Demand rises for point-of-care tests

The long-established blood-glucose and home pregnancy
tests, it appears, were merely forerunners for the technological tsunami
that is sweeping through hospitals, clinics, and physician offices. With
doctors and patients not wanting to wait hours or days for test results
to come back from the lab, the demand for rapid diagnostic, or
point-of-care tests (POCT) is rising.

Rebecca Taalbi, CLS, ASCP, point-of-care coordinator
at Wheaton Franciscan Healthcare-St. Francis in Milwaukee, WI, says her
hospital regularly uses 11 or 12 different POC tests — for which the
hospital’s lab is ultimately responsible. One of the benefits of these
tests, she says, is the rapidity in which the nurses who are
administering them — and, therefore, the physicians — can get accurate
results.

Tests, for example, that require a finger stick yield
results in about 30 seconds. A urine dipstick takes 60 seconds. Gastric
and fecal tests to determine the presence of occult blood take one
minute. And while measuring creatinine levels takes about two minutes,
ACT tests can vary, depending on clotting times. Even the test for
premature rupture of membrane, or PROM, which looks for leaking amniotic
fluid in pregnant patients, will yield results in 10 minutes or less.

But Taalbi also is quick to note: “Apples are not
equal to apples when it comes to point-of-care testing.” Finger-stick
glucose tests are a prime example, she says, because these tests can
yield a slightly different result each time the patient is tested. As a
result, physicians still rely on those results coming from the
lab. “They want to know,” Taalbi says, “which is point-of-care and which
is lab [results].”

Still, Taalbi says point-of-care testing has proven
to be easier and with faster turnaround times. “There’s a trade-off, but
in general it is a good thing.”

Meeting the demand

The growing use of POCT is undeniable, and the field
is expected to continue to expand as more tests are developed and more
clinicians adopt them in their day-to-day diagnostics. “There has been a
huge shift from being considered toys to becoming critical systems,”
says Rob Morse, marketing manager for Chelmsford, MA-based ESA
Biosciences. Morse admits that there is a finite number of tests that
can be used at point-of-care. Yet, he says what is driving the adoption
of these tests is the desire to get the same results that can be gotten
from a reference lab but in far less time. There is, however, a
challenge, he says. “You have to put enough sophistication into the test
to make it easy for caregivers to use.”

Patricia Ristuccia, MS, MT(ASCP), director of
Laboratory Services at Doctors Hospital of Sarasota in Florida, says,
“We have been performing point-of-care testing here at Doctors Hospital
for more than 10 years, starting slowly with only bedside glucose tests
being performed. The laboratory oversees the POCT program with the
testing being performed by licensed, trained personnel in various areas
throughout the hospital. The laboratory is responsible for the original
training of all new personnel with subsequent recertifications being
performed by charge nurses/nurse supervisors. The laboratory is also
responsible for any maintenance or returns on any equipment needing
repair.”

Another reason for a greater acceptance of POCT is
the alarming rates of antibiotic resistance, says Alyce Ancier, product
manager for Genzyme Diagnostics, in San Diego. By eliminating the
possibility of a bacterial infection early on, or by determining the
exact cause of the infection, the physician can then administer the most
appropriate drug, she says. This also allows the physician to quickly
eliminate certain diseases so that other diagnostic tests can then be
ordered, she adds. Since this is all being done in a doctor’s office, a
clinic, or at the patient’s bedside, the point-of-care environment
becomes one of “test and treat,” Ancier says.

At the Doctors Hospital, Ristuccia says, “The main
area where POC orders need differentiating would be the emergency
department (ED). Our initial POC cardiac markers are performed by
nursing on instrumentation located in the ED. The point-of-care tests
performed at Doctors Hospital ED include bedside glucose, urine
pregnancy, and occult blood. We will begin testing creatinine in
radiology in the near future to help expedite our TAT for CT patients.

“Physicians obtain the instrument print-out from the
nurses performing the testing as the tests are finalized. The instrument
actually queries our LIS to order/result the test in the computer. The
ED physician gets real-time resulting of those markers. Our ED POC
instruments and our laboratory instrumentation are compatible, so if
there happens to be a backlog of testing in the ED, the nurses can bring
samples to the lab. Thus, we can perform the testing without a change in
methodology/normal ranges,” says Ristuccia.

Product development

Barry Plant, senior product manager at Bio-Rad
Laboratories in Hercules, CA, agrees with Morse, adding that the quality
of POC devices has evolved to the point where POC tests are now
producing lab-quality results.

To meet the growing demand, medical-device companies
continue to develop new test kits or to refine those already on the
market. Most have recently launched new products or have new tests under
development.

Bio-Rad, for example, has developed a testing device
to measure A1C values in diabetic patients. “Since glucose binds to
hemoglobin in red blood cells, an A1C value gives an indication of
glucose control and is used by physicians to develop a treatment,” Plant
says. The company markets a fully automated A1C analyzer that is small,
runs on batteries, and is portable. In fact, it has been taken out to
farms in central California to test migrant farm workers, he says.

For lead testing, Rob Morse says most reference labs
rely on mass spectrometry or atomic-absorption tests. ESA Biosciences
markets a blood-lead testing kit for use in pediatric practices, mobile
health-services vans, and community health centers. The test requires
only 50 microliters of blood taken from a single finger stick, Morse
says, and it takes only three minutes to get the results, he notes.

Building on product success

Douglas Bryant, president and CEO of San Diego,
CA-based Quidel Corp., says most of his company’s POC assays run 10
minutes or less and that physicians will continue to adopt these tests
as long as the specificity of these tests meets their needs. Quidel
Corp. offers a full-range of point-of-care tests and will be launching a
new fecal occult blood test during the fourth quarter of this year,
followed by a mononucleosis test in the first quarter of 2010. At the
end of 2003, the company launched its QuickVue Infuenza A+B test. It
features a three-step procedure using either a nasal swab, wash, or
aspirate, and yields results in 10 minutes. In 2006, the company
launched its QuickVue RSV test, which uses a dipstick immunoassay to
quickly and qualitatively detect the respiratory syncytial virus (RSV)
antigen (viral fusion protein) directly from a nasopharyngeal swab or
nasopharyngeal-aspirate specimens from symptomatic pediatric patients.
Bryant says that in 2010 his company will launch a single test that
combines both the Influenza A+B and the RSV tests.

POC testing for bacterial vaginosis

Genzyme Diagnostics also offers a full range of
point-of-care tests including those for influenza A and B,
mononucleosis, H pylori and a CLIA-waived test for trichomoniasis,
says Alyce Ancier. It also has a CLIA-waved test that detects bacterial
vaginosis caused by gardenerella, bacteroides, Prevotella, or mobilincus.
The test detects elevated vaginal fluid sialidase, an enzyme produced by
the bacterial pathogens associated specifically with bacterial vaginosis.
Ancier explains the simplicity of the test by saying that a vaginal swab
is put into a test vessel containing a potassium acetate buffer solution
and a chromogenic substrate of bacterial sialidase, and is left to stand
for 10 minutes. Then, one drop of a developer solution containing sodium
hydroxide is added and the mixture is gently swirled. If it turns blue
or green, the test is positive; if it turns yellow, it is negative.

POCT on the go

Doug Guarino, director of corporate relations at
Waltham, MA-based Inverness Medical Innovations, says point-of-care
testing reflects a general societal trend where “everybody wants answers
quickly.” Because so much patient data is already captured at the
point-of-care, it is only natural that testing should also move closer
to the patient and the event. Diversification put Inverness on the map
as a provider of POCT, including those for pregnancy, drug use, sexually
transmitted diseases, HIV, rubella, and influenza, says Guarino. The
company is prepared to launch a new point-of-care HIV test which will
make its debut in Africa.

One Inverness analyzer is a portable,
battery-operated device that can be used in clinics, hospitals, and
doctors’ offices, can yield results in 15 to 30 minutes, and is the
first of its kind to test for CD4 cell enumeration. The successful
completion of clinical trials in 2008 made it possible to plan a launch
of this new test by the end of 2009. By using a small finger-stick blood
sample, the analyzer may also be able to deliver not only CD4 cell
enumeration but, ultimately, provide diagnostic capabilities for a wide
array of additional markers, Guarino, says. This new device will
complement the company’s existing arsenal of HIV tests including its
Clearview HIV 1/2 STAT-PAK, a qualitative screening test for the
detection of HIV-1 and HIV-2 antibodies in whole blood, serum, or plasma
samples. CLIA-waived for whole blood samples collected by finger stick
or venipuncture, this test features a simple two-step process leading to
reactive results in as little as 15 minutes.

POCT here to stay

If these tests and devices are any indication of the
direction in which diagnostic testing is headed, it appears that testing
is further shifting to the point-of-care. Can the results be expected to
be as good as those coming from the lab? Have those who are
administering these POC tests been trained well enough not only to
administer them but also to read and interpret the results as well?

Bio-Rad’s Plant says hospital and reference labs have
voiced concerns over quality-control issues, but explains he has
observed that controls are definitely in place and that “operators are
well-trained” in the tests they administer.

As for Taalbi, whose hospital began using
point-of-care tests at the beginning of this new century, says her
Number One goal as a point-of-care coordinator is “to support nursing
capacity to provide error-free, accurate lab testing.”

Richard R. Rogoski is a freelance journalist based in
Durham, NC. Contact him at
[email protected].