Human Immunodeficiency Virus Book

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HIV Test

Aka: HIV Test, HIV Antibody, HIV Screening, HIV Labs
  1. Indications
    1. See HIV Screening Indications
  2. Labs: HIV Diagnosis (2014 U.S. protocol)
    1. Step 1: HIV-1/HIV-2 EIA Antibody Test with p24 Antigen testing (fourth generation)
      1. Negative
        1. No HIV-1 or HIV-2 Antibody or p24 Antigen
        2. p24 Antigen is detectable by HIV Testing as early as 2 weeks after infection
        3. High Negative Predictive Value
        4. Retest in 2-4 weeks if new HIV Exposure in prior 2 weeks
      2. Positive
        1. Go to Step 2 for discriminatory assay
    2. Step 2: HIV-1/HIV2 Discriminatory Assay (Multispot)
      1. Negative for HIV-1 and HIV-2
        1. Go to step 3 for confirmatory, NAAT testing
        2. If NAAT Test not available, then report as HIV Indeterminate
      2. HIV-1 Antibody positive (most common in U.S.)
        1. Obtain viral load
        2. Start Combination Antiretroviral Therapy
      3. HIV-2 Antibody positive (West Africa, nRTI resistance)
        1. Start Combination Antiretroviral Therapy
    3. Step 3: HIV-1 RNA Nucleic Acid Amplification Test (NAT or NAAT) for HIV RNA Viral Activity
      1. Negative NAAT
        1. Retest in 2-4 if new HIV Exposure in prior 2 week
      2. Positive NAAT
        1. Acute HIV Infection (although rare False Positive tests occur)
        2. Start Combination Antiretroviral Therapy
  3. Labs: Timing of HIV Test detection (from transmission)
    1. Days 10-12 (1-2 weeks)
      1. HIV 1 nucleic acid amplification test (NAAT) for HIV RNA Viral Activity positive
    2. Days 15-17 (2 weeks)
      1. HIV p24 Antigen positive
    3. Day 21 (3 weeks)
      1. HIV-1/HIV-2 EIA Test (fourth generation) positive
    4. Day 28 (4 weeks)
      1. HIV-1/HIV2 Discriminatory Assay (Multispot)
    5. Day >35 (5 weeks)
      1. Unigold OraQuick positive
      2. HIV Western Blot positive
    6. References
      1. Masciotra (2011) J Clin Virol 52(Suppl 1):S17-22 [PubMed]
  4. Labs: HIV Screening
    1. First line screening (recommended)
      1. Combined HIV-1/HIV-2 Antibody and p24 Antigen Immunoassay (fourth generation test)
    2. Other HIV rapid Screening Tests (office based, perform Multispot/NAAT testing if positive)
      1. Uni-Gold Recombigen
      2. Alere Determine
        1. Rapid finger-stick test detects p24 Antigen and detects and distinguishes HIV-1 and HIV-2 Antibody
        2. Approved in U.S. by FDA in 2013
      3. OraQuick (oral swab based)
        1. Available as In-Home HIV Test as of 2013
        2. Approved for age 17 years old and older
        3. Results in 20-40 minutes
        4. Test Sensitivity
          1. Approaches 99% when performed in clinic
          2. Drops to 92% (False Negative Rate: 1 in 12) when performed at home (due to user error)
        5. Test Specificity: 99.98% (False Positive Rate: 1 in 5000)
        6. Most accurate at 3 months after exposure
    3. Older tests (replaced)
      1. HIV ELISAAntibody Test (1st generation HIV Tests)
        1. Replaced with other Screening Tests above
        2. Positive 3-8 weeks from infection
        3. Were often negative initially in acute onset
  5. Labs: Other HIV Tests (confirmatory, discriminatory and activity tests)
    1. CD4 Cell Count
      1. Best marker of HIV-related Immunosuppression, infection duration and prognosis
      2. Varies from person to person, lab to lab, by time of day, and most significantly by acute comorbid illness
    2. HIV-1/HIV2 Discriminatory Assay (Multispot)
      1. Discriminates between HIV-1 and HIV-2
    3. HIV-1 RNA Nucleic Acid Amplification Test (NAT or NAAT) for HIV RNA Viral Activity (HIV Viral Load)
      1. Test Sensitivity: 100% sensitive
      2. Test Specificity: 97.4% Specific
      3. Positive at 11-12 days from infection
      4. Higher rate of False Positives
      5. Low counts (<10,000) are often False Positives
    4. Labs: p24 Antigen (direct detection)
      1. Positive at 14-15 days from infection (falls within 6-8 weeks)
      2. Used as part of screening protocol (see above)
      3. Consider for Acute Retroviral Syndrome diagnosis
      4. Test Sensitivity: 88.7% (high False Negative Rate)
      5. Test Specificity: 100%
      6. (2001) Ann Intern Med 134:25-29 [PubMed]
    5. Older tests
      1. HIV Western Blot Assay
        1. Use as confirmatory test for first generation HIV Tests
        2. Replaced with Multispot and NAAT testing following 4th generation combination HIV-1/HIV-2/p24 tests
  6. Efficacy: False-negative HIV Test causes (Consider repeat testing or HIV Viral Load testing)
    1. Acute seroconversion (<4 weeks of HIV Infection)
    2. Advanced AIDS (Antibody based tests)
    3. Autoimmune Condition
    4. Hemodialysis patients (Renal Failure)
    5. Multiple pregnancies
    6. Multiple transfusions
    7. Cystic Fibrosis
    8. Liver disease
    9. Intravenous Drug Abuse
    10. Immunization
      1. HIV Vaccination (experimental only)
      2. Recent other Immunization
  7. Labs: Related Sexually Transmitted Disease Testing
    1. Syphilis Serology (Rapid Plasma Reagin, VDRL)
    2. Hepatitis B Serology
    3. Hepatitis C Serology
    4. Gonorrhea Culture
    5. Chlamydia Antigen
  8. Labs: Disease Screening Related to Advanced HIV or AIDS
    1. Tuberculin Skin Test (PPD, Mantoux)
      1. Consider Quantiferon-TB instead
      2. Dose: 0.5 cc injected (contrast with standard 0.1 cc)
      3. Positive: >5 mm (contrast with standard 10 mm)
    2. CytomegalovirusSerology (CMV)
    3. Toxoplasmosis Titer
    4. Gynecologic examination with Pap Smear
      1. HIV associated with advanced Cervical Cancer
  9. References
    1. (1997) Med Lett Drugs Ther 39:81-3 [PubMed]
    2. Mylonakis (2000) Arch Intern Med 160:2386-8 [PubMed]
    3. Sherin (2014) Am Fam Physician 89(4): 265-72 [PubMed]

HIV screen (C0459958)

Concepts Laboratory Procedure (T059)
SnomedCT 171121004, 148344008, 393926007, 392970006, 395052001
English HIV screen, Human immunodeficiency virus (HIV) screening, AIDS HIV tests, HIV screening tests, HIV testing, HIV tests, AIDS hiv testing, AIDS testing, AIDS tests, HIV test, AIDS test, screening HIV, Human immunodeficiency virus (HIV) screening (procedure), Human immunodeficiency virus screening (procedure), Human immunodeficiency virus screening, HIV screening (procedure), HIV screening test (procedure), AIDS (HTLV-III) screening, HIV screening, HIV screening test
Spanish cribado de VIH, detección selectiva de VIH, detección selectiva de virus de inmunodeficiencia humana, detección selectiva de VIH (procedimiento), cribado para la detección del HIV, cribado para la detección del virus de la inmunodeficiencia humana, detección selectiva de virus de inmunodeficiencia humana (procedimiento), cribado para la detección del virus de la inmunodeficiencia humana (procedimiento), cribado para la detección del VIH, detección selectiva de HIV, pesquisa de HIV, pesquisa de VIH, screening de HIV, screening de VIH, tamizaje de HIV, tamizaje de VIH
Sources
Derived from the NIH UMLS (Unified Medical Language System)


Human immunodeficiency virus test (C1321876)

Definition (CSP) any clinical test whose results can be used to diagnosis AIDS; including tests for HIV infection, CD4 lymphocyte count, tests for microorganisms such as Pneumocystis, etc.; for diagnosis by symptoms and other factors, use AIDS DIAGNOSIS.
Concepts Laboratory Procedure (T059)
SnomedCT 143221005, 165813002
English AIDS test, AIDS antibody test, Acqu immunodefic syndr ab test, HIV - Hum immunodef virus test, Human immunodefic virus test, HIV test, HIV tests, HIV Measurement, Test;HIV, AIDS/HIV test, AIDS - Acquired immunodeficiency syndrome antibody test, Acquired immunodeficiency syndrome antibody test, HIV - Human immunodeficiency virus test, Human immunodeficiency virus test (procedure), Human immunodeficiency virus test, AIDS Testing, HIV Testing, Test;AIDS(HIV)
Italian Test del virus dell'immunodeficienza umana
Dutch HIV-tests, HIV-test
French Tests VIH, Sérologie VIH
German HIV-Tests, HIV-Test
Portuguese Testes de HIV, Teste de HIV
Spanish Pruebas del VIH, prueba de detección del virus de HIV, prueba de detección del virus de VIH, prueba de detección del virus de inmunodeficiencia humana (procedimiento), prueba de detección del virus de inmunodeficiencia humana, Prueba VIH
Japanese ＨＩＶ検査, HIVｹﾝｻ
Czech Vyšetření na HIV
Hungarian HIV vizsgálatok, HIV vizsgálat
Sources
Derived from the NIH UMLS (Unified Medical Language System)


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