HIV Surveillance Case Definition
Position Statement #12-ID-05
Overview
CSTE Meeting
June 3, 2012
Omaha, Nebraska
Eve D. Mokotoff
Proposed Revisions









New HIV testing algorithms
New: criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD - date of diagnosis
Proposed Revisions









New HIV testing algorithms
New: criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD - date of diagnosis
New HIV Testing Algorithms (slide 1)

HIV cases should include persons with positive
conclusions from any testing algorithm
recommended by Criteria for Laboratory Testing and
Diagnosis of Human Immunodeficiency Virus
Infection: Approved Guideline, [CLSI document M53A, ISBN 1-56238-758-8], published June 2011 by
Clinical and Laboratory Standards Institute

Cases based on a presumptive positive result of a
CLSI algorithm should not be distinguished from
cases based on a definitive result in surveillance
tabulations
Why are we Suggesting this Change?
The CLSI document describes algorithms that
clinicians and labs are already using
 We are making these changes so we can have
the infrastructure in place to allow reporting
of cases diagnosed using these new
algorithms
 We are not driving clinical practice- we are
adapting surveillance to account for changes
that are occurring

Why are we Suggesting this Change?
(cont)

If we fail to develop a way to recognize cases
diagnosed using the new algorithms we will
undercount cases
 as use of the new algorithms increases the
number of cases we would lose increases

Implementation is complex but necessary
Progression of HIV Viral Markers
IgG
IgM
Acute
Das G et al. BMJ 2010;341:bmj.c4583
Seroconversion→Established
7
New HIV Testing Algorithms (slide 2)

What is new about the new algorithms?
 Results of more sensitive and specific antibody tests
formerly used only as initial tests for screening (e.g.,
immunoassays such as EIAs and rapid tests) may
now be used as supplemental tests to confirm a case
of HIV-infection after a positive result on another
immunoassay
Relative Sensitivity of Tests
From: Branson, JAIDS, 2010, 55 (S2): S102-S105
9
New Testing Algorithms (slide 3)

Labs and healthcare providers may need guidance on
how to report results from new multi-test algorithms
to surveillance programs.
 Labs may need to report results of both first and
subsequent test(s) in algorithm, not just final test
 Surveillance needs way to know both tests were part
of same algorithm, not just unrelated screening tests

We expect implementation issues to be resolved by a
workgroup that consists of representatives from
areas with established lab reporting systems and CDC
staff.
Proposed Revisions









New HIV testing algorithms
New: criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD - date of diagnosis
Suspect Case Criteria

Cases meeting the following criteria should be
reported for follow-up and confirmation:
 4th gen IA positive (Ag/Ab test)
 F/U antibody-only test is negative
 NAT (normally used to confirm results above) is
unavailable

Conclusion - case may be antigen positive/
antibody negative
Suspect Case - Rationale
Cases meeting criteria may represent acute HIV
infection
 Highly infectious - high viral loads
 May not know their HIV status
 High priority for follow-up by health department
to obtain second specimen for NAT testing (if
possible), notify of potential infectiousness, start
partner notification process, refer into care for
further testing and follow-up

Suspect Case - Concerns
Cases meeting criteria may be false positives
 Sensitivity and specificity of 4th generation IA is
>99% (higher than the Western Blot we have
been using to confirm cases as positive since the
1980s) so do not expect many false positives
 If case is falsely positive sending health
department out to obtain second specimen for
NAT testing/refer patient to care for follow up
testing will determine status

 If HD unable to obtain NAT results, case can be
changed to negative if received in the future
Suspect Case – Concerns
(cont)

Are we expecting states to start routine collection
of negative results?
NO
We do not want nor expect all negative results to
be reported BUT if the 4th gen IA was + we would
want negative results on antibody tests associated
with that + reported if possible
 We expect we will learn of these cases primarily
from reports from clinicians who encounter them

 Will know more as use of new lab tests increases
Suspect Case – Concerns
(cont)

Inclusion of these cases in the case definition
is to:
 help states emphasize the importance of such
cases and
 give them the support to be able to report them

Inclusion of these cases is not required
Suspect Case - Steps Needed to
Include in Position Statement
Not included in PS#12-ID-05 as submitted on
March 29, 2012
 Is included in June 1 version of the Position
Statement (posted on CSTE website)

 Addition is in section VII- Case Definition for Case
Classification A.3 and A.3.a and Table VII-B.3
Suspect Case - Why Now?
Work groups and consultation on integrating new
testing algorithms occurred before testing using
new algorithms widely implemented
 Once implementation began we realized that
commercial labs would likely require a second
blood draw with specimen received within 72
hours for confirmatory NAT testing
 Lab reality: second draws occur infrequently
and/or specimens not received within 72 hours
 Consequently, need a process for cases described
above and shown again in next slide

Suspect Case Criteria

Cases meeting the following criteria should be
reported for follow-up and confirmation:
 4th gen IA positive (Ag/Ab test)
 F/U antibody-only test is negative
 NAT (normally used to confirm results above) is
unavailable

Conclusion - case may be antigen positive/
antibody negative
Proposed Revisions









New HIV testing algorithms
New: criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD - date of diagnosis
HIV-2 Infection

HIV case surveillance should accept as sufficient for
diagnosis of HIV-2 infection:
 Positive initial test that can detect HIV-2 antibody
(e.g., HIV-1/2 immunoassay) AND
 One or more of the following:
• FDA-approved HIV 1/2 type-differentiating antibody
test positive for HIV-2 and negative for HIV-1 or
• Positive HIV-2 nucleic acid test (NAT) or
• Positive HIV-2 Western blot/immunoblot (WB) and
negative HIV-1 WB or
• Diagnosis by CDC-recognized expert in WB
interpretation if positive HIV-2 WB and positive or
indeterminate HIV-1 WB
Proposed Revisions









New HIV testing algorithms
New criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD- date of diagnosis
Stage 0 HIV Infection (slide 1)
First confirmed positive HIV test
(confirmed Ag/Ab positive or NAT)
180 days
30 days
OR
Negative or
indeterminate HIV
antibody test or
negative/undetectable
NAT/viral load
Negative or
indeterminate HIV
antibody test
followed by
positive NAT
Stage 0 HIV Infection (slide 2)
Exceptions
 These criteria for Stage 0 do not apply to HIV-2
 Stage 0 does not last >180 days after diagnosis date
 Stage 0 is excluded if first positive test was preceded by
>60 days by evidence of long-standing infection:
 CD4 T-lymphocyte count <200 cells/µL
 Physician documented diagnosis
Otherwise, Stage 0 criteria are independent of CD4 Tlymphocyte test results and take precedence over criteria
for other HIV stages
Expectations of Health Departments


This Position Statement does not imply that we expect you
to start obtaining all negative reports-clearly a problem for
most/all of us
Identifying an acute case will likely come from physicians or
other testers and this definition is to allow us to capture
these critically important cases
Proposed Revisions









New HIV testing algorithms
New: criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD - date of diagnosis
AIDS-Defining Conditions
(Opportunistic Illnesses [OIs]) (slide 1)

OIs should be removed from criteria for Stage 3 (AIDS) in
future staging among adults/adolescents, because
 CD4 data adequately substitute for OI data as criteria for
Stage 3
 More direct measure of immune system damage
 95% of cases meet Stage 3 criteria based on CD4 results
 Most systems do not routinely collect OI data- expensive
to collect
AIDS-Defining Conditions
(Opportunistic Illnesses [OIs]) (slide 2)

OIs should be removed from criteria for Stage 3 (AIDS) in
future staging among adults/adolescents, because
 OI data collected by routine surveillance are too
incomplete to be useful for analyzing OIs
 Other projects and surveillance systems do a better job of
collecting representative OI data than does routine HIV
case surveillance (MMP)
 Eliminating OIs from staging will simplify surveillance
AIDS-Defining Conditions
(Opportunistic Illnesses [OIs]) (slide 3)

OIs should be kept as criteria for Stage 3 in children
because CD4’s are not being used as criteria for Stage
3 in children, but
 Whatever method was used to make an OI diagnosis
should be accepted as sufficient for surveillance
(eliminating requirement that some OIs be
“definitively” diagnosed)
 Lymphoid interstitial pneumonia should be removed
from the list because it is associated with moderate
rather than severe immunodeficiency
Proposed Revisions









New HIV testing algorithms
New: criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD - date of diagnosis
CD4 Test Results as Criteria for Staging
in Adults/Adolescents

CD4 count should take precedence over CD4 percentage
as criterion for staging; CD4 percentage should be
criterion only if CD4 count is missing
Reasons:
 Clinicians consider CD4 count to have greater
prognostic value than CD4 percentage
 Some studies show CD4 percentage has little effect on
prognosis after adjusting for CD4 count

CD4 percentage used as threshold between
Stages 1 and 2 should be 26% instead of 29% (if data
supporting this change are published)
Other Staging Issues


Use of term “AIDS” should be minimized in staging
system (just call it “Stage 3”)
Permit alternative applications of staging system:
 most severe stage experienced as of a particular date
(for which changes in stage could be in only one
direction--from less to more severe)
 stage at initial diagnosis
 stage based on most recent CD4 test results (for which
changes could be in either direction, including from
more to less severe); (excluding Stage 0 because not
based on CD4 test results)
Proposed Revisions









New HIV testing algorithms
New: criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD - date of diagnosis
HIV Infection Case Definition for Children

For a diagnosis of HIV infection among children
under 18 months of age,
 Remove 2008 case definition’s requirement of HIV-infected
mother for
• Definitive HIV infection and
• Presumptive HIV infection
because laboratory test results can be sufficient to make
those diagnoses,
 but keep requirement of HIV-infected mother for
indeterminate HIV infection, where required lab results are
unavailable for definitive or presumptive diagnosis, and
 for determination of absence of HIV infection among
perinatally HIV-exposed children
Proposed Revisions









New HIV testing algorithms
New: criteria for a suspect case
HIV-2 infection
Stage 0 HIV infection
AIDS-defining conditions (opportunistic illnesses)
CD4 test results for staging for adults/adolescents
HIV Case definition for children
Physician-documented diagnosis- PDD (clinical ,
rather than laboratory criteria for a confirmed case)
PDD - date of diagnosis
Clinical Criteria for Confirmed HIV Case
(Physician-Documented Diagnosis) (slide 1)

If physician’s written statement says patient had
 positive result
 on a particular type of HIV test
 in a specific year
(not stated to be only what patient said),
then diagnosis should be considered
laboratory-test-documented, not physiciandocumented (i.e., meets lab criteria, not clinical
criteria)
Clinical Criteria for Confirmed HIV Case
(slide 2)

If initial diagnosis is not laboratory-testdocumented, but
 physician’s note says patient has HIV infection (not
stated to be only what patient said),
and
 subsequent diagnosis is laboratory-test-documented
or
 there is circumstantial evidence of HIV infection (with
other explanations ruled out), such as
• Receipt of HIV-related care (e.g., antiretrovirals, OI
prophylaxis, repeated CD4 tests and viral loads)
• CD4 count <350 cells/µL
• OI diagnosis
then initial diagnosis is physician-documented
Date of Physician Documented Diagnosis


Official date of diagnosis should be defined as:
Date of diagnosis reported in physician’s note, even
if inaccurate or inexact, not necessarily date on
which note was written unless diagnosis date (year)
was not reported in note
However, all dates should be collected, including
 Diagnosis date reported by physician (not stated
to be reported by patient)
 Diagnosis date stated to have been reported by
patient
 Date note was written by physician
Many thanks to CDC’s Richard Selik for all the work he
did on this Position Statement: the initial writing and
research, working with the workgroups which informed
the decisions made at the February 2012 case
definition consultation and on which this PS is based.
Eve Mokotoff Contact Info
Eve Mokotoff, MPH
MokotoffE@michigan.gov
(V) 313.876.4769 (0353)
(C) 313.407.7761
HIV/STD/VH/TB Epidemiology Section
Michigan Department of Community Health
1151 Taylor Room 211B
Detroit, MI 48202