Publications

To design instructional methods that would promote long-term retention of knowledge of antimicrobial pharmacology, particularly the spectrum of activity for antimicrobial agents, in pharmacy students. An active-learning approach was used to teach selected sessions in a required antimicrobial pharmacology course. Students were expected to review key concepts from the course reader prior to the in-class sessions. During class, brief concept reviews were followed by active-learning exercises, including a novel schematic method for learning antimicrobial spectrum of activity ("flower diagrams"). At the beginning of the next quarter (approximately 10 weeks after the in-class sessions), 360 students (three yearly cohorts) completed a low-stakes multiple-choice examination on the concepts in antimicrobial spectrum of activity. When data for students was pooled across years, the mean number of correct items was 75.3% for the items that tested content delivered with the active-learning method vs 70.4% for items that tested content delivered via traditional lecture (mean difference 4.9%). Instructor ratings on student evaluations of the active-learning approach were high (mean scores 4.5-4.8 on a 5-point scale) and student comments were positive about the active-learning approach and flower diagrams. An active-learning approach led to modestly higher scores in a test of long-term retention of pharmacology knowledge and was well-received by students.

BACKGROUND

The Determine™ HIV-1/2 Ag/Ab Combo (DC) rapid test can identify HIV-1 infection earlier than rapid antibody-only tests in plasma specimens.

OBJECTIVES

We compared the performance of DC with a laboratory-based antigen/antibody (Ag/Ab) combo assay in plasma and evaluated antigen reactivity in whole blood specimens.

STUDY DESIGN

We tested by DC 508 plasma specimens collected in a prospective study and 107 sequential plasma and simulated whole blood specimens from 20 seroconversion panels. Previous results using the ARCHITECT (ARC) Ag/Ab combo assay were compared to DC results. In seroconversion panels, the days from the first HIV1 RNA-positive test to first DC-reactive in plasma and whole blood was compared. McNemar's and Wilcoxon signed rank tests were used for statistical analysis.

RESULTS

Of 415 HIV-positive samples, ARC detected 396 (95.4%) and DC 337 (81.2%) (p<0.0001). DC was reactive in 50.0% of ARC-reactive/MS-negative, 78.6% of ARC-reactive/MS-indeterminate, and 99.6% of ARC-reactive/MS-HIV-1-positive or -undifferentiated specimens. DC antigen reactivity was higher among ARC-reactive/MS-negative than MS-indeterminate samples. In 20 HIV-1 seroconversion panels, there was a significant difference between DC reactivity in plasma (91.1%) and whole blood (56.4%) (p<0.0001). DC with whole blood showed a significant delay in reactivity compared to plasma (p=0.008).

CONCLUSIONS

In plasma, DC was significantly less sensitive than an instrumented laboratory-based Ag/Ab combo assay. DC in plasma was significantly more sensitive compared to whole blood in early HIV-1 infections. With the U.S. laboratory-based diagnostic algorithm, DC as the first step would likely miss a high proportion of HIV-1 infections in early stages of seroconversion.