Point-of-care testing in Ontario, 2007-2010 Ashleigh Sullivan, - - PowerPoint PPT Presentation

Point-of-care testing in Ontario, 2007-2010

Ashleigh Sullivan, Robert S. Remis, Carol Swantee Ontario Agency for Health Protection and Promotion Public Health Agency of Canada HIV Testing Conference Wednesday, May 11, 2011 Toronto

Overview of presentation

• POC testing summary
• Laboratory results
• POC test performance
• Epidemiology of HIV results
• Comparison of POC to standard testing

POC testing summary

• September 4, 2007 – April 26, 2010
• Number of tests 42,535, at 44 sites
• Range: 7–12,331 tests / site
• Average: 967, median: 33
• < 100: 14 sites
• 100-999: 19 sites
• ≥ 1,000: 11 sites
• Majority of sites began testing in 2008

POC tests by month

500 1,000 1,500 2,000 2,500

2007-Sep 2007-Nov 2008-Jan 2008-Mar 2008-May 2008-Jul 2008-Sep 2008-Nov 2009-Jan 2009-Mar 2009-May 2009-Jul 2009-Sep 2009-Nov 2010-Jan 2010-Mar

Year-Month Number of tests

POC tests by submission type

• Anonymous: 27,477 (64.6%)
• Coded: 14,346 (33.7%)
• Nominal: 712 (1.7%)

POC tests by age group and sex

Age (years) Male Female Sex unknown Percent male (%) < 20 890 1,309 43 40% 20-24 4,996 4,392 186 53% 25-29 5,830 3,648 152 62% 30-34 4,104 1,862 99 69% 35-39 3,222 1,100 69 75% 40-44 2,394 732 55 77% 45-49 1,804 487 55 79% 50+ 2,373 557 45 81% Unknown 1,019 835 277 55% Total 26,632 14,922 981 64%

Distribution by age group and sex

• Overall, 64% of testers were male
• Proportion male increased with increasing age,

from 40% among those < 20 years old to 81% among those 50+ years of age

• Highest proportion of testers were 20-29 years of

age (45%), followed by 30-39 years of age (25%) and 40-49 years of age (13%)

POC tests by region

Region Number % Northern 1,653 4 Ottawa 8,811 21 Eastern, other 364 1 Toronto 19,771 46 Central East, other 4,009 9 Central West 4,907 12 Southwest 2,975 7 Unknown 45 0.1 Total 42,535 100

Test results

• Total POC tests: 42,535
• Reactive: 462
• Non-reactive: 41,709
• Window period: 364

Reactive POC tests sent for Confirmatory testing

• Reactive tests: 462
• No sample available: 23
• Sent for confirmatory testing: 439
• Confirmed HIV-positive* : 306
• Confirmed HIV-negative: 126
• Indeterminate: 7* *

* Includes 9 specimens with previous positive result * * 6 followed up, all confirmed HIV-negative

Confirmed HIV-positive tests

Result interpretation Number % Early seroconverter (ESC) 4 1% Recent seroconverter (RSC) 33 11% Seroconverter (SC) 162 55% Weak positive (WP) 5 2% Positive (P) 93 31% Previous positive (P2) 9

• Total

306 100%

Confirmatory testing of window period POC tests

• Sent for confirmatory testing: 364
• Confirmed HIV-positive: 0
• Confirmed HIV-negative: 358
• Indeterminate: 6*

* 5 followed up, all confirmed HIV-negative

Symptoms for window period tests

Symptom Number % Suspected acute seroconversion 112 31% AIDS 0% Other HIV-related diseases 0% Other medical conditions 15 4% None 210 58% Not indicated 27 7% Total 364 100%

HIV positivity by year

Year HIV-positive Tested % 2007 13 1,104 1.18% 2008 112 13,372 0.84% 2009 124 20,942 0.59% 2010 48 7,112 0.67% Total 297 42,535 0.70%

Test specificity by year

Year Non-reactive POC Non-reactive POC and HIV-negative Specificity % 2007 1,085 1,085 100.0% 2008 13,078 13,116 99.7% 2009 20,564 20,620 99.7% 2010 6,982 7,014 99.5% Total 41,709 41,835 99.7%

Reactive POC tests confirmed HIV-negative

Year “False positive” Tested % 2007 1,104 0.00% 2008 38 13,372 0.28% 2009 56 20,942 0.27% 2010 32 7,112 0.45% Total 126 42,535 0.30%

HIV positivity by age group and sex

Age group Male Female Unknown < 20 0.2% 0.0% 0.0% 20-24 0.6% 0.1% 0.0% 25-29 1.0% 0.1% 0.7% 30-34 1.1% 0.3% 0.0% 35-39 1.1% 0.2% 1.5% 40-44 1.7% 1.1% 0.0% 45-49 1.9% 0.6% 1.8% 50+ 0.9% 0.2% 0.0% Unknown 0.0% 0.0% 0.0% Total 1.0% 0.2% 0.3%

HIV positivity by year and exposure category, Sep 2007 – Apr 2010

MSM IDU Endemic Hetero Other

T % T % T % T % T %

2007

482 2.1 3 0.0 11 0.0 572 0.4 35 2.9

2008

3,544 2.4 186 2.2 139 2.2 8,259 0.2 974 0.4

2009

5,146 2.0 305 2.0 235 0.9 13,515 0.1 1,740 0.1

2010

1,828 1.9 116 0.9 83 2.4 4,469 0.2 614 0.3

Total

11,000 2.1 610 1.8 468 1.5 27,085 0.1 3,363 0.2

HIV positivity by region

Region HIV-positive Tested % Northern 5 1,653 0.3% Ottawa 29 8,811 0.3% Eastern, other 1 45 2.2% Toronto 225 19,771 1.1% Central East, other 6 4,009 0.2% Central West 15 4,907 0.3% Southwest 16 2,975 0.5% Total 297 42,535 0.7%

Tests by exposure category, POC vs standard testing

POC testing Standard testing % Tested % Tested LR Hetero 61.5% 75.0% MSM 25.3% 5.4% Other 8.0% 8.7% HR Hetero 2.6% 3.6% IDU 1.5% 4.5% HIV-endemic 1.1% 3.0% MSM-IDU 0.1% 0.3%

HIV positivity, POC vs standard testing, Jan 1, 2008 – Mar 31, 2010

POC testing Standard testing P-value P % P % MSM

214 2.1% 900 1.8% 0.08

MSM-IDU

1 1.9% 65 2.1%

• IDU

11 1.9% 165 0.4% < 0.001

HIV-endemic

7 1.6% 485 1.8% 0.08

HR Hetero

10 1.0% 104 0.3% < 0.001

LR Hetero

26 0.1% 334 0.05% < 0.001

Other

7 0.2% 59 0.1% 0.07

Total

276 0.69% 2,112 0.23% < 0.001

HIV positivity by submission type, POC vs standard testing

POC Standard P T % P T % Anonymous

251 27,552 0.91% 78 5,889 1.3%

Coded

25 14,346 0.17% 255 41,532 0.61%

Nominal

21 637 3.3% 2,175 1,020,893 0.21%

Total

297 42,535 0.70% 2,508 1,068,314 0.23%

Summary and interpretation

• POC testing
• 2/3 were male
• 75% were 20-39 years of age
• 64% were heterosexual and 26% MSM
• Laboratory results
• 462 (1.1%) of tests were reactive at the site.
• Of 462 reactive tests, 306 (70%) confirmed HIV-positive

Summary and interpretation cont’d

POC test performance

• No window period samples confirmed HIV-positive
• 126 POC reactive tests confirmed HIV-negative

Epidemiology of HIV results

• HIV-positivity rate highest for:
• 40-49 years of age (1.6%)
• MSM (2.1%) followed by IDU (1.9%)

and HIV-endemic (1.6%)

• Toronto (1.14%)

Summary and interpretation cont’d

Comparison of POC to standard testing

• POC tests more high risk patients (33% vs 17%)
• POC positivity rate is 3-fold higher (0.70% vs 0.23%)
• Higher positivity rates in POC explained by two factors:
• Higher proportion of anonymous tests (65% vs 0.6%)
• Increase in the absolute number of anonymous tests

Acknowledgements

• Staff at Point-of-care sites who completed HIV

requisitions

• Personnel, Public Health Laboratory – Toronto,

Ontario Agency for Health Protection and Promotion

• Public Health Agency of Canada,

Field Surveillance Officer Program

• Carol Major and the AIDS Bureau who support POC

and provided advice