IDWeek Tackles Improved Ordering Strategies

IDWeek, the combined annual meeting of the Infectious Diseases Society of America, the Society for Healthcare Epidemiology of America, the HIV Medicine Association, and the Pediatric Infectious Diseases Society, was held Oct. 4 to 8 in San Diego.

DTET examined abstracts presented and identified a common theme of trying to improve appropriateness of infectious disease test ordering. Below is a sampling of presented abstracts that highlight the need to improve reflex testing, electronic-based methods to increase the appropriateness of test ordering, as well as an examination of renewed interest in alternative, nonblood based specimens for rapid testing.

Low Frequency of Reflex Flu Testing Seen
Despite, national guidelines, provider compliance with recommendations for reflex polymerase chain reaction (PCR) testing for negative rapid flu results are low.

Intermountain Healthcare (IH) operates a nonprofit system of 22 hospitals, 41 urgent care centers, and more than 185 physician clinics serving the Intermountain West. The researchers identified orders for rapid flu tests (BD Veritor) during a high-activity period in the 2016-2017 flu season (December 2016 to March 2017). Tests were ordered at any one of the IH locations. The proportion of reflex tests ordered within 48 hours of rapid flu testing was calculated.

The researchers, led by E. Kent Korgenski, from University of Utah School of Medicine in Salt Lake City, identified 9,623 patients assessed during the study period and determined the overall reflex to PCR within 48 hours occurred in 9.6 percent of patients. Reflex testing frequency was much higher in the hospital setting, particularly in the emergency department (20.5 percent) and among inpatients (30.4 percent), compared to ambulatory care settings (2.0 percent) and urgent care clinics (0.6 percent).

The Impact of ‘Hard Stops’ for C. Diff Test Ordering
An abstract presented at IDWeek 2017 assessed the impacts of implementing “hard stops” in electronic medical records (EMR) as a means of improving appropriateness of C. difficile (C. diff) test ordering. The study found that EMR alerts reduced inappropriate testing, without negatively impacting patient outcomes.

In the Johns Hopkins University School of Medicine study, EMR alerts were triggered for C. diff tests ordered in a patient with previous test (14 or 7 days for positive or negative) or receipt of laxative within the last 48 hours. The initiative began at an academic hospital in October 2016 and at two community hospitals in December 2016 and January 2017.

The researchers found that mean weekly C. diff testing rates declined significantly before and after the intervention (146 pre-intervention versus 119 post-intervention). The average number of weekly EMR alerts was 51 (26 for laxatives, 14 for previous negative test, three for previous positive test, and eight for undetermined reasons).

Among the 83 patients who had an EMR alert, but for whom the clinician did not pursue testing, outcome review showed that for 36 diarrhea resolved, for 21 an alternate cause found, 11 had subsequent C. diff testing later in the admission (6 negative, 5 positive results), 12 patients were discharged home, and three died from non C. diff infection-related etiology.

Test Names Can Optimize Ordering Patterns
Despite guidelines to the contrary, the emergency department at University of Wisconsin-Madison had a high number of Group A Streptococcus (GAS) reflex culture orders were being placed for adults with negative results from rapid antigen detection testing (RADT).

In November 2016 the institution changed its ordering language. To differentiate the ordering pathways for children and adults, with the goal of increasing guideline compliance, the word “peds” was added for RADT with reflex culture orders, while the word “adult” was added for RADT without reflex culture. The number of GAS reflex culture orders for adult patients in the emergency department was tracked for six-months following the change and compared to data from the year before.

The researchers found that pre-intervention, the average number of adult GAS reflex cultures per month was 66, which fell to 34 following the change in ordering language. The percentage of total RADT tests that underwent reflex culture changed from 99.5 percent to 49.0 percent before and after the intervention, while the number of RADT tests with no reflex culture ordered showed a proportional increase. The number of add-on culture orders was also tracked, but there was no marked increase in these orders during the intervention period.

Oral Fluid For Syphilis Testing
A group of University of California Los Angeles researchers tested whether saliva could be used to replace whole blood as the specimen of choice for rapid syphilis testing (qualitative immunoassay).

Oral fluid samples (1 mL) were collected from 72 participants using the Super•SAL Oral Fluid Collection Device (Oasis Diagnostics), but were tested using the SD Bioline Syphilis 3.0 rapid test (Alere Diagnostics) following manufacturer directions for whole blood. TP particle agglutination (TPPA) and rapid plasma reagin (RPR) results, abstracted from participants’ medical records, were used as reference values.

Assessing TPPA and RPR reactivity, the test had 86.4 percent sensitivity. Finally, using TPPA reactivity and RPR titer above 1:4, the test’s sensitivity was 100 percent. Specificity was 47.2 percent. The authors suggest that false positive results may be due to the presence of non-venereal treponemal antibodies in oral fluid.

“The high sensitivity of the SD Bioline Syphilis 3.0 test using oral fluid suggests a strong potential for the development of accurate rapid oral syphilis tests,” conclude the researchers, led by Chelsea Shannon.

Takeaway: CMS is expected to issue final rates in November. In the meantime, the laboratory industry has not given up on its efforts to persuade the agency to change the pricing formula to include hospital laboratories or delay the new PAMA rates from taking effect on Jan. 1, 2018.