understanding hiv diagnostics and lab tests

1

Understanding Diagnostics and Lab Tests in the Management of HIV Disease

2

Objectives

• Increase awareness of the importance of regular lab testing in the management of HIV disease

• Discuss how diagnostics/lab tests, approved and in development, may be used in the management of HIV disease

• Provide an overview of diagnostic tests commonly used by health care providers in the management of HIV disease

3

HIV Treatment Today and Tomorrow

• There has been a great deal of research to better understand and treat HIV

• Advances in medications and lab tests have revolutionized the detection, monitoring, and management of HIV

• With about 30 HIV drugs available, including combination medications, people with HIV are living longer and healthier lives

• More drugs and diagnostic tools that work in new and different ways are coming online

• Increasingly, HIV treatment can offer the hope of better health

Today Tomorrow

FDA. Drugs used in the treatment of HIV infection. Available at: http://www.fda.gov/oashi/aids/virals.html.

4

The HIV Life Cycle

..

Step 1Viral Entry

Step 2Reverse

Transcription

Step 4Transcription and

Translation

Step 5Assembly and

Budding

Step 3Integration

HIV reproduces inside the CD4+ T-cell

Viral RNA

gp 120

CD4 Receptor

Co-receptor(CCR5 or CXCR4)

New HIV Particle

Viral ProteinsViral DNANucleus

Cell DNA

CD4+ T-Cell

Hoffmann CJ, Gallant JE. Infect Dis. 2007;33:1-33.

5

Viral RNA

gp 120

CD4 Receptor


New HIV Particle


Cell DNA

CD4+ T-Cell

The HIV Life Cycle

Step 1Viral Entry

Step 2Reverse

Transcription


Translation

Step 5Assembly and

Budding

Step 3Integration


6

Viral RNA

gp 120

CD4 Receptor


New HIV Particle


Cell DNA

CD4+ T-Cell

The HIV Life Cycle

...

Step 1Viral Entry

Step 2Reverse

Transcription


Translation

Step 5Assembly and

Budding

Step 3Integration


7

Viral RNA

gp 120

CD4 Receptor


New HIV Particle


Cell DNA

CD4+ T-Cell

The HIV Life Cycle

Step 1Viral Entry

Step 2Reverse

Transcription


Translation

Step 5Assembly and

Budding

Step 3Integration


8

Viral RNA

gp 120

CD4 Receptor


New HIV Particle


Cell DNA

CD4+ T-Cell

The HIV Life Cycle

Step 1Viral Entry

Step 2Reverse

Transcription


Translation

Step 5Assembly and

Budding

Step 3Integration


9

Viral RNA

gp 120

CD4 Receptor


New HIV Particles


Cell DNA

CD4+ T-Cell

The HIV Life Cycle

..

Step 1Viral Entry

Step 2Reverse

Transcription


Translation

Step 5Assembly and

Budding

Step 3Integration


10

Advances in Treatment and Lab Tests

Early1980sEarly1980s

Mid1980sMid

1980sLate

1980sLate

1980sEarly1990sEarly1990s

Mid1990sMid

1990sLate

1990sLate


HAART 2HAART 2ART EraART EraPre-ART EraPre-ART Era TodayTodayHAART 1HAART 1

20082008

11

Monotherapy and dual therapy Protease inhibitors,1st DHHS treatmentguidelines

New formulations and combinationsto reduce number

of pills,1st fusion inhibitor

CCR5 antagonists,

integrase inhibitors

Effective prophylaxis

for life- threatening OIs

AZT used to prevent

mother-to-child transmission


Mid1980sMid

1980sLate

1980sLate


Mid1990sMid

1990sLate

1990sLate



20082008


ART = antiretroviral therapy; AZT = zidovudine; OIs = opportunistic infections; HAART = highly active antiretroviral therapy;

DHHS = Department of Health and Human Services.

FDA. HIV/AIDS historical time line. Available at: http://www.fda.gov/oashi/aids/miles.html.

12

Monotherapy and dual therapy Protease inhibitors,1st DHHS treatmentguidelines

New formulations and combinationsto reduce number

of pills,1st fusion inhibitor

CCR5 antagonists,

integrase inhibitors

Effective prophylaxis

for life- threatening OIs

AZT used to prevent

mother-to-child transmission


Mid1980sMid

1980sLate

1980sLate


Mid1990sMid

1990sLate

1990sLate



Treatment decisions primarilybased on CD4+ T-cell count

VL testingHIV isolated, 1st HIV antibody test

OraQuick rapid test

Genotype and phenotype resistance tests

Tropism test,entry inhibitor test,integrase inhibitor

testOraSure test

Sensitive VL tests (<400, <50)

20082008


VL = viral load.

FDA. HIV/AIDS historical time line. Available at: http://www.fda.gov/oashi/aids/miles.html.

13

Summary

• Understanding the HIV life cycle has helped researchers develop new and improved drugs to fight HIV

• Drugs used to treat HIV prevent the virus from reproducing by stopping it at different points in its life cycle

• HIV treatment and care options, including new drugs and lab tests, are evolving

• Today, new classes of drugs are available that work in different ways

14

Why Are Lab Tests Important?

DHHS. Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents. Washington, DC: Office of AIDS Research Advisory Council, US Dept of Health and Human Services; December 1, 2007.

• Current lab tests look at 3 key areas: • Lab tests help health care providers:

The Immune System andResponse to Treatment

– Determine when to start treatment– Evaluate response to treatment– Determine when to switch treatments

1

The Virus2

– Determine which drugs to use

Overall Health3

– Determine if drugs are causing side effects or toxicities

15

Starting Point


1

The Virus2

Overall Health3

• Determine HIV status • Baseline tests

16

Starting Point



– CD4+T-cell count– VL

1

The Virus2

– Drug resistance testing if VL>1000

• Determine HIV status • Baseline tests

Overall Health3 – Chem screen

– Complete blood count– Liver function tests– Pap test

– STD tests– Hepatitis tests– Opportunistic infection tests:

toxoplasmosis, tuberculosis

Chem = chemical; STD = sexually transmitted disease.

17

• Test values are usually given as a range or reference

• Lab tests show whether results are in the normal range

• Normal range will depend on individual factors including age, race/ethnicity, gender

• An out-of-range test result may not signal a major problem

• Trends over time are more important

• Discuss lab test results with a health care provider

Understanding Lab Work

HighLow Normal Range

18

Key Questions

• 3 important questions to ask the health care provider about lab tests:

1. Why is this test important?

2. How often should I have it done?

3. What do the results mean and how do they affect my health and HIV treatment?

19

Tests That Tell About The Immune System andResponse to Treatment

1

20

Goals of TreatmentGoals of Treatment

Low VL

CD4+ T-Cell Count and Viral Load

High CD4+ T-Cell Count

• CD4+ T-cell count and VL are related to 2 main goals of HIV treatment


VL <50 copies/mL forTreatment Naïve and

Treatment Experienced

21

Test Goal of Treatment Results What It Means

CD4+ T-Cell Count Measures how many CD4+ T-cells are circulating in the bloodstream

>500 cells/mm3

Immune system is relatively health

350-500 cells/mm3

Best time to initiate therapy in asymptomatic patients is not well defined;

<349 cells/mm3

Increased risk of some illnesses; HIV treatment recommended

<200 cells/mm3

AIDS diagnosis – increased risk of opportunistic infections; preventive therapy for opportunistic infections may be needed

High CD4+ T-Cell Count

CD4+ T-Cell Count


22

CD4+ T-Cell Count Is a Key Factor in Determining When to Start Treatment

• CD4+ T-cell count is key in deciding when to start treatment

• A branch of the government called the Department of Health and Human Services, or DHHS, publishes guidelines for the treatment of HIV

Lab Results Recommendation

CD4+ T-cell count >350 cells/mm3 Risks and benefits of treatment should be taken into consideration

CD4+ T-cell count <350 cells/mm3 Start treatment

CD4+ T-cell count of any value

Treat all:

• Pregnant women

• People with HIV-associated kidney disease

• People coinfected with hepatitis B (HBV) who require HBV treatment


23

Test Goal of Treatment What It Means

VL

Measures the amount of HIV circulating in the bloodstream

• May be a consideration in the decision to initiate therapy

• Critical for evaluating the response to therapy

• Undetectable (goal)

VL<50 for Treatment Naïve and Treatment

Experienced

Viral Load


24

Viral Load

Patient NameDOE, JOHN

Date Drawn12/20/06

Date Received12/20/06

Date of Report12/22/06

SexM

Client Name / AddressMEDICAL CENTERYOUR DOCTOR, MD123 MAIN STREETANYTOWN US 10023

Client I.D. Number78987456

Account Number12345

Age33

Ordering PhysicianSMITH123094789

Specimen Number123273

Time Drawn11:00 AM

Test Name Results Units Reference RangeHIV-1 RNA, PCR, 2ND GENHIV-RNA, PCRLOG COPIES/ML

885.0 H2.95 H

Copies/mLLog copies/mL

<50<1.7

Clinical Laboratory Report

Patient I.D./SSN12345/234-56-7890

25

Exercise: Sam Gets His Test Results

• Sam is a 30-year-old man recently diagnosed with HIV disease

• He just received his CD4+ T-cell count and VL test results

• Sam is confused and asks his case manager for help in understanding the lab results

• How would you explain CD4+ T-cell count and VL to Sam?

• What would you tell Sam is the most important information he needs to know about each test?

• What questions should Sam ask his health care provider about each test?

Sam’s Story Discussion

26

Tests for Learning More About The Virus

2

27

Resistance Testing

• Drug resistance means that HIV continues to multiply even when a person is taking HIV drugs

• When this happens, VL usually goes up and CD4+ T-cell count usually goes down – this may indicate that the medications are less effective

• Resistance tests are used to:– Check which drugs in a treatment regimen no longer work (or no longer work as

well)– Help determine which other drugs the virus will respond to

• The DHHS guidelines recommend resistance testing:– Before starting treatment– If starting treatment does not lead to undetectable VL– If undetectable VL becomes detectable while on medication

.DHHS. Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents. Washington, DC: Office of AIDS Research Advisory Council, US Dept of Health and Human Services; December 1, 2007.

28

Genotype Test

• Tests for virus mutations associated with resistance to a particular drug

• Recommended as 1st resistance test for people who are new to treatment

• Requires more interpretation than phenotype test

• Costs less and is more widely available than phenotype test

Genotype and Phenotype Tests

Phenotype Test

• Measures how well the virus can reproduce in the presence of different drugs

• Provides more information than genotype test about which drugs will work against your virus

• Easier to interpret than genotype test

• More expensive than genotype test


29

Exercise: Sam Gets a Resistance Test

• After having an undetectable VL for a number of years, Sam’s VL is now detectable

• Sam knows about drug resistance and calls a treatment hotline to ask about resistance tests

• How would you explain genotype and phenotype testing to Sam?

• What would you tell Sam is the most important information he needs to know about each test?

• What questions should Sam ask his health care provider about each test?


30

• Many lab tests that are commonly used today (such as VL) were first used in research settings such as clinical trials

• As these tests were shown to provide valuable information to help manage HIV, they became part of routine care

• Just as new drugs are continually being developed to improve care, new lab tests are continually being investigated

• Such tests may help to further individualize treatment and improve health outcomes

• Some of the new tests include:– Tropism test

– Entry inhibitor test

– Integrase inhibitor test

New Tests

31

Viral Entry Is a 3-Stage Process

• Tropism test focuses on the second stage of viral entry, called co-receptor binding

Poveda E, Briz V, Quiñones-Mateu M, Soriano V. AIDS. 2006;20:1359-1367.

Adapted from: Moore JP, Doms RW. Proc Natl Acad Sci USA. 2003;100:10598-10602. Copyright 2003 National Academy of Sciences, USA.

1. Attachment 2. Co-receptor Binding 3. Fusion

Cell Membrane CCR5/CXCR4

Fusion inhibitorsCCR5 antagonistsgp41

CD4 bindinginhibitors

gp120

32

Tropism Test

• The tropism test determines which co-receptor HIV uses to enter CD4+ T-cells

– CCR5 (CCR5-tropic virus)

– CXCR4 (CXCR4-tropic virus)

– CCR5 and CXCR4 (dual- or mixed-tropic virus)

• The tropism test identifies which people may benefit from co-receptor antagonists

– These drugs inhibit HIV from using a co-receptor to enter a CD4+ T-cell – this prevents HIV from infecting the cell

– A tropism test can inform a health care provider about whether or not a patient may benefit from a co-receptor antagonist

Poveda E, Briz V, Quiñones-Mateu M, Soriano V. AIDS. 2006;20:1359-1367.

33

Tropism Test Results

• You and your doctor may consider if a CCR5 antagonist is right for you

• According to the DHHS treatment guidelines, a tropism test should be performed whenever the use of a CCR5 antagonist is being considered

• Blood is drawn for a tropism test and results are provided within 2 weeks after the lab receives the sample

• Results will indicate if the virus is:– CCR5-tropic (R5)

– Dual/Mixed-tropic (DM)

– CXCR4-tropic (X4)

DHHS. Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents. Washington, DC: Office of AIDS Research Advisory Council, US Dept of Health and Human Services; December 1, 2007.Monogram Biosciences. FAQs-patient questions. Available at: http://www.trofileassay.com/FAQ_Patient_Questions.

34

Exercise: Sam Gets a Tropism Test

• Sam is on his 3rd regimen and has learned that his virus is multidrug resistant

• His health care provider has recommended a tropism test

• Sam is attending a treatment education workshop and asks the facilitator about tropism testing

• How would you explain the tropism test to Sam?

• Under what circumstances might Sam require a tropism test?

• What would you tell Sam is the most important information he needs to know about the tropism test?

• What questions should Sam ask his health care provider about the tropism test?


35

• The entry inhibitor test assesses resistance to Fuzeon® (enfuvirtide)

• Entry inhibitor tests may be used:

– Before changing a regimen that includes Fuzeon

– Before adding Fuzeon if a health care provider suspects resistance

Entry Inhibitor Assay

Fuzeon is a registered trademark of Roche Laboratories Inc. and Trimeris, Inc.

Monogram Biosciences. PhenoSense Entry advanced technology for assessing HIV. Available at: http://www.monogramhiv.com/assays/hcp/phenoEntryAssay.aspx.

Monogram Biosciences. PhenoSense Entry technology. Available at: http://www.monogramhiv.com/assays/hcp/phenoEntryAssay.aspx.

36

Integrase Inhibitor Assay

• The integrase inhibitor test assesses resistance to integrase inhibitors

• This test can help health care providers determine:– Whether HIV is resistant to integrase inhibitors and NRTIs

– How active HIV is in the presence of integrase inhibitors

Hoffmann CJ, Gallant JE. Infect Dis. 2007;33:1-33. Monogram Biosciences. PhenoSense™ and GeneSeq™ for integrase inhibitors assays. Available at: http://www.monogrambio.com/416.aspx.

NRTIs = nucleoside reverse transcriptase inhibitors.

37

Summary

• Looking at a person’s lab results—including CD4+ T-cell count, VL, and resistance—can help in making the best decisions for that individual

• Just as new drugs are continually being developed to improve care, new lab tests are continually being investigated

• Such tests may help to further individualize treatment and improve health outcomes

• Tropism testing is now available which allow health care providers to determine the co-receptor tropism of a patient’s virus

• The DHHS guidelines recommend tropism testing prior to the initiation of a CCR5 antagonist


38

Tests for Tracking

Overall Health3

39

Tracking Overall Health

• Tracking a patient’s overall health will help a health care provider:

– Monitor toxicities or other problems caused by HIV and the drugs used to treat it

– Track other health conditions that may arise because of aging or other factors

• Most tests are done at baseline (when first diagnosed with HIV or starting care) and then usually every 3 to 6 months, depending on individual risk factors and health care provider recommendations

40

What Is It? Why Is It Important?

Blood test to measure a number of important chemicals produced by the body to help it function properly

• Monitors:

– Liver, kidney, heart, and pancreas function

– Drug toxicities and side effects

• Helps determine whether another infection is present

• May influence treatment decisions

Chemical Screen

Tests performed at baseline and usually every 3 to 6 months thereafter, depending on individual factors as determined by the health care provider.

Hoffmann CJ, Gallant JE. Infect Dis. 2007;33:1-33.HIVInSite. Understanding laboratory tests. Available at: http://hivinsite.ucsf.edu/InSite?page=pb-diag-02-00.

41

What Is It? Why Is It Important?

• Blood test that examines the components of blood, including red and white blood cells and platelets

• Some drugs can cause low red or white blood cell counts, which can lead to anemia or other blood disorders

Complete Blood Count

Tests performed at baseline and usually every 3 to 6 months thereafter, depending on individual factors as determined by the health care provider.


42

•Test What Is the Purpose? Why Is it Important?

Hepatitis A, B, C • Screen for hepatitis infections

Tuberculosis (TB) and Toxoplasmosis

• Screen for opportunistic infections, TB, and toxoplasmosis

Sexually Transmitted Diseases (STDs)

• Screen for syphilis, chlamydia, gonorrhea, and other STDs

Tests for Other Related Health Conditions

• If left untreated, hepatitis B and C can lead to severe scarring of the liver, liver failure, and liver cancer

• These infections can become serious if untreated, and may be transmitted to sexual partners

• These infections can become very serious if undiagnosed and untreated

Hoffmann CJ, Gallant JE. Infect Dis. 2007;33:1-33.DHHS. Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents. Washington, DC: Office of AIDS Research Advisory Council, US Dept of Health and Human Services; December 1, 2007.CDC. Viral Hepatitis B. Available at: http://www.cdc.gov/ncidod/diseases/hepatitis/b/fact.htm.

43

Special Lab Tests/Exams for Women and Men

Women Men

What are other special tests for women?

What are other special tests for men?

44

Special Lab Tests/Exams for Women and Men

• Pap test (cervical and anal)

• Pelvic exam

• Colposcopy

• Breast exam

• Mammogram

• Hormone levels

• Anal screening

• Prostate cancer screening

• Hormone levels

Women Men

45

Tips For Lab Tests

• Before taking a test, be sure to follow the health care provider’s instructions:

– Are there any food restrictions?

– Are there any drugs that a person should avoid taking?

• To help ensure the accuracy of the test results, it’s important to:

– Tell the person collecting the sample if these instructions have not been followed, and how

– Inform the health care provider of any personal, medical, and family history and about any medications you are taking

• Other tips?

46

• Advances in medications and lab tests have revolutionized the detection, monitoring, and management of HIV

• Lab tests are essential for getting the most out of HIV treatments

• With new drugs and diagnostic tests that work in different ways, we look forward to improved approaches to managing HIV

Conclusion

47Pfizer accepts no responsibility for the content of these Web sites.

• Find more information about HIV lab tests on these Web sites:– ACRIA.org (AIDS Community Research Initiative of America)

– AIDSmeds.com

– AIDSInfoNet.org

– HIVandHepatitis.com

– ProjectInform.org (Project Inform)

– TheBody.com

– TPAN.com (Test Positive Aware Network)

Learn More

understanding hiv diagnostics and lab tests

Documents