Development of a proficiency testing program for the HIV-1 BED incidence assay in China

Abstract

The HIV-1 BED incidence assay was adopted in China in 2005 for HIV-1 incidence surveillance. A proficiency testing (PT) program was established in 2006 to provide quality assurance services. The BED PT program consisted of two components, an international program provided by the U.S. Centers for Disease Control and Prevention from 2006 and a domestic program started by the National HIV/HCV Reference Laboratory in 2011. Each PT panel consisted of eight coded specimens distributed to participating laboratories semi-annually, and testing results were collected and analyzed. The number of participating laboratories increased progressively from 2006 to 2012. The Chinese HIV-1 incidence laboratory network performed satisfactorily both in international and domestic PT programs. We also demonstrated that the BED assay was highly reproducible among participating laboratories. Our success and lessons learned can be readily replicated in other countries or regions contemplating the establishment of a PT program for assay-based HIV incidence estimation.

Figure 1. Participation and performance of laboratories of China in the international BED PT program over 13 rounds (a) and in the domestic BED PT program over 3 rounds (b).

Figure 2. Concordance of mean obtained results with expected results for 13 international BED PT rounds (n = 104) and 3 domestic BED PT rounds (n = 24).

Regression analysis: correlation of expected ODn results and Mean ODn results. The best-fit regression line is shown for each PT program. Vertical and horizontal arrows indicate 0.8 cutoffs. Mean ODn results vs. expected ODn results for all participants (a); participants using kits from different manufacturers during international PT (88 Calypte kits, 40 Sedia kits) (b); participants using kits from different manufacturers during domestic PT (Calypte kits, n = 8; Sedia kits, n = 24) (c). Bland-Altman analysis: correlation of expected ODn results and Mean ODn results for international PT program (d) and domestic PT program (e).

Figure 3. Overall concordance from all participating laboratories between the initial and confirmatory runs for 786 results during international PT rounds and 451 results during domestic PT rounds.

Regression analysis (a and b) and Bland-Altman analysis (c and d) for international and domestic PT program, respectively. For each PT program, the best-fit regression line is shown with statistics in the upper left (a and b). Four results with large different initial and confirmatory ODn are indicated by open circles (b and d).

Figure 4. Performance characteristics of duplicated specimens in the international PT program rounds, with black and white bars representing the specimen replicates.

Mean ODn with standard deviation (SD) of all participating laboratories (a), laboratories using Calypte kits (b), and laboratories using Sedia kits (c). Sedia kits became available in 2010. In round 13 of the international BED PT program and round 3 of the domestic BED PT program, all participating laboratories used Sedia kits except one. The results from that laboratory in these two rounds were not included.