HIV infection

Last reviewed: 22 Aug 2023
Last updated: 29 Jun 2023



History and exam

Key diagnostic factors

  • fevers and night sweats
  • weight loss
  • skin rashes and post-inflammatory scars
  • oral ulcers, angular cheilitis, oral thrush, or oral hairy leukoplakia
  • diarrhea
  • wasting syndrome
  • changes in mental status or neuropsychiatric function
  • recent hospital admissions
  • tuberculosis (TB)
  • medical comorbidities
  • sexual activity
  • generalized lymphadenopathy
  • Kaposi sarcoma
  • genital STIs
  • chronic vaginal candidiasis
  • shingles
  • headaches
  • periodontal disease
  • retinal lesions on fundoscopy
  • shortness of breath on exertion, cyanosis on exertion, dry cough, silent chest on auscultation
More key diagnostic factors

Other diagnostic factors

  • current and prior use of other substances
  • peripheral neuropathy
  • recurrent herpes simplex
  • hepatomegaly or splenomegaly
  • meningeal signs (bacterial or viral meningitis)
Other diagnostic factors

Risk factors

  • people who inject drugs
  • gay men and other men who have sex with men
  • commercial sex worker
  • transgender women
  • unprotected receptive anal intercourse
  • unprotected receptive penile-vaginal sexual intercourse
  • percutaneous needle stick injury
  • racial and ethnic minorities
  • high maternal viral load (mother-to-child transmission)
  • use of progestin-only injectable contraceptives
  • herpes simplex virus type 2 (HSV-2) infection
More risk factors

Diagnostic investigations

1st investigations to order

  • serum HIV enzyme-linked immunosorbent assay (ELISA)
  • serum HIV rapid test
  • HIV noninvasive tests
  • serum Western blot
  • serum p24 antigen
  • serum HIV DNA polymerase chain reaction (PCR)
  • CD4 count
  • serum viral load (HIV RNA)
  • drug resistance testing
  • pregnancy test
  • serum hepatitis B serology
  • serum hepatitis C serology
  • CBC with differential
  • basic metabolic panel
  • urinalysis
  • liver function tests (LFTs)
  • random or fasting plasma glucose
  • lipid profile
  • human leukocyte antigen-B*5701 testing
More 1st investigations to order

Investigations to consider

  • chest x-ray
  • hepatitis A serology (IgG)
  • toxoplasma serology (IgG)
  • testing for sexually transmitted infections
  • tuberculin skin test
More investigations to consider

Treatment algorithm


newly confirmed infection


virologic or immunologic treatment failure



Chad J. Achenbach, MD, MPH

Associate Professor of Medicine

Infectious Diseases

Northwestern Medicine

Feinberg School of Medicine, Northwestern University




CJA has been paid for service on a Data Safety Monitoring Board by ABIVAX.


Dr Chad J. Achenbach would like to gratefully acknowledge Dr Richard Rothman, Dr Michael Ehmann, Dr Linda-Gail Bekker, Dr Catherine Orrell, and Dr Lisa Capaldini, the previous contributors to this topic.


ME, LGB, and CO declare that they have no competing interests. RR attended a symposium/conference hosted by a funding agency, Gilead HIV FOCUS program, from which he receives research funds. RR pays staff for an implementation/research program grant from Gilead HIV FOCUS for development of HIV testing programs in Emergency Departments. LC is on the speakers' bureau for the following pharmaceutical companies: GlaxoSmithKline, BMS, Merck, Gilead, Roche, Pfizer, Solvay, Lilly, Serrano, and Tibotec.

Peer reviewers

Marianne Harris, MD

Clinical Assistant Professor

University of British Columbia




MH is a member of an advisory board and/or speakers' bureau for Gilead Sciences Canada Inc, Merck Canada Inc, and ViiV Healthcare.

William Rodriguez, MD

Assistant Professor of Medicine

Harvard Medical School

Director of Research

Global Health Delivery Project

Harvard School of Public Health




WR declares that he has no competing interests.

Jeremy Day, BChir, MB

Infectious Disease Physician

Oxford University Clinical Research Unit

Hospital for Tropical Diseases

Ho Chi Minh City



JD declares that he has no competing interests.

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