For most labs, significantly reducing cost, volume, and workload for a given test is an arduous, multilayered undertaking that requires extensive preparation and planning. But for the lab at John T. Mather Memorial, a 248-bed community hospital in Jefferson, NY, cutting its testing volume and time to results by nearly two-thirds for the common nosocomial infection Clostridium difficile (C. difficile) was as simple as swapping out one test for another.

Previously, the lab used a moderate-complexity enzyme-linked immunosorbent assay (ELISA) that tested for toxins A/B, which, if detected, can confirm the presence of toxigenic strains of C. difficile. To rule out infection, the lab tested patients 3 days in a row looking for three negative results. Not surprisingly, the test was time-consuming for both the lab and for hospital nurses who were charged with collecting samples from patients over the 3-day period.

“It was a lot of involvement from the nurses,” says Director for Lab Services Denise Uettwiller-Geiger, PhD, DLM(ASCP), who is responsible for the lab’s menu expansion and technology procurement. “Basically, to be waiting for a stool sample and submitting to the lab 3 days in a row is quite a commitment.” The ELISA was also a batch test, which did not allow the lab to provide testing 24/7.

The lab, however, bore the brunt of the burden, as each batched run took techs about 2 hours to complete. And while systems to automate the microtiter plate do exist, Geiger maintains that they would not end up saving much time considering the relatively low volume of tests her lab performed. “The steps are all the same,” she says, comparing the manual process to the automated one. “And that includes incubation and a manual washing step.”

From the hospital’s standpoint, the big issue was that while samples were being collected and tested, patients had to be virtually quarantined from the general hospital population until C. difficile could be definitively ruled out. “These patients had to be put into isolation,” Geiger says. “So, either they were occupying a single room or two people were cohorted in isolation together.”

For John T. Mather, improving patient bed flow was a top priority. Since most patients need testing only to confirm that they do not have C. difficile (and thus are able to rejoin the general hospital population), implementing a test that could test patients faster was akin to both saving money and improving efficiency for the hospital’s isolation unit.

Two-in-One Testing

C. DIFF Quik Chek Complete™

It was clear the lab was on the hunt for an upgrade when it came across the C. DIFF Quik Chek Complete™ from Inverness Medical, Waltham, Mass, manufactured by TechLab Inc, Blacksburg, Va. The Quik Chek test uses antibodies to identify toxins A/B in a single device, and also for glutamate dehydrogenase (GDH), which tests for the presence of the opportunistic anaerobic C. difficile bacterium. Testing for GDH allows the lab to rule out C. difficile in the amount of time it takes to collect and process a single sample.

To perform the new test, techs add the sample to a tube containing a mixture of included diluent and conjugate. The diluted sample-conjugate mixture is then added to the sample well and left to incubate for 15 minutes. Afterward, techs wash the reaction window with a wash buffer before adding substrate. After a 10-minute incubation period, techs can visually read and report results.

Like the lab’s former ELISA, the Quik Chek test is a moderate-complexity test, and its simplicity made its introduction into the lab relatively effortless. “We did the normal competency education training with staff,” Geiger says. “We introduced them to the test, we showed them the steps … and trained them how to read it with the internal control.” Techs were also certified for competency on performing the test.

With increased sensitivity/specificity, the new test’s negative predictive value can rule out about 90% of the hospital’s patients for C. difficile. “When you detect GDH, you certainly know the test is very specific,” Geiger says. “And for C. diff, in our validation against PCR, we had a 100% concordance for sensitivity.”

Cutting Costs, Saving Time

Geiger estimates her lab now saves more than 1 hour per sample, a 60% overall reduction compared with the previous ELISA test. “Today, a single fecal specimen from a patient is submitted for C. diff testing, and the results are provided to the clinician in less than 40 minutes,” she explains.

Volume has also fallen 60% as testing patients in triplicate has been obsoleted with the new testing algorithm. The time savings the lab now enjoys frees techs up for other tasks, and since the test requires only a single stool sample, nurses share in the improved efficiencies as well.

Perhaps the biggest success, however, was made evident through data compiled by the hospital’s infection preventionists, which revealed significant patient outcome improvements since implementation. By comparing infection rates per 1,000 patient days from 2008 to 2010, the infection preventionists—who consider January to April the high season for C. difficile infections—found a 63% decrease in infection rates during this time period.

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“Our infection preventionists attribute this reduction in C. difficile infections directly to the implementation of the Quik Chek Complete with increased sensitivity of GDH with toxins for a 100% negative predicative value,” Geiger says. “They feel that it’s completely due to rapid turnaround time and improved testing performance.”

The lab also experienced a measurable cost reduction by changing to the Quik Chek Complete. “By not batching anymore, we actually saved 26% and have been able to offer the test on demand,” Geiger says. But she admits the calculation isn’t inclusive of all savings attributable to the switch. “I don’t think I even accounted for how much less testing we’re doing.”

Overall, the lab has embraced its new efficiencies. “We’re getting faster results in a shorter amount of time,” Geiger says. “If you talk to our infection preventionists, they’re very pleased and feel the laboratory has made a large contribution in putting these patients at the appropriate level of care.”

Stephen Noonoo is associate editor of CLP.