Joanne Stekler, MD MPH

Associate Professor

University of Washington

December 5, 2016

Point-of-care HIV testing

Disclaimer: The findings and conclusions in this presentation are those of the author(s) and do

not necessarily represent the views of the Division of HIV/AIDS Prevention at the Centers for

Disease Control and Prevention.

Objectives

1. Learn about advantages and disadvantages of point-of-care HIV tests.

2. Learn about issues re: point-of-care HIV testing in context of pre-exposure prophylaxis (PrEP).

Fiebig et al. AIDS, 2003 Sep 5; 17(13): 1871-9

HIV test Method Window

1st gen EIA (Ab) viral lysate ~ 4-6 wks

2nd gen EIA (Ab) purified HIV-1/2 Ag or recombinant

~ 3-4 wks

3rd gen EIA (Ab) synthetic peptide,

“antigen sandwich”

detects IgM

~ 2-3 wks

4th gen assay

(Ab plus p24 Ag)

detects either antibody or p24 Ag

~ 2 wks

Pooled HIV RNA (HIV NAAT)

<1-2 wks

Adapted from Stekler CID 2007

Oraquick Advance Chembio Sure Check

Chembio Stat PakINSTI HIV 1/2

DPP HIV 1/2

Uni-Gold Recombigen

Slide courtesy of Bernie Branson

Determine HIV-1/2 Ag/Ab Combo (Alere)

Advantages

• Patient Preference?

• Potential Avoidance of Blood Draw/ Biohazard

• More Persons Receive Results

• Potential for Preliminary False-Positive Results

• Longer window period

Disadvantages

# HIV-positiveCumulative HIV-

positiveCumulative “Sensitivity”

OraQuick 314 (2.0%) 314 77%

EIA 40 (0.3%) 354 87%

NAAT 52 (0.3%) 406 100%

Modified from Masciotra et al, J Clin Virol 2011

and Owen et al, J Clin Micro 2008

Slide courtesy of Bernie Branson

Days before WB positive

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POC tests (each test on separate fingerstick)

OraQuick (oral fluids and fingerstick)

Uni-Gold or INSTI

Determine HIV-1/2 Ag/Ab

EIA

PHSKC: 3rd gen Genetic Systems HIV-1/HIV-2 Plus O EIA

PIC: 4th gen Abbott ARCHITECT HIV Ag/Ab Combo assay

NAAT

PHSKC: 27-specimen master pools (3x3x3 matrix)

Abbott RealTime HIV-1 RNA assay

McNemar’s exact tests compared numbers of cases detected

STD Clinic & Gay City

n=3404

PIC

n=34

Total

n=3438

Concordant Positive POC Tests 82 (77%) 18 100

Discordant POC Antibody Tests 10 (9%) 13 23

All POC Negative/EIA Positive 6 (6%) 0 6

Acute (EIA Neg / NAAT Pos) 9 (8%) 2 11

Total HIV Positive 107 (3.1%) 33 140

Stekler, J Clin Virol 2016; Stekler, J Clin Virol 2013; O’Neal, JAIDS 2012

# tested # AHI detected

Taegtmeyer PLoSOne 2011 UK 953 none

Rosenberg JID 2012 Malawi 838 0/8

Kilembe PLoSOne 2012 Rwanda, Zambia 1/52

Conway PLoSOne 2014 Australia 3190 0/9

Duong J Clin Microbiol 2014 Swaziland 18,172 0/13

Stekler J Clin Virol 2016 US 3438 1/11

>26,591 2/93

N tested Specificity (95% CI)

OraQuick (oral fluid) 2109/2112 = 99.86% (99.59-99.97)

OraQuick (fingerstick) 2107/2107 = 100% (99.82-100)

Uni-Gold 1561/1561 = 100% (99.76-100)

INSTI 543/544 = 99.82% (98.98-100)

Determine Combo 1468/1483 = 98.99% (98.34-99.43)

GS HIV-1/HIV-2 Plus O antibody (EIA) 2091/2095 = 99.81% (99.51-99.95)

Stekler, J Clin Virol, 2016

Meta-analysisOverall pooled specificity (plasma, serum, WB) 99.1% (97.3-99.8)Smallwood et al. PLoS One 2016 11(2)

• Point-of-care HIV tests are not all the same.

• Oral fluid is significantly inferior and should be the

specimen type of last resort.

• Determine Combo, although a 4th generation POC test, is

not equivalent to lab-based testing when looking for AHI.

– But it still may pick up a case or two….

• Other factors may impact device choice

– Cost

– Time (1 minute v 20-30 minutes)

– Blood volume (5 v 50µL)

• When starting PrEP, use the test with shortest window

period available. Do not use oral fluid tests.

(starting PrEP during AHI → resistance)

• Do not ask people to remain abstinent/use condoms while

waiting out the window period.

• Screen for symptoms of AHI

– If symptoms and recent exposure → delay PrEP start

– *Almost all* symptomatic AHI will test pos on lab 4th gen

But…. There is a 2nd window period….

• PrEP may lead to delayed seroconversion and false-

negative tests, particularly with oral fluid tests.

HIV testing in PrEP

Analysis of False Negative HIV Tests Based on Oral Fluid in 3 Clinical

Trials (Curlin, CROI 2016, #635)

- 208 false negative OQOF results among 28% of 290 seroconverters.

- Median OQOF reactivity delay time was 98 (range 14-547) days.

The Effect of Oral Pre-exposure Prophylaxis on the Progression of HIV-1

Seroconversion (Donnell, HIVR4P 2016, #OA03.01)

- 138 seroconversions

- Slight delay in Fiebig progression and delayed detection in some using

fingerstick HIV tests