title: Use of pooling and outpatient laboratory specimens in an anonymous seroprevalence survey of HIV infection in British Columbia, Canada.
abstract: OBJECTIVE
  To conduct an anonymous HIV seroprevalence survey to establish a baseline estimate of HIV seroprevalence in a general population; to evaluate serum pooling and alternative testing strategies as cost-saving measures.
  
  
  METHODS
  Prospective anonymous HIV seroprevalence study using outpatient laboratory specimens.
  
  
  METHODS
  Two large non-hospital-associated outpatient chemistry testing laboratories in the major population centers in British Columbia, Canada. PATIENTS AND SERA: Leftover sera received for chemistry screen testing in outpatient laboratories were provided to the study after chemistry testing was completed. Those from patients aged < 15 and > or = 55 years were excluded.
  
  
  METHODS
  Patient identifiers were erased from samples. Sera were pooled 10:1 and tested by viral lysate enzyme-linked immunosorbent assay (ELISA). Sera from HIV-positive pools were tested individually. All individual HIV-positive specimens were retested for verification of positivity using a recombinant protein ELISA.
  
  
  METHODS
  HIV seroprevalence rates were stratified by sex, age group, and geographic area; and costs of pooling and alternative algorithm strategy were compared with those of conventional methods.
  
  
  RESULTS
  A total of 80,238 sera were collected from 66,658 individuals (53% women, 47% men). Of these, 276 men (88.3 per 10,000) and 24 women (6.8 per 10,000) were HIV-seropositive. The highest rates were in those aged 30-34 years, for both men and women. Using pooling and non-Western blot verification saved US$2.07 per specimen, or 80% of the cost for conventional testing.
  
  
  CONCLUSIONS
  The anonymous outpatient laboratory setting is practicable to obtain a reasonable estimate of HIV seroprevalence rates in a general population. Such studies can be made cost-effective by pooling sera and using alternative confirmatory strategies.
authors.affiliation: Department of Pathology, University of British Columbia, Vancouver, Canada.
authors.forename: C H
authors.initials: CH
authors.lastname: Sherlock
authors.forename: S A
authors.initials: SA
authors.lastname: Strathdee
authors.forename: T
authors.initials: T
authors.lastname: Le
authors.forename: D
authors.initials: D
authors.lastname: Sutherland
authors.forename: M V
authors.initials: MV
authors.lastname: O'Shaughnessy
authors.forename: M T
authors.initials: MT
authors.lastname: Schechter
mesh_terms: D015492:AIDS Serodiagnosis / Q000191:economics; D000293:Adolescent; D000328:Adult; D001955:British Columbia / Q000453:epidemiology; D003365:Costs and Cost Analysis; D005260:Female; D015528:HIV Seroprevalence; D006801:Humans; D007753:Laboratories; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D011446:Prospective Studies