Yet the rationale for POC testing is not likely
to change, and that is to improve patient outcomes in ways that more cost-effective
traditional laboratory testing cannot. Hospitals that do the best job of reaping
the benefits of POC testing keep that goal in mind in executing and monitoring
faster near-patient testing to ensure that it’s not just, well, faster—or
worse, inaccurate.
Paula Santrach, MD, co-director of point-of-care testing at Mayo Clinic, Rochester,
Minn., says the “advantage of [point-of-care] testing is tied to a process
of patient care—not just having it rapidly and readily available.”
As a case in point, Baystate Medical Center in 2005 added point-of-care creatinine
testing in its cancer center to accommodate the outpatients who need renal
function screening before receiving their scheduled chemotherapy treatments.
Using the central lab to do such testing turns chemotherapy treatment into
an “all-day procedure” for patients, Dr. Nichols says. But clinicians can use
portable chemistry analyzers to obtain creatinine values and calculate patients’ glomerular
function. As a result, patients can receive their chemo treatments much more
quickly and be on their way within a couple of hours.
In another POC testing application with the potential to better meet patient
needs, Baystate’s rapid-response team has requested that POC lactate testing
be added “to evaluate patients who are going downhill,” Dr. Nichols says. “The
lactate is sensitive to poor perfusion, which may be related to unrecognized
sepsis.” This can cause a patient’s condition to deteriorate quickly, and lactate
can help alert the medical team to potential problems before the patient becomes
critical.
Hundreds of hospitals are implementing the latest obstetrical POC test on
the block: the AmniSure Rupture of Membranes Test. Physicians or nurses can
perform the test as part of a triage assessment of pregnant women to more quickly
and easily detect premature rupture of membranes, or PROM.
PROM is “responsible for up to 30 percent of premature deliveries, for a total
cost of $13.6 billion in health care spending,” says Michael Friedman, PhD,
CEO of AmniSure International LLC, Cambridge, Mass.
The test, which requires a vaginal swab, is so far the only FDA-cleared rapid
immunoassay for detecting PROM. The test “uses a cocktail of monoclonal antibodies
to detect in a key-lock fashion a protein marker of amniotic fluid,” Dr. Friedman
explains. “The technology is very different from the multiplicity of methods
used today to detect amniotic fluid leakage,” he adds, noting that according
to the published data, “the AmniSure ROM Test is about 99 percent accurate
in detecting amniotic fluid in the vagina. And it’s the only test that doesn’t
require an invasive speculum exam to do so.”
Nurses or OB/GYN residents at the University of Kansas School of Medicine
at Wesley Hospital perform the AmniSure test on patients in the labor and delivery
area. “We use AmniSure primarily for women at term or 37 weeks or greater gestation,” says
Brooke Grizzell, MD, a third-year OB/GYN resident at the University of Kansas
in Wichita, who conducted a study comparing the AmniSure test to speculum exam
results on 50 patients and found AmniSure to be accurate in every case.
Dr. Grizzell believes the AmniSure test has “improved outcomes by avoiding
false-negatives, for example, saying someone’s membranes are not ruptured when
in fact they are ruptured.”
The University of Kansas hospitalizes a pre-term pregnant woman with ruptured
membranes to monitor her for “any uterine tenderness or fever,” delivering
the baby if there are signs of chorioamnionitis or fetal/ maternal distress,
Dr. Grizzell says. The incidence of chorioamnionitis has not been tracked since
AmniSure was implemented, but “that would be a good study” to do, she says.
Abbott Northwestern Hospital, Minneapolis, has also implemented AmniSure as
a POC test in the maternal assessment center, says Lynn McDonald, BA, CLS (ASCP),
point-of-care testing coordinator. The nurses “love the test,” which she attributes
in part to the unnecessary speculum exam.
In constrast, nurses tend not to relish the Sisyphean POC testing effort required
to achieve tight glycemic control in patients who develop hyperglycemia because
of the stress of surgery or illness. But no one argues about the proven values
of the TGC protocol.
The literature shows tight glycemic control benefits cardiac patients and
the general medical surgical population, including decreasing mortality, says
Ruth Mencl, MN, RN, CDE, diabetes program manager at Saint Luke’s Hospital,
Kansas City, Mo., which has implemented glycemic management protocols in all
of its adult ICUs. Yet the nurse staffing requirements to do the glucose POC
testing are “huge,” says Mencl.
“Not only do you have to stick the person and do the test,” Mencl says, “but
then you have to do something about the result, which sometimes includes changing
the insulin dose or changing the IV fluids…. We know this is state of the art
for cardiac patients but we also have a nursing shortage. So to be safe, we
keep most of our [postoperative cardiac bypass] patients in the cardiovascular
intensive care unit until they are stable enough to have the two-hour blood
sugars, which the nursing staff on the cardiac step-down unit do.”
The frequent fingersticks and testing is also a “big patient dissatisifer,” Mencl
says. That’s especially true for myocardial infarction patients in the coronary
care unit, as they tend to become more uncomfortable with all of the glucose
testing compared with the less-alert post-op cardiac bypass patients in the
cardiovascular ICU. Many of the latter patients also have IV lines from which
nurses obtain specimens for glucose testing.
In Mencl’s view, existing technology could help lessen this dissatisfaction.
Diabetic patients with type 1 can use sensor devices “as an adjunct to their
insulin pumps to evaluate their diabetes control,” she says. “If you could
have a closed-loop device like that to read a patient’s blood sugars and give
an insulin infusion based on the blood sugar, it would eliminate the problem
of patient dissatisfaction with the frequent testing, and you would have immediate
results.”
Abbott Northwestern, which strives for strict glycemic control in its ICUs
and some medical-surgical units, has attempted to ease the protocol’s burden
on nurses by increasing the number of glucose meters in each clinical area,
McDonald says. “And we have been training some of our certified nursing assistants
to do some of the patient testing” in lieu of having nurses do it exclusively,
she adds. The assistants report the glucose results immediately to the nurses.
In some cases, a hospital finds what it believed to be a promising POC testing
approach to be more trouble than it’s worth. For example, Baystate Medical
Center has moved away from POC-driven heparin monitoring during cardiac bypass
surgery, which perfusionists at one point thought they needed to do, Dr. Nichols
says. Baystate had been using a device with a “dosing scheme where you’d plug
in the patient’s parameters and run a baseline activated clotting time and
protamine test,” he says. The device would then “draw a standardization curve,” predicting
activated clotting as the patient underwent cardiac bypass, and how much heparin
the patient needed during the bypass procedure in order to reach and maintain
the target. The curve also predicted how much protamine sulfate the patient
required to reverse heparinization at the end of surgery.
Sounds good, but the perfusionists felt the approach caused them to do too
much “micromanagement,” Dr. Nichols says. “They were changing the heparin dosing
too much and constantly worrying about it instead of just monitoring ACT and
dosing the patient with heparin based on the patient’s weight,” he adds. “Doing
the latter, they found they were giving fewer blood products and the patient
had better outcomes.”
Dr. Nichols notes that several devices can be used for the heparin monitoring
and dosing scheme. “But a number of cardiac surgical centers are finding they
can do just as well with monitoring using ACT testing [as] the heparin monitoring,” though
a number of institutions are “very married” to the latter approach, he says.
In other cases, hospitals sometimes can’t get the majority of their clinicians
engaged with a POC program that has a track record for improving patient outcomes.
Mayo Clinic found that to be the case when it rolled out an evidence-based
POC coagulation-driven transfusion algorithm for patients undergoing cardiac
bypass surgery that a pilot program there had shown reduced by 60 percent the
number of patients with excessive microvascular bleeding who received blood
products. And at least six other studies have shown that the “POC approach
with more targeted transfusion therapy reduces the patient’s risk of transfusion
and for some patients” also the risk of blood loss, says Mayo’s Dr. Santrach.
Yet during the year that Mayo Clinic’s POC testing coagulation program for
bypass surgery was in effect, about half of the anesthesiologists, who are
the ones typically ordering the intraoperative coag testing, participated in
it, says Gregory Nuttall, MD, professor of anesthesiology at Mayo Clinic. (The
program has been suspended while the lab rebuilds the POC-driven transfusion
algorithm to accommodate new POC instruments, including one for PT and APTT
testing.)
Dr. Nuttall explains the anesthesiologists’ lackluster participation in the
POC program, in part, by noting that “physicians are like herding cats,” meaning
people who go into medicine tend to be “independent thinkers.”
The POC program’s implementation did show that anesthesiologists tended to
order the tests intraoperatively with the faster turnaround times to guide
transfusion and treatment decisions for bleeding, Dr. Santrach says. Thus,
she believes the laboratory can address the compliance issue by making the
testing as “readily available and fast as possible” once the POC program resumes.
Dr. Nuttall says they also plan to offer educational activities for the anesthesiologists
about the POC testing once it’s back in action.
Accuracy problems can derail even the simplest testing with dire consequences.
To ensure accuracy of its POC testing, Saint Luke’s looks at a number of quality
issues, including repeated POC glucose tests. David Colard, MT (ASCP), point-of-care
testing coordinator at Saint Luke’s, explains that if the glucose tests repeated
within 15 minutes “don’t compare well, there is some sort of preanalytical
issue where the sample is either contaminated with IV fluid containing glucose,” in
which case the reading is falsely high, “or IV fluid without glucose.” The
latter produces a falsely low glucose reading.
“Fingersticks contaminated with alcohol can [also] give erratic results,” Colard
says.
Then there are “strip-dosing” problems, he adds. “With the strip we use, it’s
possible to underdose the strip and not get enough sample into the strip, so
it gives a result that may be accurate but frequently is not.” The Saint Luke’s
laboratory is evaluating a patient meter, Roche’s Accu-Chek Aviva, which “seems
to have an excellent strip-sensing mechanism. If the strip is not completely
filled with blood within five seconds, the meter aborts the test without giving
a result,” Colard says. Applying this type of strip technology to a meter designed
for institutional use would significantly reduce the potential for erroneous
results, he adds.
As a QA measure, Abbott Northwestern posts on its glucose meters “all of the
issues requiring” nurses to obtain a specimen to send to the lab, McDonald
says. “The nurses can review those when they do the testing.”
At Oklahoma University Medical Center, Oklahoma City, which uses Abbott’s
iStat portable clinical analyzer to perform 98 percent of its POC testing,
including coagulation, chemistry, and blood gasses, the lab focuses on trying
to get nurses to recognize a questionable result, and when to “suspect sample
integrity issues as the cause of a potentially inaccurate result,” says Ivy
Douglas, MT(ASCP), laboratory point-of-care coordinator. iStat’s fail-safe
mechanisms also help prevent false results. The analyzer is designed such that “if
a sample is clotted or there are bubbles in it, it won’t provide an answer
at all,” she says. “Issues such as diluted specimens from IV fluids or hemolyzed
ones should show up in the results, which we teach the nurses to recognize” and
in which case they’re taught to repeat the testing.
Data management plays a key role in ensuring POC programs provide consistently
accurate results and improve care. Mark Wurster, MD, an internist at Ohio State
University Medical Center, Columbus, says there are “great benefits” to performing
POC INR testing for outpatients— “the biggest of which is you get an
INR within 90 seconds…and you can readjust the person’s warfarin right there.
“If you have an INR that’s two to three days old, it’s worthless. By the
time you make a dosage adjustment, it’s probably not going to match what’s
going on with the patient physiologically,” he says.
But “if you just use the POCT and nothing else in terms of how you manage
the patient, then you’re going to commit the same errors that you would in
using a central lab—only you’ll be committing those errors a bit faster,” Dr.
Wurster cautions. For example, without a computer decision system, the clinician
has to calculate the patient’s new warfarin dosage based on the INR reading,
a process fraught with the potential for transcription and mathematical error.
Using OSU’s computerized decision system, which Dr. Wurster designed, health
care staff seeing patients ask them whether they are taking any new medications
or herbal remedies, changed their diet, or have new symptoms such as bleeding.
The staff then enter all of that information into the software program. And
the POC device automatically enters the INR result into the software program.
The software calculates the new INR and adjusts the warfarin dose, if needed.
The system produces a printout for the patient, listing “the new warfarin dose
on a daily basis, any comments for the patient provided by the health care
provider, as well as return visit information,” Dr. Wurster says.
Saint Luke’s Colard says the information technology component of POC testing
is “really important with tight glycemic control,” especially for Saint Luke’s
virtual ICU where intensivist physicians and nurses monitor ICU patients from
a central monitoring site. “There’s a critical need to make sure we have the
glucose values entered accurately into the patient’s electronic medical record.” He
expects to see multiple new meters on the market this year that will provide
wireless communication capability. And “we hope to see wireless technology
that would enable real-time reporting to the EMR, as well as data-management
systems that will have some logic built in where you can set up rules to reduce
the number of results held for human review” before they go into the patient’s
EMR, Colard says.
Point-of-care cancer screening tests are already in play overseas, including
ones for prostate-specific antigen, carcinoembryonic antigen, and alpha-fetoprotein
(the latter tests for liver cancer), says Baystate’s Dr. Nichols. The tests
are “almost like a pregnancy test” where a dipstick develops a line or changes
color if the test is positive, he says. In the U.S., he says, the FDA has approved
a CLIA-waived POC test for bladder cancer.
With some of the soon-to-be-available devices involving molecular testing,
Dr. Nichols foresees potentially being able to “type hospital nosocomial infections
where a device shows a color change or reads a positive hybridization and you
know it’s MRSA or influenza or another bug, for example.” In the past five
to seven years, PCR has revolutionized sexually transmitted disease testing. “With
POCT, you could deliver results in the clinic and eliminate the followup confirmatory
testing step,” which could have a “powerful effect on outcome and is being
worked on,” Dr. Nichols says.
While some laboratory professionals years ago viewed POC testing as a threat,
Dr. Nichols says, “most clinical pathologists have dealt with POCT long enough
to know that the testing simply changes the face of the lab—it doesn’t replace
it.” For one, POC testing gets laboratorians out of the laboratory and consulting
with nurses and physicians. “The lab has to ensure the testing is done correctly,
which requires oversight. So there are roles for the laboratory in the POCT
process,” he says.
In her decade of experience as a point-of-care coordinator, Abbott Northwestern’s
McDonald has found that the lab has to “be very supportive of the [POCT] program
and take ownership of it if it’s going to succeed. And the lab has to have
a good relationship with nursing and nursing administration—it’s a joint venture.”
Clara Sumeghy, MS, CT (NRCC), alternative site testing coordinator at Henry
Ford Hospital, Detroit, agrees, and sees POC testing as a “rapidly developing
technology that has become a big business in health care.” But “we realize
that the nursing staff are not trained laboratorians and are very busy taking
care of critically ill patients.” She thus envisions a growing number of POC
testing coordinators to make it possible for the laboratory to monitor testing
and competency.
Ultimately, the growth in POC testing may mean more testing in the central
laboratory. For example, Baystate has a “huge POCT glucose program…so you’d
predict perhaps that we’d do fewer glucoses in the main lab,” Dr. Nichols says.
But “our glucose volume has been rising steadily due to the intensive insulin
therapies,” he says. The laboratory has to verify blood sugars. And clinicians
are diagnosing more patients with glucose problems. “We are still using the
main lab to diagnose diabetes and insulin resistance. The core lab is also
used for routine physicals involving glucose testing.”
Thus, confirmatory testing or testing to follow up on the POC result, as well
as ancillary tests ordered on the basis of the POC result such as hemoglobin
A1c, fall to the laboratory. In this way, Dr. Nichols says, POC testing can
be a “facilitator” for additional testing performed in the laboratory.
