An assessment of the utilization of diagnostic parasitology laboratory services in Ontario

Diagnostic parasitology services in Ontario were assessed to determine whether the reduction in the number of provider laboratories from 209 to 70 over the period 1977 to 1994 has affected the availability and quality of service.

A questionnaire on parasitology practice was distributed to all laboratories. Responses were validated against data from the requisitions, work cards and reports submitted by licensed parasitology laboratories in a pattern-of-practice survey.

Laboratories in Ontario are licensed by the provincial Ministry of Health and subjected to mandatory proficiency testing. Laboratories not licensed in parasitology may receive specimens for referral to another facility for processing.

Assessment included receipt of fecal specimens for parasitology, on-site testing, the limitation of testing, work referred elsewhere for primary investigation or confirmation, laboratory to which work was referred, and the turnaround time for both on-site and referred work.

Ninety-eight per cent of 338 laboratories returned the questionnaire. Three hundred and six received specimens for parasitology. Sixty-four performed the testing. Of the remainder, 235 referred to 40 laboratories. Approximately 31,000 specimens were processed monthly, with 78% examined within private laboratories and 62% having a turnaround time of at least three days. The yield of positive findings was 3% or more of patients.

The presence of fecal parasites has been reliably determined and the genus, species and stage of the organism correctly identified. Utilization must be improved through understanding of the factors increasing the pretest likelihood of a positive finding.