+ Understanding HIV-Related Lab Tests Jordan E. Lake, MD, MSc AAHU Sept 1, 2015

+ Labs 101 “Why do you need to take so much blood!?!”

+ Labs 101: Three Questions What labs do we draw? What do these labs tell us? How often do we need these labs?

+ T cells 101 T cell: a type of immune system cell T cells become infected by HIV when the virus recognizes proteins on the T cell surface One of these proteins is called CD4 Doctors and patients may talk about T cells or CD4 cells (same thing)

+ T cells 101: Number The number of T cells tells us how healthy the immune system is As the immune system becomes weaker from HIV, the number of T cells goes down (they die and your body can’t make more) t

+ T cells 101: Number A normal immune system has how many T cells? t

+ T cells 101: Number A normal immune system has how many T cells? ≥500 cells/mm 3 t

+ T cells 101: Number A normal immune system has how many T cells? ≥500 cells/mm 3 A weak immune system has how many T cells? t

+ T cells 101: Number A normal immune system has how many T cells? ≥500 cells/mm 3 A weak immune system has how many T cells? cells/mm 3 t

+ T cells 101: Number A normal immune system has how many T cells? ≥500 cells/mm 3 A weak immune system has how many T cells? cells/mm 3 AIDS=how many T cells? t

+ T cells 101: Number A normal immune system has how many T cells? ≥500 cells/mm 3 A weak immune system has how many T cells? cells/mm 3 AIDS=how many T cells? <200 cells/mm 3 t

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+ T cells 101: Function When T cells are not infected with HIV, they help to fight infection and cancer As T cell number decreases and T cells become weaker, their ability to “help” goes down

+ HIV Viral Load 101 Viral load (VL) is the amount of HIV in the blood in copies/mL Without HIV medicines, VL is high With effective HIV medicines, no new HIV viruses are made, and the VL goes down

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+ HIV Viral Load 101 Q: What does “undetectable” mean?

+ HIV Viral Load 101 Q: What does “undetectable” mean? A: Undetectable means there is less HIV in the blood than the test can detect, NOT -That the virus is gone from the body (t he virus can lives in many places in the body other than blood) - That cells in the body are no longer infected with HIV (blood cells can be infected with HIV but not release virus into the blood)

+ Where is the HIV Virus in the Body?

+ How Do HIV Medications Affect T cells and the HIV Viral Load?

+ Effective HIV Medicines Stop new HIV virus from being made Stop T cells from dying Allow the body the chance to make new T cells

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+ HIV Resistance Testing 101 Genotype: -tells us what medications the HIV virus is sensitive to -It is specific to each person, and helps doctors choose medication regimens Phenotype: -tells us how likely the person is to be resistant to a given HIV medication

+ HIV Genotype 101

+ Archived Resistance Testing “Standard” genotype tells us what the major mutations are at the time of blood draw Archived genotype tells us what mutations have been there in the past too

+ When To Check Labs T cell count: at diagnosis, then every 3-6 months HIV Viral Load: at diagnosis, 4 weeks after starting HIV medicines, 12 weeks after starting medicines, then 2-3 times per year Genotype: at diagnosis, if VL going up on medicines and resistance suspected

+ Other Labs We Check Kidneys: blood creatinine, urinalysis Liver: AST, ALT, bilirubin Anemia: hemoglobin Immune system: white and red blood cell counts and characteristics Cholesterol: lipid panel STIs: RPR, Gonorrhea/Chlamydia as appropriate for individual patient Viral hepatitis: Hepatitis A,B, and C at diagnosis, Hepatitis B and C if liver abnormalities, plus Hepatitis C antibody yearly for MSM

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