How Quest Diagnostics can help

HIV Think Big continuum chart

Quest Diagnostics is committed to providing up-to-date test options to assist you in identifying HIV-infected patients. We have worked closely with the CDC1–4 to now offer the latest Fourth Generation HIV test that aligns with the HIV Fourth Generation Screening algorithm recommended by the CDC5 and Association of Public Health Laboratories (APHL).5 This new algorithm, published in 2014, improves upon the third generation HIV algorithm and replaces the original CDC HIV diagnostic algorithm, first published in 1989.

Reflex Pathway for the HIV-1/2 Antigen and Antibodies, Fourth Generation, with Reflexes Assay

The “HIV-1/2 Antigen and Antibodies, Fourth Generation, with Reflexes” assay has several important advantages over the “antibody-only-based” Third Generation HIV screening assay:

  • Detection of HIV p24 antigen in addition to HIV antibodies.
  • Confirmation of HIV-1 and HIV-2 antibodies using a single rapid test.
  • Confirmation of acute HIV-1 infection using an HIV-1 RNA assay.

Older doctor using tablet computerFor more information, see the Fourth Generation HIV test summary.

This latest HIV screening algorithm can shorten the window between virus acquisition and virus detection, helping to prevent transmission when the virus is at its most contagious and enabling earlier appropriate counseling and medical treatment for the patient.

Download our letter to physicians concerning the new Fourth Generation screening algorithm here, or read about our HIV experts.

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1. Delaney KP, Heffelfinger JD, Wesolowski LG, et al. Performance of an alternative laboratory-based algorithm for HIV diagnosis in a high-risk population. J Clin Virol. 2011;52(Suppl 1):S5–10. Available at:

2. Nasrullah M, Wesolowski LG, Meyer WA 3rd, et al. Performance of a fourth-generation HIV screening assay and an alternative HIV diagnostic testing algorithm. AIDS. 2013;27(5):731–7. Available at:

3. Wesolowski LG, Delaney KP, Hart C, et al. Performance of an alternative laboratory-based algorithm for diagnosis of HIV infection utilizing a third generation immunoassay, a rapid HIV-1/HIV-2 differentiation test and a DNA or RNA-based nucleic acid amplification test in persons with established HIV-1 infection and blood donors. J Clin Virol. 2011;52(Suppl 1):S45–9. Available at:

4. Wesolowski LG, Delaney KP, Meyer WA 3rd, et al. Use of rapid HIV assays as supplemental tests in specimens with repeatedly reactive screening immunoassay results not confirmed by HIV-1 Western blot. J Clin Virol. 2013;58(1):240–4. Available at:

5. Centers for Disease Control and Prevention and Association of Public Health Laboratories. Laboratory testing for the diagnosis of HIV infection: updated recommendations. June 27, 2014. Available at:

6. Centers for Disease Control and Prevention (CDC). Interpretation and use of the Western blot assay for serodiagnosis of human immunodeficiency virus type 1 infections. MMWR Morb Mortal Wkly Rep. 1989;38(Suppl 7):1–7.