ABSTRACT
OBJECTIVE: To evaluate the cost and effectiveness of parasite investigations in our laboratory in order to restrict the number of specimens. METHODS: The analysis were performed retrospectively on 53,701 specimens submitted for cysts, ova, and larvae, 224 specimens for intestinal trophozoites, 1,888 cellophane tape impressions, 3,134 malaria smears, and 524 bronchial aspirates. RESULTS: Potentially pathogenic parasites were demonstrated in 3.2% of specimens examined for cysts, ova, and larvae, 6% examined for intestinal trophozoites, 16% for pinworm, 7% for malaria, and 9% for Pneumocystis. The cost of demonstrating a single infection with a pathogenic parasite was calculated to be DKK 6206 for cyst, ova, and larva specimens. This cost could be reduced considerably, if the examination of patients with acute diarrhoea, but without a history of travel was omitted. Similarly, the demonstration of trophozoites, pinworm, malaria and Pneumocystis in a person was calculated to be DKK 1122, DKK 526, DKK 2874 and DKK 3716, respectively. Examination of three specimens for cysts, ova, and larvae showed 62-74% of the infections in the first sample. Two specimens increased the frequency of positive findings by 13-23% and three specimens by a further 9-12%. For the blood smears, 92% of the infections were demonstrated in the first sample. DISCUSSION: The analysis shows that to obtain an acceptable ratio between cost and diagnostic yield, the indication for the investigations should be tightened up. However, examination of three samples from each patient is necessary to exclude a parasitic infection.
