Whole Blood Elisa Using Coconut Water-tween as a Wash Solution

PBS-Tween as a wash solution, prepared with distilled water, is used in ELISA. In areas where schistosomiasis is endemic, however, distilled water is hard to come by. We have modified a WHOLE BLOOD-ELISA test to use coconut water-Tween as a wash solution, because coconut water is easy to come by and cheap in the tropics. We applied the test to whole blood samples from rabbits and humans infected with Schistosoma japonicum. This modified WHOLE BLOOD-ELISA was confirmed to be a rapid, simple, and cost-effective method. SOUTHEAST ASIAN J TROP MED PUBLIC HEALTH 1384 Vol 36 No. 6 November 2005 in August 2002, and treated with 0.001% heparin. Samples were either used immediately or treated with 5% sodium azide (1 drop reagent/ 1 ml sample) and stored in a refrigerator. S. japonicum eggs were confirmed by Kato-Katz thick smear technique (Katz et al, 1972) and formalin-detergent technique (Moody, 1986). The first stool examination was performed by KatoKatz thick smear technique. After one month, feces were again collected from the residents who were stool negative from S. japonicum eggs and were examined successively for 1 to 5 days by both Kato-Katz thick smear and formalin-detergent techniques. Some of the people were also infected with Ascaris lumbricoides, hookworm, or Trichuris trichiura. Positive human serum samples were separated by centrifugation at 1,710g for 5 minutes at room temperature and then stored at -80oC until use. Negative human serum samples were donated by the students of Dokkyo University School of Medicine, Japan, with no history of schistosomiasis and treated and stored as described above.