Trichrome staining for detection of intestinal protozoa a better screening method

Intestinal protozoal infections are common in our country because of poor hygiene and tropical conditions. The efficacy of trichrome staining to screen stool smear was compared with commonly used methods i.e. concentrated iodine mount and direct wet mount to test its better effectiveness. All Stool samples were first examined by routine methods i.e. direct wet mount and iodine staining. A portion of stool sample was also inoculated in vial containing polyvinyl alcohol (PVA) fixative. From PVA preserved samples, slides were prepared and stained by modified wheately's trichrome method. The results of both methods were compared and relative accuracy was calculated. 1054 stool specimens were examined and 259 parasites detected, of which 20.7% were protozoa and 3.7% helminthde. Trichrome staining detected 19.1% protozoa while routine methods detected 12.9% protozoa. For identification of protozoa, accuracy was 91.8% in favor trichrome staining and 61.8% by wet mount and iodine staining. Trichrome stained smear alone can be used as screening method in those geographic areas where protozoa infections are common.