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93 Executive Briefing The Clinical, Financial & Emotional Benefits of Molecular C. Difficile Testing A single Clostridium difficile infection presents an array of challenges for hospitals. A December 2015 study in the American Journal of Infection Control found C. difficile infections can increase hospital costs by 40 percent per case, averaging $7,285 in additional costs. What's more, study authors report hospitalizations due to C. difficile increased by more than 200 percent from 2000 to 2009. The study also outlines clinical consequences of C. difficile, in- cluding an 8.4 percent higher chance of readmission within 30 days, a 55 percent longer hospital stay and a 2.2 percent greater risk of mortality than patients without the infection. These findings show that efficient detection and proper diagnosis of a C. difficile infection is critical to patients' safety and hospitals' financial stability. Hospital laboratories are increasingly turning to molecular testing to achieve best diagnoses and outcomes. Ensuring Appropriate Sample Testing Accurate diagnosis of C. difficile begins with appropriate sam- ple testing. Sending inappropriate samples to the lab can drain resources — time, capital and otherwise — and also result in mis- diagnoses. For example, while unformed stools are certainly an indicator of a potential infection, that symptom alone isn't enough to warrant testing a stool sample for C. difficile; loose stools can be caused by any number of reasons. When assessing a patient for a possible C. difficile infection, evaluating patient history is critically important, says Rodney Arcenas, PhD, clinical scientist of microbiology and molecular testing at Memorial Regional Hospital in Hollywood, Fla. "Many of the symptoms of diarrheal disease overlap," Dr. Arcenas says. "That's where the patient history comes into play with knowing how likely it is that C. difficile is the cause of a patient's diarrhea." Lance Peterson, MD, director of microbiology and infectious diseases research at Chicago-based NorthShore University HealthSystem and the University of Chicago, agrees. He says more patients have diarrhea than have a C. difficile infection. "About 20 percent of patients coming into the hospital will have loose stools, and it might be from the medication they are on; it might be from the food they're eating. Most of them do not have a C. difficile infection," Dr. Peterson says. "In the hospital setting, maybe five or 10 patients out of 1,000 will actually have a C. dif- ficile infection, whereas 20 percent will have some loose stool." Typically, a patient producing at least three loose stools in one day is a first indicator of an appropriate sample, but it is a clini- cian's due diligence to rule out other factors that could contrib- ute to the diarrhea. Like Dr. Peterson said, the patient may be on laxatives for health-related reasons or other medications that cause loose stool. Indicators that a patient's loose stool should be sent to the lab for C. difficile testing include recent antibiotic treatment and if the patient is coming from a nursing home or long-term care facility, Dr. Arcenas says. Types of Tests After determining a sample is appropriate for testing, there are multiple ways hospital labs can test the sample for C. difficile. Chris Newhouse, PhD, marketing manager of microbiology at Roche Diagnostics, says the C. difficile testing market is largely split 50/50. Half of labs use the more traditional algorithm of an enzyme immunoassay that detects the toxins responsible for an infection. The other half has adopted polymerase chain reaction testing, or molecular testing, like Roche's cobas® Cdiff Test that is performed on the cobas 4800 system. PCR testing copies small segments of DNA and tests those for the presence of an infection. The sensitivity levels — how often a test produces a positive C. difficile result — of these two types of tests is often the subject of debate, as some microbiologists suggest molecular testing is ac- tually too sensitive. According to Roche product labeling, the sen- sitivity of its Cdiff molecular test is 96.7 percent. A technical brief from Cleveland Clinic Laboratories indicates the sensitivity of an enzyme immunoassay is between 61 and 94 percent. That means Efficient detection and proper diagnosis of a C. difficile infection is critical to patients' safety and hospitals' financial stability. Hospital laboratories are increasingly turning to molecular testing to achieve best diagnoses and outcomes. Sponsored by: