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  Reality check for POC testing—making it work

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January 2007
PAP/NGC Programs Review

Karen Lusky

Point-of-care testing has come a long way from a handful of simple waived tests to what is today a multibillion dollar global market that holds great promise for the future. “Certainly there’s the potential, if not in five years then in 10, for molecular technology to enter the POCT realm, which will revolutionize testing and care,” says James Nichols, PhD, director of clinical chemistry at Baystate Medical Center, Springfield, Mass.

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.


Karen Lusky is a writer in Brentwood, Tenn.