Evaluation of a commercially available ELISA for detection of Giardia lamblia antigen in faeces: preliminary results in unconventional samples.

The sensitivity and specificity of a commercial ELISA for the diagnosis of G. lamblia were assessed on a series of 52 formalin-ether concentrated, unrefrigerated faecal samples after prolonged storage. Before storage the CELISA did not perfectly accord with microscopy. All the 30 microscopically positive samples scored highly positive on ELISA after storage, including 2 samples that had given a false negative result when examined soon after collection. There was no false positive ELISA. The sensitivity of the test therefore seems to be enhanced by storage at room temperature without any corresponding fall in specificity.