Order more tests? With diabetes, answer may be ‘yes’

Jan Bowers

March 2013—In patients with diabetes mellitus, hemoglobin A1c testing frequency is largely in line with recommended guidelines. In those same patients, LDL testing is not performed frequently enough, and urine protein testing frequency falls far short of recommendations.

Those are the results of a recently completed Q-Probes study of whether and how laboratories monitor the frequency of diabetes testing, and how closely the frequencies in their institutions hew to the American Diabetes Association recommended guide­lines.

“It’s important to focus on both over- and underutilization, because sometimes in the lab we tend to focus only on whether we’re performing tests that may not be necessary,” says Peter L. Perrotta, MD, medical director of clinical laboratories at West Virginia University Hospital, professor of pathology at West Virginia University School of Medicine, and a coauthor of the CAP study. But there’s another side, he says: “Tests that should be ordered are not, or they’re not ordered frequently enough.”

In the aggregate, the study found that 95 percent of patients had eight or fewer HbA1c tests in the prior 24 months. (The ADA recommends HbA1c testing at least twice yearly but no more often than every three months.) Among patients who had had at least three HbA1c tests, 79 percent had at least two LDL tests and 27 percent had at least two urine protein tests in the prior 24 months. ADA guidelines recommend at least annual monitoring of LDL and urine protein, with no recommended maximum number of tests.

“It’s just a little disappointing that among these patients who had at least three HbA1c tests within 24 months, 21 percent didn’t get their LDL tests and 73 percent didn’t get their urine tests” at the recommended frequencies, says coauthor Teresa P. Darcy, MD, MMM, medical director of clinical laboratories, University of Wisconsin Hospital and Clinics, and associate professor of pathology and laboratory medicine, University of Wisconsin School of Medicine and Public Health. Coauthor Peter J. Howanitz, MD, says the protein­uria findings were, to him, “the most shocking.”

“I think the take-home message is that we have to be more aggressive in monitoring urinalysis. We’re not doing what we’re supposed to do; we need to do it once a year. And we have to make sure we continue to monitor hemoglobin A1c values.

“It was relatively good, but there’s room for even further improvement,” adds Dr. Howanitz, director of clinical laboratories at State University Hospital and vice chair and professor of pathology at State University of New York Health Science Center.

The Q-Probes, “Frequency Monitoring of Outpatient Laboratory Testing,” investigated the frequency of HbA1c, low-density lipoprotein, and urine protein testing. Forty-nine participating labs submitted 1,915 cases that met the criterion of at least three HbA1c tests in the prior 24 months (a level designed to exclude patients being screened for diabetes). Participants also reported the number of LDL and spot or random urine protein tests performed over the same 24 months. For all three tests, the dates and results of the three most current tests were recorded. Inpatients and outpatients were included. Point-of-care and pediatric specimens and patients with known hemoglobinopathies or kidney transplants were excluded.

Dr. Perrotta urges caution in interpreting the data, especially the results related to proteinuria. “Some people may be using point-of-care testing, or they might be using urine dipsticks—which they really shouldn’t do—for screening diabetics,” he points out. Dr. Darcy also notes that some patients may have been monitored using 24-hour timed urine samples, which the study would have missed. Even so, says Dr. Perrotta, “that number was a little lower than we expected. The LDL frequency also seems low, which is surprising given the large number of LDL tests that are done on everyone.”

“That one is a little harder to explain,” he adds.

The study also explored the laboratories’ practices with respect to monitoring test use, communicating guidelines for test frequency, and detecting duplicate test orders. When asked how the participating lab monitors whether tests are ordered at appropriate frequencies, more than 72 percent said test frequency is not actively monitored. About 21 percent said they monitor frequency through the laboratory information system or other computerized system.

Where clear test utilization guidelines exist, is it the laboratory’s responsibility to communicate those guidelines to clinicians and ensure they’re followed? The coauthors say the lab has a key role but can’t do all the heavy lifting. Says Dr. Darcy, “I think the study points out opportunities for the laboratory, because we have so much data, to be an active participant in setting policies to help monitor that the guidelines are being followed.” On the other hand, Dr. Perrotta says, putting the onus on the laboratory is “difficult when physicians are responsible for providing information that shows the medical necessity of testing.” Even getting a handle on utilization is a big challenge for most labs, says Dr. Howanitz, pointing to the nearly three-quarters of participating labs that said they don’t monitor test frequency. But he called it “absolutely” important that they do, “because we can’t waste effort, time, or money on doing things that are not indicated.” He adds, “If our health care system is going to become much more effective, we’re going to have to develop ways to do these kinds of things.”