A field evaluation of the formol-detergent method for concentrating faecal parasites.

A faecal parasite concentration method which utilizes a formalin-detergent solution has recently been described. This technique was evaluated under field conditions in the Out-Patient Department of a hospital in Northern Tanzania. Fifty faecal samples were examined by saline wet preparation and following formol-detergent concentration. Forty-one different parasite identifications were made by both techniques. Ten parasites were found only on saline wet preparation, and 20 were found only in the formol-detergent concentrate. The method necessitates a 24-h delay in sending a report, which is not justified by the small improvement in diagnostic yield. The authors believe that a modification of the technique may yet achieve acceptable results.