Table 1.

Summary of Variables

VariableBaseline EstimateRange Used in Sensitivity AnalysisSource
EIA = enzyme immunosorbent assay; HIV = human immunodeficiency virus; PHI = primary HIV infection; CBC = complete blood count; G6PD = glucose-6-phosphate dehydrogenase; CMV = cytomegalovirus; RPR = rapid plasma reagin; PPD = purified protein derivative (tuberculin); NAAT = nucleic acid amplification test.
* Initial battery of laboratory tests includes: CBC, chemistry panel, G6PD assay, toxoplasmosis titer, CMV titer, RPR, PPD skin test, viral hepatitis panel, lipid panel, urinalysis, chest radiograph, urine NAAT for gonorrhea and chlamydia.
Costs ($)
    p24 antigen EIA24.6512.33–49.30Medicare fee schedule
    HIV-1 RNA assay118.8959.45–237.78Medicare fee schedule
    Third-generation HIV-1 EIA19.179.59–38.34Medicare fee schedule
    Western blot assay27.0513.53–54.10Medicare fee schedule
    CD4 cell count per microliter9045–180Medicare fee schedule
    Initial battery of laboratorys tests (new diagnosis)*254200–614Medicare fee schedule
    Expanded testing program costs101.4751–203MMWR20
    Discounted lifetime medical costs (diagnosed with PHI and antiretroviral therapy started at CD4 cell count of 350/μL)95,80047,900–191,600Freedberg et al23
    Discounted lifetime medical costs (PHI not diagnosed and antiretroviral therapy started when HIV diagnosed)88,10044,050–176,200Freedberg et al23
    Return visit52.5340–67.86Kaplan & Anderson24
Test characteristics
    p24 antigen EIA, sensitivity0.8870.770–0.957Hecht et al,8 Daar et al9
    Specificity0.99960.9950–0.9999Hecht et al,8 Daar et al9
    HIV-1 RNA, sensitivity1.000Hecht et al,8 Daar et al9
    Specificity0.9800.950–0.999Hecht et al,8 Daar et al9
    Third-generation HIV-1 EIA, sensitivity0.7900.600–0.920Hecht et al8
    Specificity0.9700.930–0.990Hecht et al8
    Probability of indeterminate Western blot0.000004Kleinman et al22
Prevalence factors (%)
    Patients lost to follow-up3116–62MMWR21
    Prevalence in screened population0.660.53–0.92Coco & Kleinhans16
    Sexual transmission factors
    Patients who change behavior to avoid infecting sexual partner500–96MMWR6
    Patients that are sexually active5025–85MMWR6
    Infectivity (probability of sexual transmission during PHI period)150–30Yerly et al,25 Pilcher et al26
    Asymptomatic HIV infection0.9370.926–0.949Schackman et al27
    Anxiety while waiting for confirmatory test results for patients with a positive screen0.6820.400–0.800Kaplan & Anderson24
Quality-adjusted life-expectancy (discounted), years
    No PHI24NCHS15
    Positive screening result, no PHI23.973523.950–23.983NCHS,15 Kaplan & Anderson24
    PHI diagnosed at screening with follow-up care and antiretroviral treatment started at CD4 cell count of 350/μL11.911.832–11.952Freedberg et al23
    PHI not diagnosed at screening or lost to care with antiretroviral treatment started when HIV diagnosed11Freedberg et al23