operating theater. Yet use of the method
to manage chronic warfarin patients appears to improve clinical
outcomes and reduce the cost of treating serious adverse events.
It also generates revenue that adds up in a high-volume setting.
At OSU, which
started point-of-service INR management in January, clinic staff
asks patients a few standardized questions and obtains a fingerstick
blood sample that it puts in the CoaguChek machine (Roche Diagnostics).
Within about 90 seconds, the device produces a reading, which it
feeds directly into the computerized system via a cable.
software support program—called CoagClinic—then calculates
the warfarin dosage using a computerized algorithm,” says
Mark Wurster, MD, a hematologist and internist and director of anticoagulation
at Ohio State University. Dr. Wurster is also co-founder and medical
director of Standing Stone, a disease state management company that
holds the patent on CoagClinic.
If the patient’s
INR is too high or low, a message pops up on the computer screen
telling the practitioner what the American College of Physicians
says to do.
length of time for the visit is 12 to 15 minutes, and the clinic
is able to bill separately for the laboratory test and the face-to-face
encounter. By contrast, Medicare will not pay for telephone management
of patients’ Coumadin therapy. The uncompensated service adds
up for doctors’ offices and clinics: “The American Medical
Association estimates that it costs about $7.50 every time someone
picks up the phone, which includes overhead,” Dr. Wurster
Using the fingerstick
POC test and face-to-face encounter, the clinic or physician’s
office bills Medicare $5.42 or thereabouts for the test, which is
essentially a break-even proposition. Medicare pays about $13 for
a CPT 99211, the minimum evaluation and management code for incident-to-service
provided by a nurse or pharmacist, Dr. Wurster says. “That
may be different for private insurers, and Medicaid may pay a little
less, but that’s the ballpark figure,” he adds.
If the hospital
provides the services in the outpatient setting, it can bill under
the outpatient prospective payment system using an APC code. “The
APC for the service pays about four times the incident-to-billing
and INR testing,” Dr. Wurster says.
produced by the point-of-care testing approach isn’t huge
on a per patient basis. But Dr. Wurster notes that his former medical
group at St. Luke’s Hospital, Kansas City, did 12,000 such
visits a year, which would contribute a bit to the bottom line.
encounter also gives nurses and other health care professionals
an opportunity to assess and teach patients. For example, when patients
visit the OSU anticoagulation clinic, medical staff queries them
about symptoms they might be having and determines if they are taking
new medications or have changed their diet.
also essential to look at herbal formulations a patient may be taking,
as these can interfere with clotting,” Dr. Wurster says. “For
example, green tea is loaded with vitamin K and can reverse a person’s
INR very quickly.” The clinic staff also knows to warn certain
patient groups against overindulging in vitamin-K-rich collard greens
at harvest time.
The beauty of
the point-of-service testing method, in Dr. Wurster’s view,
is that you catch an abnormal INR before the patient leaves the
health care setting. “The software program gives you guidelines
to consider holding one to three doses and calculates a dose reduction
using a computerized algorithm,” he says. “It will also
try to get to the new dose using the same pill size, which prevents
patients from getting confused.”
bruises vs. inpatient hospitalization
To assess the impact of the POC approach, Dr. Wurster compared outcomes
at his former practice at the multispecialty continuity clinic at
St. Luke’s Hospital, which used POC INR testing, with the
traditional approach at OSU, which was in place before January.
In comparing the two groups of patients, Dr. Wurster examined three
(defined for the purpose of the study as the number of visits with
INR results in the therapeutic range/total visits). The compliance
rate was about 55 percent on average in the St. Luke’s test
group using POC INR testing. That compared to 38 percent using the
traditional approach at OSU (centralized lab testing and telephone
management of anticoagulant dosing).
Treatment-related complications (defined as hospitalization and emergency room/outpatient
encounters for a diagnosis related to anticoagulation when the INR was outside
the therapeutic range). The experimental group had four complications during
the study period from 2002 to 2003, all of them bruises on the lower extremities
evaluated on an outpatient basis. The OSU patients had 13 inpatient admissions.
Costs. The experimental group’s complication treatment costs added up
to $250, compared with $335,000 for the 13 inpatient admissions at OSU. For
the test group, this represented a relative risk reduction of 89 percent.
In a followup
national benchmarking study involving 30 outpatient settings (seven
primary care, 16 subspecialty, and seven hospital-based clinics)
using POC anticoagulation therapy and the CoagClinic software in
2002, Dr. Wurster and his cohorts found the average INR compliance
rate to be 52 percent. That compared with the 38 percent compliance
rate at OSU using the traditional telephone management approach.
study also looked at two other recognized studies involving POC
testing in subspecialty practices—one with an INR compliance
rate in the 30 percent range and another with an INR compliance
rate of 45 percent. “The [latter two] studies were actually
looking at a subspecialty approach to anticoagulation and were considered
to represent a ‘gold standard’ approach,” Dr.
benchmark study found no statistically significant differences between
INR compliance rates achieved in primary care sites and hospital-based
clinics and subspecialty groups using the new method. In his view,
that means the technology can be used in primary care offices just
as well as in cardiology and other subspecialty settings.
presented the results of the benchmarking study at the Anticoagulation
Forum in San Francisco in May. The study will also be published
in an upcoming issue of the Journal of Thrombosis and Thrombolysis.
With the results
of the benchmarking study now in, Dr. Wurster says researchers can
hone in on questions about the gold standard for treatment based
on the INR compliance rate.
POC INR testing
isn’t all roses. As OSU’s Dr. Wu points out, the testing
is cost-effective in the clinic setting in terms of managing patients
but not in terms of the cost per test. Labs can, in fact, do the
testing more cost-effectively because of the higher volume. “But
in terms of patient outcomes, patient satisfaction and management,
the POC coagulation testing is likely to be cost-effective,”
Dr. Wu agrees. “To run the tests in the lab takes between
40 to 70 minutes overall.”
is that the POC devices use whole blood while the lab uses plasma
to determine the INR. “But if the POC instrument vendor uses
appropriate calibration/ validation to account for that, then accuracy
is less of a concern,” Dr. Wu adds.
Even so, when
the INR climbs too high, POC testing may not be as accurate. In
that regard, “the POC instrument is good for a screening test,
as most patients will have INR within the therapeutic range,”
Dr. Wu says. But when patients have a Coumadin overdose, and the
INR is very high on the POC instrument, the reading may not be accurate.
For that reason,
the OSU coagulation clinic asks the hospital laboratory to repeat
POC tests that produce an INR of 4.5 or higher. The patient waits
at the clinic for the backup lab result. “Every time we have
done that,” Dr. Wurster says, “the backup INR comes
up in a range close enough that treatment recommendations are not
perception of the convenience of point-of-care testing may also
affect its success in some settings. Dr. Santrach reports that Mayo
Clinic’s experience in primary care shows that only about
half of patients choose the point-of-service approach.
people don’t necessarily have time for face-to-face encounters
and prefer to just get their blood drawn and deal with it by telephone
later,” she says. “It depends on how quickly the patients
can get their blood drawn [by the lab] versus coming in for a visit
to see the physician or nurse.”
Karen Lusky is a writer in Brentwood, Tenn.