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Table 1 Conventional Testing Regime: Private General Practice Clinic Setting – (Funded by Federal Government – Medicare)

From: Economic evaluation of alternative testing regimes and settings to detect undiagnosed HIV in Australia

  Probability of True HIV Positive
(PHIV)
Probability of True HIV Negative
(1 − PHIV)
Outcomes HIV Positive
(EIA+ & WB+)
False HIV Negative
(EIA-)
False HIV Positive
(EIA+ & WB-)
True HIV Negative
(EIA-)
Probability of result (PHIVSenEIASenWB) PHIV (1 − SenEIA) ((1 − PHIV)  (1 − SpecEIA) SpecWB) (1 − PHIV) SpecEIA
Inputs
Visit 1: Initial Screening
  Consult time 20 min 20 min 20 min 20 min
  Medicate Rebate $71.701 $71.701 $71.701 $71.701
  Staffing GP GP GP GP
Pathology costs
  EIA $15.652 $15.652 $15.652 $15.652
  WB confirmatory $29.003   $29.003  
Visit 2: Test Results
  Consult time 40 min 20 min 20 min 20 min
  Medicate Rebate $105.554 $71.701 $71.701 $71.701
  Staffing GP GP GP GP
Total Cost of Each Outcome $221.90 $159.05 $188.05 $159.05
Average cost (AC) per person tested =(PHIVSenEIASenWB) AC per True HIV PositiveEIA + , WB+ + (PHIV (1 − SenEIA)) AC per False HIV NegativeEIA + ((1 − PHIV) SpecEIA) AC per True HIV NegativeEIA + ((1 − PHIV)  (1 − SpecEIA) SpecWB)) AC per False HIV PositiveEIA + , WB
Average number of tests for a positive diagnosis \( =\frac{1}{P_{HIV}\ast Se{n}_{EIA}\ast Se{n}_{WB}} \)
  1. Note: AC Average Cost, EIA fourth generation enzyme immunoassay test, GP General Practitioner, P Probability, Sen Sensitivity, Spec Specificity, WB Western Blot Test, + reactive test result, − nonreactive test result
  2. 1 = Medicare Rebate Item 36; 2 = Medicare Rebate Item 69,384; 3 = Medicare Rebate Item 69,387; 4 = Medicare Rebate Item 44