Document 2675
 DOCN  M94A2675
 TI    Cost effectiveness of different confirmatory HIV testing schedules in
       Colombia.
 DT    9412
 AU    Boshell J; Gonzalez M; Rey E; Rojas MC; Marrugo S; Instituto Nacional de
       Salud, Bogota, Colombia.
 SO    Int Conf AIDS. 1994 Aug 7-12;10(1):250 (abstract no. PB0429). Unique
       Identifier : AIDSLINE ICA10/94369900
 AB    OBJECTIVE: To compare the cost-effectiveness of two different testing
       strategies for HIV infection using data from a follow-up study. METHODS:
       The NIH of Colombia (Instituto Nacional Salud-INS) in Bogota is the
       HIV-Nat. Reference Lab. and performs WB testing on all sera with an
       Initial Reactive Screening Assay (IRSA) submitted by Blood Banks and
       public and Private labs in the country. A total of 6648 WB tests were
       performed between 1990-93 and 1644 had in Indeterminate (IND) report
       following the allgorithm IRSA-WB-REPORT. We traced 134 IND individual
       for whom additional sera were available after the first INS report.
       RESULTS: Forty seven of 134 samples (35%) became negative in the WB
       after a time interval of (3-143) weeks, 22 became positive (16%) after
       (2-130) weeks and 65 continued to give an IND WB serology after (3-165)
       weeks of follow-up. We were able to assay an average of 2,3 (2-4)
       2,1(2-3) and 2,4 (2-6) samples in each category. A second ELISA (Abbott)
       was performed at the INS on the 65 samples in the IND category after
       follow-up: 51 were negative (79%) an 14 (21%) continued positive.
       Reactivity for HILV-I antibodies was tested by ELISA and WB, in 32 (49%)
       of these 65 IND sera: none were WB positive. PCR has not yet been
       performed on any sample. DISCUSSION AND CONCLUSIONS: Many international
       agencies (WHO, PAHO, CDC) recommend that only duplicate repeat reactive
       initial screening results be confirmed by a supplemental test. Our
       experience confirms this recommendation, as we found that 79% of the
       samples giving an IND WB result were not repeatedly reactive by ELISA.
       If this result holds true for the 1644 IND WBs performed in our 3 year
       study period, it would suggest that 1299 of these assays were
       unnecesary. If we take in to account a cost of US$60 per assay we could
       have saved 60 x 1299 x 2.4 = US$187.056.00 by performing a repeated
       ELISA before carrying out the WB.
 DE    AIDS Serodiagnosis/*ECONOMICS  Blotting, Western/ECONOMICS  Colombia
       Comparative Study  Cost-Benefit Analysis  *Developing Countries
       Enzyme-Linked Immunosorbent Assay/ECONOMICS  Follow-Up Studies  Human
       HIV Antigens/*BLOOD  HIV Seropositivity/*DIAGNOSIS/ECONOMICS/IMMUNOLOGY
       Predictive Value of Tests  MEETING ABSTRACT

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