Study guide
4.7 HIV Diagnosis, Antiretroviral Therapy & Prevention
ABIM Internal Medicine Exam
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1 Chapter 0: The ABIM Exam, Blueprint & Study Strategy
0.1 Exam Format, Question Types & the 2026 Blueprint 0.2 Eligibility, Registration, Fees & Exam-Day Logistics 0.3 Scoring, the Passing Standard & Score Reports 0.4 Building a Blueprint-Weighted Study Plan
2 Chapter 1: Cardiovascular Disease (14% of Exam)
1.1 Ischemic Heart Disease & Acute Coronary Syndromes 1.2 Antithrombotic Therapy, Secondary Prevention & Mechanical Complications of MI 1.3 Atrial Fibrillation, Atrial Flutter & Stroke Prevention 1.4 Supraventricular Tachycardias, Ventricular Arrhythmias & Bradycardias 1.5 Heart Failure: Classification, Staging & Guideline-Directed Medical Therapy 1.6 Device Therapy, HFpEF & the Cardiomyopathies 1.7 Valvular Heart Disease & Endocarditis Prophylaxis 1.8 Pericardial Disease & Acute Aortic Syndromes 1.9 Hypertension: Classification, Diagnosis & Secondary Causes 1.10 Hypertensive Crises & Dyslipidemia 1.11 Adult Congenital Heart Disease & Coarctation of the Aorta 1.12 Syncope: Reflex, Orthostatic & Cardiac Causes 1.13 Cardiac Physical Examination, Murmurs & Antithrombotic Selection
3 Chapter 2: Endocrinology, Diabetes & Metabolism (9% of Exam)
2.1 Diabetes Mellitus: Diagnosis, Glycemic Targets & Pharmacotherapy 2.2 Insulin Therapy, Hyperglycemic Emergencies & Chronic Complications 2.3 Thyroid Function Testing & Hypothyroidism 2.4 Thyrotoxicosis, Thyroid Storm & Thyroid Nodules 2.5 Adrenal & Pituitary Disorders 2.6 Hypercalcemia, Hypocalcemia & Disorders of Mineral Metabolism 2.7 Osteoporosis & Paget Disease of Bone 2.8 Ovarian, Testicular & Reproductive Endocrine Disorders 2.9 Hypoglycemia, Endocrine Tumors, Polyglandular Syndromes & Severe Hypertriglyceridemia
4 Chapter 3: Gastroenterology & Hepatology (9% of Exam)
3.1 Esophageal Disease 3.2 Stomach & Duodenal Disease and Gastrointestinal Hemorrhage 3.3 Inflammatory Bowel Disease 3.4 Celiac Disease & Irritable Bowel Syndrome 3.5 Diverticular Disease & Colorectal Cancer Screening 3.6 Viral Hepatitis, Steatotic & Alcohol-Associated Liver Disease 3.7 Cirrhosis & the Complications of Portal Hypertension 3.8 Acute Pancreatitis 3.9 Chronic Pancreatitis & Biliary Tract Disease 3.10 Inherited, Autoimmune & Drug-Induced Liver Disease 3.11 Small Intestinal Disease, Ischemia & Gastrointestinal Complications of HIV
5 Chapter 4: Infectious Disease (9% of Exam)
4.1 Lower Respiratory Tract Infections & Sepsis Syndromes 4.2 Viral Respiratory Pathogens & Tuberculosis 4.3 Central Nervous System Infections 4.4 Skin, Soft Tissue, Bone & Joint Infections 4.5 Infective Endocarditis & Cardiovascular Infection 4.6 Clostridioides difficile & Catheter-Related Bloodstream Infection 4.7 HIV Diagnosis, Antiretroviral Therapy & Prevention 4.8 Opportunistic Infections & Sexually Transmitted Infections 4.9 Fever of Unknown Origin, Neutropenic Fever & Toxic Shock 4.10 Travel-Related Illness, Vector-Borne Disease & Outbreaks 4.11 Infection Prevention, Nosocomial Infection & Postexposure Prophylaxis 4.12 Rheumatic Fever, Poststreptococcal Disease, Enteric & Hepatic Infections
6 Chapter 5: Pulmonary Disease (9% of Exam)
5.1 COPD: Diagnosis, GOLD Classification & Initial Pharmacotherapy 5.2 Interventions That Reduce COPD Mortality & Exacerbation Management 5.3 Asthma: Diagnosis, Stepwise Therapy & Status Asthmaticus 5.4 Interstitial Lung Disease & Idiopathic Pulmonary Fibrosis 5.5 Sarcoidosis, Hypersensitivity Pneumonitis & Occupational Lung Disease 5.6 Pulmonary Embolism: Diagnosis, Risk Stratification & Anticoagulation 5.7 Pulmonary Hypertension & Sleep-Disordered Breathing 5.8 Acute Respiratory Distress Syndrome & Mechanical Ventilation 5.9 Pleural Disease, Empyema & Pneumothorax 5.10 Bronchiectasis, Cystic Fibrosis & Restrictive Lung Disease 5.11 Evaluation of Cough, Dyspnea, Hemoptysis & the Solitary Pulmonary Nodule
7 Chapter 6: Rheumatology & Orthopedics (9% of Exam)
6.1 Rheumatoid Arthritis: Diagnosis & Systemic Manifestations 6.2 Antirheumatic Pharmacotherapy & the Spondyloarthropathies 6.3 Gout: Pathophysiology & Acute Management 6.4 Urate-Lowering Therapy & Calcium Pyrophosphate Deposition Disease 6.5 Osteoarthritis 6.6 Systemic Lupus Erythematosus 6.7 Systemic Sclerosis, Sjogren Syndrome & Inflammatory Myopathies 6.8 The Vasculitides 6.9 Regional Musculoskeletal Syndromes, Back Pain & Sports Injuries 6.10 Other Primary Rheumatic Disorders & Mixed Connective Tissue Disease 6.11 Osteonecrosis & Metabolic Bone Disease
8 Chapter 7: Hematology (6% of Exam)
7.1 Approach to Anemia & the Microcytic Anemias 7.2 Macrocytic, Normocytic & Hemolytic Anemias 7.3 Hemoglobinopathies, Thalassemias & Paroxysmal Nocturnal Hemoglobinuria 7.4 Platelet Disorders, Thrombocytopenia & the Bleeding Patient 7.5 Coagulation Factor Disorders, Thrombophilia & Anticoagulant Reversal 7.6 Acute Leukemias, Chronic Leukemias & Myeloproliferative Neoplasms 7.7 Lymphomas & Plasma Cell Disorders 7.8 Myelodysplastic Syndrome, Myeloproliferative Neoplasms & Porphyria 7.9 Transfusion Medicine & Late Complications of Transplantation
9 Chapter 8: Medical Oncology (6% of Exam)
8.1 Breast, Lung, Colorectal & Prostate Cancer 8.2 Oncologic Emergencies 8.3 Genitourinary & Gynecologic Malignancies 8.4 Head and Neck, Bone & Soft Tissue Cancer and Cancer of Unknown Primary 8.5 Complications of Cancer & Its Treatment 8.6 Cancer Prevention, Survivorship & Psychosocial Care
10 Chapter 9: Nephrology & Urology (6% of Exam)
9.1 Acute Kidney Injury: Staging, Etiology & Urine Microscopy 9.2 Glomerular Disorders & Nephrotic Syndrome 9.3 Nephritic Syndromes, RPGN & Indications for Renal Replacement Therapy 9.4 Chronic Kidney Disease: Staging & Progression Retardation 9.5 Complications of Chronic Kidney Disease: Anemia, CKD-MBD & Acidosis 9.6 Hyponatremia, Hypernatremia & Water Balance 9.7 Potassium Disorders & Systematic Acid-Base Analysis 9.8 Renal Tubular Acidosis & Nephrolithiasis 9.9 Prostate Disorders, Urinary Incontinence & Other Urologic Conditions 9.10 Cystic Kidney Disease, Obstructive Uropathy, Tubulointerstitial Disease & Hematuria
11 Chapter 10: Neurology (4% of Exam)
10.1 Acute Ischemic Stroke: Syndromes & Reperfusion 10.2 Transient Ischemic Attack, Secondary Prevention & Hemorrhagic Stroke 10.3 Headache & Facial Pain 10.4 Seizures, Epilepsy & Movement Disorders 10.5 Multiple Sclerosis & Neuromuscular Junction Disorders 10.6 Motor Neuron Disease & Acute Peripheral Neuropathy 10.7 Cranial Neuropathies & Neuro-Ophthalmology 10.8 Peripheral Neuropathies, CNS Tumors & Other Neurologic Disorders
12 Chapter 11: Psychiatry & Behavioral Health (4% of Exam)
11.1 Major Depressive Disorder & Medical Mimics 11.2 Antidepressant Pharmacotherapy & Treatment-Resistant Depression 11.3 Bipolar Disorder, Mood Stabilizers & Lithium Toxicity 11.4 Anxiety, Stress-Related & Obsessive-Compulsive Disorders 11.5 Alcohol Use Disorder & Withdrawal 11.6 Pharmacotherapy for Alcohol & Opioid Use Disorder 11.7 Toxidromes, Psychiatric Emergencies & Suicide Risk Assessment 11.8 Psychotic, Somatic Symptom, Factitious & Personality Disorders 11.9 Eating Disorders, Sleep Disorders & Sexual Health
13 Chapter 12: Dermatology (3% of Exam)
12.1 Dermatitis, Papulosquamous & Inflammatory Dermatoses 12.2 Acne, Rosacea & Cutaneous Infections 12.3 Herpes Zoster & Autoimmune Blistering Diseases 12.4 Nodules, Tumors & Cutaneous Oncology 12.5 Dermatologic Emergencies & Severe Cutaneous Adverse Reactions 12.6 Pigment Disorders, Alopecia, Nail Disease & Photosensitivity 12.7 Vascular Dermatoses, Environmental Injury & Cutaneous Signs of Systemic Disease
14 Chapter 13: Obstetrics & Gynecology / Women's Health (3% of Exam)
13.1 Contraception, Preconception Care & Teratogenicity 13.2 Hypertensive Disorders of Pregnancy & Gestational Diabetes 13.3 Thyroid Disease & Venous Thromboembolism in Pregnancy 13.4 Menopause & Menopausal Hormone Therapy 13.5 Abnormal Uterine Bleeding, Endometrial Disease & Gynecologic Cancer Screening 13.6 Breast Disorders & Diseases of the Vulva and Vagina 13.7 Menstrual Disorders, Fibroids, Endometriosis & Early Pregnancy Complications
15 Chapter 14: Geriatric Syndromes (3% of Exam)
14.1 Comprehensive Geriatric Assessment & Frailty 14.2 Falls, Gait Assessment & Polypharmacy 14.3 Urinary Incontinence & Pressure Injuries in Older Adults 14.4 Mild Cognitive Impairment, Dementia & Its Subtypes 14.5 Delirium & the Pharmacotherapy of Cognitive Disorders 14.6 Palliative Care, Hospice & Advance Care Planning 14.7 Chronic Wounds, Nutrition, Swallowing, Constipation & Hip Fracture 14.8 Sensory Impairment, Dizziness, Elder Mistreatment & Care Settings
16 Chapter 15: Allergy & Immunology (2% of Exam)
15.1 Anaphylaxis: Recognition & Emergency Management 15.2 Urticaria & Angioedema 15.3 Drug Allergy, Desensitization & Adult Immunodeficiency 15.4 Food Allergy, Insect Venom Hypersensitivity, Serum Sickness & Contrast Reactions 15.5 Rhinitis, Conjunctivitis, Eosinophilic & Mast Cell Disorders
17 Chapter 16: Preventive Medicine, Immunization & Clinical Epidemiology
16.1 The USPSTF Framework & Evidence-Based Cancer Screening 16.2 Cardiovascular & Metabolic Screening and Primary Prevention 16.3 Adult Immunization & Vaccines in Special Populations 16.4 Clinical Epidemiology, Biostatistics & Study Design
18 Chapter 17: Miscellaneous - Ethics, Patient Safety & Quality Improvement (2% of Exam)
17.1 Principles of Bioethics & Decisional Capacity 17.2 Informed Consent, Treatment Refusal & Special Scenarios 17.3 Surrogate Decision-Making, Advance Directives & Confidentiality 17.4 Patient Safety Science, Medical Error & Diagnostic Reasoning 17.5 Quality Improvement Methods, Health Disparities & Health Equity
19 Chapter 18: Perioperative Medicine & Medical Consultation
18.1 Preoperative Cardiovascular Risk Assessment 18.2 Preoperative Pulmonary Risk & Perioperative Medication Management 18.3 Perioperative Anticoagulation, Bridging & Postoperative Complications
20 Chapter 19: Ophthalmology (1% of Exam)
19.1 The Acute Red Eye & Ophthalmic Emergencies 19.2 Painless Vision Loss & Chronic Ophthalmic Disease 19.3 Uveitis, Scleritis & Orbital Disease
21 Chapter 20: Otolaryngology & Dental Medicine (1% of Exam)
20.1 Dizziness, Vertigo & Epistaxis 20.2 Ear Disorders, Hearing Loss & Upper Respiratory Infections 20.3 Oral Cavity, Salivary Gland, Laryngeal & Taste and Smell Disorders
4.7 HIV Diagnosis, Antiretroviral Therapy & Prevention
Key Takeaways Explain This Topic AI
Transmission and prevention of HIV and prevention of opportunistic infections are explicitly enumerated within the HIV blueprint subsection.
Fourth-generation antigen-antibody immunoassay is the recommended initial test, with a supplemental differentiation assay and, when discordant, HIV RNA testing.
Acute retroviral syndrome may occur before antibodies develop, so HIV RNA testing is required when acute infection is suspected.
HLA-B*5701 testing is mandatory before abacavir because a positive result predicts a potentially fatal hypersensitivity reaction.
Sustained virologic suppression prevents sexual transmission, and pre-exposure prophylaxis requires confirmed HIV-negative status and periodic retesting.
Last updated: August 2026
Management of Human Immunodeficiency Virus (HIV), sexually transmitted infections (STIs), and opportunistic infections (OIs) is among the most frequently tested areas on the ABIM examination. This section provides detailed guidance on diagnostic algorithms, antiretroviral therapy (ART) selection, pre/post-exposure prophylaxis, CD4-stratified opportunistic infections, and syphilis staging.
- 1. HIV Diagnosis & Initial Evaluation
- CDC Diagnostic Testing Algorithm
Step 1: 4th-Generation HIV-1/2 Antigen/Antibody Combination Immunoassay: Detects both HIV-1 and HIV-2 antibodies and the HIV-1 p24 antigen (detectable within 14–20 days after infection, significantly narrowing the diagnostic window compared to antibody-only assays).
If non-reactive -> Negative for HIV infection.
If reactive -> Proceed to Step 2.
Step 2: HIV-1 / HIV-2 Antibody Differentiation Immunoassay:
If positive for HIV-1 or HIV-2 antibodies -> Confirmed HIV-1 or HIV-2 infection.
If negative or indeterminate (antibodies not yet formed in acute early infection) -> Proceed to Step 3.
Step 3: HIV-1 RNA Qualitative / Quantitative Nucleic Acid Test (NAT / Viral Load):
If HIV-1 RNA is detectable -> Confirms Acute HIV-1 Infection .
If HIV-1 RNA is undetectable -> False-positive initial screen.
Comprehensive Baseline Laboratory Evaluation
CD4+ T-Lymphocyte Count and Percentage: Assesses degree of immune deficiency and guides opportunistic infection prophylaxis.
Plasma HIV-1 RNA Viral Load: Establishes baseline virologic burden to monitor response to ART.
HIV Genotypic Resistance Testing: Evaluates reverse transcriptase (RT) and protease (PR) genes; obtain integrase strand transfer inhibitor (INSTI) genotype if INSTI-based therapy planned.
HLA-B*5701 Allele Screening: Mandatory prior to initiating Abacavir (ABC) . Patients positive for HLA-B*5701 are at high risk for a fatal, multisystem Abacavir Hypersensitivity Reaction (fever, rash, GI symptoms, dyspnea). If positive, Abacavir is permanently contraindicated and must be recorded as an allergy.
Hepatitis Serologies: Hepatitis B (HBsAg, anti-HBs, anti-HBc) and Hepatitis C (HCV Ab with reflex RNA). Tenofovir (TDF or TAF) + Emtricitabine or Lamivudine treat both HIV and HBV.
G6PD Level: Baseline screening required before prescribing oxidant medications (Dapsone, Primaquine) for opportunistic infection prophylaxis/treatment.
STI & Latent TB Screening: Syphilis serology (RPR/VDRL), urine/mucosal NAAT for N. gonorrhoeae and C. trachomatis , and IGRA or TST for latent tuberculosis.
Loading diagram... HIV Opportunistic Infection Prophylaxis & Management Roadmap by CD4 Threshold
- 2. Antiretroviral Therapy (ART) & Prevention Strategies
- Core Principles of ART
Universal Indication: ART is recommended for all individuals with HIV infection , regardless of CD4 cell count, to decrease morbidity/mortality and prevent transmission ( Undetectable = Untransmittable [U=U] ).
Rapid Initiation: ART should be initiated immediately (or same day as diagnosis) whenever possible.
Preferred Initial ART Regimens (2 NRTIs + 1 INSTI Backbone)
Bictegravir / Tenofovir Alafenamide / Emtricitabine (Biktarvy - BIC/TAF/FTC): Single-tablet regimen once daily. High barrier to resistance, excellent tolerability, no HLA-B*5701 testing required.
Dolutegravir / Tenofovir Alafenamide (or TDF) / Emtricitabine (or Lamivudine): (DTG + TAF/FTC or DTG + TDF/FTC).
Dolutegravir / Abacavir / Lamivudine (Triumeq - DTG/ABC/3TC): Single-tablet regimen; requires confirmed negative HLA-B*5701 and negative HBV status (Abacavir does not have activity against HBV).
Two-Drug Initial Regimen — Dolutegravir / Lamivudine (Dovato - DTG/3TC): Approved for initial therapy ONLY IF baseline HIV-1 RNA viral load is <500,000 copies/mL , patient has no Hepatitis B co-infection , and resistance testing shows no NRTI or INSTI mutations.
NRTI Comparison: TDF versus TAF
Tenofovir Disoproxil Fumarate (TDF): Higher circulating plasma levels; associated with tubular nephrotoxicity (Fanconi syndrome, proteinuria, acute tubular injury) and loss of bone mineral density (osteopenia/osteoporosis).
Tenofovir Alafenamide (TAF): Targeted intracellular uptake in lymphoid tissue with 90% lower plasma levels; significantly reduces renal and bone toxicities (preferred in patients with underlying renal dysfunction or osteoporosis).
Pre-Exposure Prophylaxis (PrEP) & Post-Exposure Prophylaxis (PEP)
PrEP Regimens:
Daily Oral Emtricitabine / Tenofovir Disoproxil Fumarate (FTC/TDF - Truvada): Approved for all populations at risk (men who have sex with men [MSM], heterosexual men and women, injection drug users).
Daily Oral Emtricitabine / Tenofovir Alafenamide (FTC/TAF - Descovy): Approved for MSM and transgender women; NOT approved for individuals at risk from receptive vaginal sex (due to lack of clinical efficacy trial data in cisgender women).
Injectable Cabotegravir (Apretude): Extended-release IM injection administered every 2 months (following two monthly initial doses). Superior efficacy over daily oral PrEP in clinical trials.
Mandatory PrEP Rules: Document a negative HIV-1 Ag/Ab test and viral load within 1 week prior to initiating or renewing PrEP to prevent emerging resistance if infected. Check eGFR (>=60 for TDF; >=30 for TAF) and STI screen every 6 months.
PEP (Post-Exposure Prophylaxis):
Initiated following occupational (needlestick) or non-occupational (unprotected sexual assault or intercourse) exposure.
Timing: Must be initiated within <=72 hours of exposure.
Duration & Regimen: 28-day course of 3-drug therapy : Tenofovir (TDF or TAF) + Emtricitabine (FTC) PLUS Dolutegravir (50 mg daily) OR Raltegravir (400 mg BID) .